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Pediatric Emergency Medicine POCUS

Created in 2020 by series editor, Dr. Margaret Lin-Martore, this series focuses on point-of-care ultrasonography (POCUS) for pediatric emergency medicine (PEM).

 

PEM POCUS Series: Pediatric Cardiac

PEM POCUS pediatric cardiac

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric cardiac evaluation. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. List the indications and limitations of pediatric cardiac point-of-care ultrasound (POCUS)
  2. Describe the technique for performing cardiac POCUS
  3. Identify anatomical landmarks accurately on cardiac POCUS
  4. Interpret abnormal findings on cardiac POCUS
  5. Describe the basic literature behind pediatric cardiac POCUS

Case Introduction: Child with respiratory distress

You are in the emergency department evaluating a 2-month-old full-term male infant presenting with worsening respiratory distress over the past few days. He has had no fever, rhinorrhea, congestion, or cough. He is feeding poorly and has only had two wet diapers in the past 24 hours.
On arrival, his vital signs are:

Vital SignFinding
Temperature36.4 C
Heart rate190 bpm
Blood pressure97/63
Respiratory pate62
Oxygen saturation (room air)95%

Exam

He is ill-appearing. The cardiac exam is notable for tachycardia and 2+ femoral pulses. There is no appreciable murmur. Pulmonary exam shows tachypnea, clear lungs, and mildly increased work of breathing. The abdomen is mildly distended with a liver palpable 2 cm below the costal margin. Capillary refill is 2 seconds.

Diagnostics and Management

You order a chest x-ray and labs, and order blood and urine cultures. You start a fluid bolus and empiric antibiotics. While waiting for your initial work-up, you perform a cardiac POCUS.

Cardiac POCUS can help providers rapidly identify significant cardiac pathology and drastically change management. The major POCUS questions are qualitative evaluation of:

  1. Ventricular function
  2. Pericardial effusion
  3. Relative chamber sizes
  4. Fluid tolerance (or volume status)

In the context of cardiac arrest, POCUS can assess the presence of cardiac activity. Additionally, performing repeat cardiac POCUS exams can help providers gauge response to interventions.

Limitations

Cardiac POCUS is NOT a replacement for comprehensive echocardiography. A number of applications are beyond the scope of cardiac POCUS and should be evaluated by comprehensive echocardiography, including:

  • Valvular pathology
  • Structural abnormalities
  • Congenital heart defects
  • Quantitative measurements (i.e., quantitative ventricular function, flow measurements)

Like other POCUS applications, sonographer skill and experience can influence the sensitivity/specificity of the exam to detect abnormalities.

 

  • Supine positioning as tolerated. Raise head of bed if needed for comfort.
    • Left lateral decubitus position can improve the A4CH and parasternal views.

Figure 1. Phased array ultrasound probe

  • Phased array probe: Smaller footprint for intercostal windows and useful for moving objects.
  • Cardiac setting on the machine (if available). Can improve temporal resolution of the images.
  • Tips for young children:
    • If fearful of staff, consider seating the child in the guardian’s lap.
    • Distract the child with a video or toy.
    • Obtain the subxiphoid view last (as this sometimes requires pressure).
    • Warmed gel can be very helpful!

A cardiac POCUS includes five standard views of the heart and inferior vena cava (below). Sonographers should recognize each of the ideal views and limitations of suboptimal views.

  • Parasternal long axis (PSLA or PLAX)
  • Parasternal short axis (PSSA or PSAX)
  • Apical four chamber view (A4CH)
  • Subxiphoid view (SUBX)
  • Inferior vena cava (IVC)

A note on probe marker orientation:

Probe marker orientation varies across pediatric disciplines, including cardiology, pediatric emergency medicine, critical care, and neonatology. This especially differs for the parasternal long axis view (discussed in more detail below). This may result in an image that appears “flipped,” or rotated 180 degrees, on the screen. Practice obtaining the views in your local environment, but also gain comfort interpreting a flipped image.

(Although all views can be used to evaluate gross ventricular function and for pericardial effusion, highlights of each view are listed below.)

Highlights of View

  • Excellent overall assessment
  • Gross LV function
  • Pericardial effusion
  • General chamber sizes

Probe Placement

Figure 2 PSLA probe placement

Figure 2. PSLA probe placement with phased array probe. (Image from Dr. Margaret Lin-Martore)

  1. Place the probe to the left of the sternum, near the 3rd-4th intercostal space.
  2. Point the probe marker towards the patient’s left hip.
  3. Slide the probe up and down intercostal spaces to obtain an ideal window.
  4. Make subtle adjustments to optimize the view.

In this image and the ones below, note that the probe is larger than a typical phased-array probe (Figure 1).

Note: The direction of the probe marker, especially for the parasternal long axis, may vary across specialties and institutions. Some specialties point the probe marker towards the left hip and others towards the right shoulder. This may result in an image that appears “flipped” (or rotated 180 degrees) on the screen.

Normal View and Landmarks

normal pediatric cardiac POCUS PSLA view

Video 1: Normal PSLA cardiac view (Image from thepocusatlas.com. Images: Dr. Lindsay Davis, Dr. Hanna Kopinski. Image Editing: Michael Amador and Dr. Matthew Riscinti)

Color labels in video:

  • Right ventricle (green)
  • Left ventricle (violet)
  • Left atrium (teal)
  • Mitral valve (yellow-brown), visualize both leaflets with the anterior leaflet centered and hitting or nearly hitting the septum
  • Aortic valve (pink)
  • Descending aorta (black circle behind pericardium)
  • Pericardium (pink), note tapering anterior to the descending aorta

Troubleshooting and Tips

  • If the left ventricle is oblique (and not horizontal across the screen), slide up a rib space.
  • The patient can hold breath in exhalation to decrease lung artifact.
  • Ensure adequate depth to see the descending aorta.
  • Try subtle micro-adjustments (fan and rotate the probe until you obtain the ideal image).
  • If the lung is obscuring the view, try rolling the patient into the left lateral decubitus position.

Normal Ultrasound Video (PSLA)

Video 2. Normal PSLA view

Highlights of View

  • Gross LV function
  • Interventricular septum position

Probe Placement

PSSA probe placement

Figure 3. Probe placement for PSSA. From the PLSA view, center the left ventricle (LV) on the screen then rotate the probe 90° clockwise towards the right hip.

 

Normal View and Landmarks

video normal PSSA view

Video 3: Normal PSSA view (Image from thepocusatlas.com – Dr. Lindsay Davis, Dr. Hanna Kopinski. Image editing: Michael Amador and Dr. Matthew Riscinti.)

 

Color labels in video:

  • Left ventricle (red)
  • Mitral valve (blue)
  • Right ventricle (top of the screen)

The ideal view is at the mid-papillary level, meaning both papillary muscles are visible in the LV at approximately 4 and 8 o’clock.  Note that this video starts with the “fish mouth” view of the mitral valve and ends with the mid-papillary view.

Additional views: Fanning through the PSSA view, starting at the apex → mid-papillary view → “fish mouth” view of the mitral valve → “Mercedes-Benz” view of the aortic valve (video 3A).

 Video 3a. Troubleshooting the PSSA view with the “PSSA sweep”

 

Troubleshooting and Tips

  • If you see the “fish mouth” view of the mitral valve, fan the probe towards the apex to visualize the papillary muscles.
  • If you only see one papillary muscle, anchor that side of the probe and move the other side of the probe back-and-forth (like a windshield wiper) until you find the second papillary muscle.
Video 3b. Troubleshooting the PSSA View -The Windshield Wiper:
If you cannot find the view, try sliding the probe towards the apex. Alternatively, you can return to the PSLA view and rotate from there. Rock the probe to center the LV on the screen.

 

Video 3c. Troubleshooting the PSSA view: Rocking the probe

Normal Ultrasound Video (PSSA)

Video 4. Normal PSSA view

Highlights of View

  • Gross chamber sizes
  • Interventricular septum position

Additional Uses:

  • Global assessment of function
  • Another view for pericardial effusion
  • Can be useful in cardiac arrest during active compressions (though SUBX most commonly used)
  • Pro tip: often helpful for advanced applications (calculations and evaluation for valvular dysfunction)

Probe Placement

Probe placement for apical 4-chamber view (A4CH)

Figure 4. Probe placement for apical 4-chamber view (A4CH). Image from Dr. Margaret Lin-Martore.

  1. From the PSSA view, slide the probe towards the apex of the heart, keeping the probe marker towards the patient’s right hip.
  2. Flatten the probe to point it towards the right shoulder.
  3. For patients with breast tissue, place the probe near the inframammary line.

Normal View and Landmarks

Normal A4CH view

Video 5: Normal A4CH view (Image from thepocusatlas.com. Images: Dr. Lindsay Davis, Dr. Hanna Kopinski. Image Editing: Michael Amador and Dr. Matthew Riscinti.)

Color labels in video:

  • Left ventricle, left atrium, mitral valve (blue, screen right)
  • Right ventricle, right atrium, tricuspid valve (red, screen left)
  • A5CH view includes the aortic outflow tract (video 5 above initially shows the A5CH view before becoming the A4CH view)
Normal A4CH view with labels

Figure 5. Normal A4CH view with labels

Troubleshooting and Tips

Ventricle differentiation: Regardless of probe marker orientation, you can still differentiate the 2 ventricles in a number of ways:

  1. The tricuspid valve inserts more apically (towards the top of the screen) than the mitral valve.
  2. The LV connects to the aortic outflow tract.
  3. The LV occupies the most apical point of the heart.
  4. The RV contains the moderator band near the apex.
Figure 5 Probe placement A4CH left lateral decub

Figure 6. Left lateral decubitus positioning for A4CH probe positioning

Optimize views:

  1. Roll the patient onto their left side (left lateral decubitus) to bring the heart towards the chest wall and decrease lung artifact (figure 5). This maneuver improves PSLA and PSSA views too, but can be essential to acquire the A4CH view.
  2. If the heart appears oblique, you are likely too medial.
    1. Slide laterally.
    2. Flatten the probe.
    3. Point the probe towards the right shoulder.

Normal Ultrasound Video

Video 6. Normal apical 4-chamber (A4CH) views

Highlights of View

  • Pericardial effusion (most sensitive view)
  • Cardiac arrest (most commonly used)

Probe Placement

Figure 6 subxiphoid view probe

Figure 7. Subxiphoid view probe placement (Image from Dr. Margaret Lin-Martore)

  1. With the probe marker pointing to the patient’s right, place the probe inferior to the xiphoid process.
  2. Switch to an overhand grip, flatten the probe, apply adequate pressure, and point towards the patient’s left shoulder.

Normal View and Landmarks

Video 7 SUBX view normal

Video 7. Normal subxiphoid view (Image from thepocusatlas.com by Dr. Lindsay Davis, Dr. Hanna Kopinski. Image Editing: Michael Amador and Dr. Matthew Riscinti)

Anatomy in video:

  • Liver (top of the screen)
  • Left ventricle and atrium (red)
  • Right ventricle and atrium (blue) (RV = most anterior chamber)

Troubleshooting and Tips

  • Position the patient supine if possible.
  • Have the patient bend knees to relax abdominal muscles.
  • Have the patient hold breath in inhalation to move the heart inferiorly.
  • Slowly apply moderate pressure to displace bowel gas. Sometimes children cannot tolerate the pressure needed for an adequate view.
  • Using the liver as an acoustic window, try sliding the probe to the patient’s right and pointing the probe towards the patient’s heart through the liver.

Pro tip: Sweeping through this view can allow further assessment for pericardial effusions

Normal Ultrasound Video

 Video 8. Normal subxiphoid view

Highlights of View

  • Rough estimate of fluid tolerance / volume status
  • Adjunct to overall hemodynamic assessment

Probe Placement

Figure 7. Probe placement for IVC transverse view

Figure 8. Probe placement for IVC transverse view. Tilt the probe perpendicular to the patient in a similar location as the subxiphoid view with probe marker to patient’s right. (Image from Dr. Margaret Lin-Martore)

Figure 8. Probe placement IVC sagittal

Figure 9. Probe placement for IVC sagittal view. Center the IVC on the screen, then rotate the probe 90 degrees with probe marker to patient’s head. Slide the probe cephalic until you see the IVC entering the right atrium.  (Image from Dr. Margaret Lin-Martore)

Notes:

  • It is important to evaluate the IVC at its maximum diameter. If you are off-axis in this view, the IVC may appear artificially narrower.
  • Practice obtaining both views, as occasionally it can be difficult to obtain one of the two views depending on patient comfort and the presence of bowel gas.

Normal View and Landmarks

Figure 9. IVC transvere view with anatomy labels

Figure 10. IVC transverse view with anatomy labels. Locate the spinal column (shadowing posteriorly). This shadowing can be seen even in a patient with a larger body habitus. Just anterior to the spinal column, locate the IVC (screen left, patient right) and abdominal aorta (screen right, patient left).

Figure 10 IVC sagittal view labelled

Figure 11. IVC sagittal view with anatomy labels. Visualize the IVC entering into the right atrium (note the hepatic vein draining into the IVC). Examine for collapsibility just distal to the hepatic vein.

Measurements

Various IVC measurements exist, including IVC collapsibility index and IVC-aorta ratio.

1. IVC Collapsibility Index

In the sagittal plane at the level of the IVC just distal to the entry of the hepatic vein, measure the maximum and minimum IVC diameters. A collapsibility index of >50% may represent volume responsiveness.

  • IVC collapsibility index = [Max IVC diameter – Min IVC diameter] / Max IVC diameter

2. IVC-Aorta Ratio

In the transverse plane near the entry of the renal vein, measure the maximum IVC and aorta diameters. Numerous cutoffs for IVC/Ao ratio exist, and can vary by patient age. An IVC/Ao ratio < 0.8 may be suggestive of dehydration.

  • IVC/Ao ratios vary by age, ranging from 0.83 (young infants) to 1.22 (older children) [1].

Please see Facts and Literature Review section for more information on IVC and volume status.

Troubleshooting and Tips

Transverse

  • Many structures can be mistaken for the IVC, including the aorta, portal vessels, and gallbladder. Locate the IVC using the spinal column (shadowing deep on the screen). In a patient without situs inversus, the IVC will be located on screen left (patient right), and the aorta is located on the other side. Both vessels may appear pulsatile, and the IVC shape can change depending on a variety of hemodynamic factors.

Sagittal

  • A common mistake is misidentifying the aorta as the IVC. The aorta is located more to the patient’s left and dives more posteriorly as it crosses the diaphragm. “Prove” that the vessel is the IVC by showing:
    1. The IVC entering the right atrium
    2. The hepatic vein draining into the IVC
  • Because the IVC is a cylindrical structure, it can look like it is completely collapsing if you are located on the edge of the vessel.

Serial IVC Exams:

  • Repeating the IVC exam after interventions (like giving a fluid bolus) can be more helpful than evaluating the IVC at a single point in time.

Normal Ultrasound Video

Video 9: Inferior vena cava (transverse view)
Video 10. Inferior vena cava (sagittal view)

Cardiac POCUS is used primarily to detect significant abnormalities, including:

  1. Gross ventricular dysfunction
  2. Pericardial effusion +/- cardiac tamponade
  3. Gross chamber dilation
  4. Completely collapsed or plethoric IVC

Left Ventricular Systolic Dysfunction

  •     Goal is to identify clinically significant moderate/severe dysfunction.
  •     Qualitative assessment is sufficient, and pattern recognition is important!
  •     As with any diagnostic test, clinical correlation is key
  •     Views: Best assessed on PSLA and PSSA
  •     PSLA:
    • Qualitative assessment of overall “squeeze,” including wall thickening and decrease in chamber size
    • Anterior leaflet of mitral valve excursion: The anterior leaflet should touch or nearly touch the interventricular septum during diastole. Adult POCUS commonly measures this distance, known as EPSS (E-point septal separation); however, age-specific norms are not yet defined in children.
      • Pitfall – An oblique view can underestimate mitral valve movement.
  •     PSSA: 
    • Qualitative assessment of overall “squeeze.”
    • The LV chamber diameter should shorten by ~1/3 and have uniform concentric contraction.

Note: Lung POCUS views may show diffuse B-lines. These vertical white lines originating from the pleura can suggest pulmonary edema in the presence of heart failure. Please see ALiEM PEM POCUS Series: Pediatric Lung Ultrasound for more information.

Ultrasound videos of severe LV dysfunction

Video 11. PSLA view – Severe LV dysfunction in a teenager with new diagnosis of cardiomyopathy. Note the poor overall squeeze, poor excursion of the anterior leaflet of the mitral valve, and lack of thickening of the LV free wall.

 

Video 12. PSSA view in the same patient – note the poor concentric squeeze of the left ventricle

 

Video 13. PSLA view – Severe LV dysfunction in a young infant presenting with failure to thrive and ALCAPA (anomalous left coronary artery from the pulmonary artery). Again note the poor overall squeeze, poor excursion of the anterior leaflet of the mitral valve, lack of thickening of the LV free wall, and dilation of the LV.

 

Video 14. PSSA view – Again note the poor concentric squeeze of the LV and the LV dilation.

  • Views: An effusion should be visible on multiple views.
  • SUBX view:
    • Most sensitive view
    • Pericardial effusion is located between the liver and the right ventricle.
  • PSLA view:
    • Both pericardial and pleural effusions can be seen posterior to the heart.
    • Pericardial effusions track anterior to the descending aorta.
    • Pleural effusions stop posterolateral to the descending aorta and do not cross anteriorly.

Figure 12. Pericardial and pleural effusion on PSLA view

Beware of 2 potential false positives when evaluating for pericardial effusion.

1. Pericardial fat pad

In the PSLA view, this looks like a hypoechoic rim anterior to the heart (closest to probe marker) but NOT posterior to the heart. Typically a fat pad will move in sync with the heart while an effusion does not.

Video 15. Pericardial fat pad and effusion (From thepocusatlas.com by Dr. Dimitri Livshits; Dr. Jane Belyavskaya; Dr. Chris Hanuscin)

2. “Myocardial dropout”

Myocardial dropout occurs when ultrasound waves strike cardiac muscle fibers at specific angles, causing alterations in echogenicity. This acoustic phenomenon can result in the myocardium appearing as a hypoechoic rim. It’s important to note that this rim represents actual myocardial tissue rather than an external collection such as a pericardial effusion. By adjusting the probe angle during the examination, the echogenicity of the myocardium will correspondingly shift, confirming that the hypoechoic area is indeed myocardial tissue rather than a fluid collection (e.g., pericardial effusion).

Figure 13. “Myocardial dropout” effect with asterisks marking drop out area – Changes in echogenicity of the myocardium can sometimes look like a hypoechoic rim. This rim is within the myocardium and not external to the heart as expected for a pericardial effusion. (Image: Dr. Margaret Lin-Martore)

Ultrasound videos of pericardial effusion

Video 16. Pericardial effusion (PSLA view) – The anechoic pericardial effusion is anterior to the heart and also posterior to the heart, tapering just in front of the descending aorta.
Video 17. Pericardial effusion (PSSA view) – Note the circumferential pericardial effusion. A pathologic pericardial effusion should be visualized in multiple views.
Video 18. Pericardial effusion (A4CH view) – Note the pericardial effusion at the apex, right, and left sides of the heart.
Video 19. Pericardial effusion (SUBX view) – Note the pericardial effusion between the liver and the heart. This effusion also surrounds the apex of the heart. Remember that the subxiphoid view is the most sensitive view for detecting pericardial effusion.
Video 20. Trace pericardial effusion (PSLA view) – There is a trace pericardial effusion between the LV free wall and the pericardium. A trace effusion will disappear during part of the cardiac cycle.
Video 21. Pericardial and plerual effusions (PSLA view) – Note both the pericardial and pleural effusions. The pericardial effusion tapers anteriorly to the descending aorta. The pleural effusion stops laterally / posteriorly to the descending aorta.

Definitive diagnosis of cardiac tamponade is beyond the scope of this module, and immediate specialist consultation is recommended if there is clinical concern. However, some concerning ultrasound features would include:

Features:

  1. Circumferential pericardial effusion
  2. Right atrial systolic collapse (earliest sign)
  3. Right ventricular diastolic collapse (*most specific*)
  4. Plethoric IVC

Views:

  • Any view can be used, but the A4CH view shows right-sided structures best.
Video 22. Cardiac tamponade (A4CH view)

Right ventricular function assessment is beyond the scope of this module and typically cardiac POCUS is used as a general assessment. If there is clinical concern for this, specialist consultation is recommended.

Etiologies include pulmonary hypertension, pulmonary embolism, and right heart failure.

  • Increased RV size can suggest increased right heart pressures.
  • Views: Best assessed on A4CH and PSSA.
  • A4CH:
    • A dilated RV will be equal to or larger than the LV
    • Increased RV pressures cause flattening or bowing of the interventricular septum.
  • PSSA view:
    • Increased RV pressures cause flattening of the interventricular septum.
    • “D-sign” = The LV looks like the letter “D” from septal flattening

Figure 13. The D-sign (Image from thepocusatlas.com by Drs. Ronald Rivera, Elizabeth Hanson, Melanie Malloy, Kelly Maurelius, Kings County/SUNY Downstate Emergency Medicine.)

Pitfall:

Beware the “Pseudo D-Sign”. If only one papillary muscle is in view due to probe rotation, the interventricular septum may appear artificially flattened.

Figure 14. Pseudo D-Sign

Video 23. Pseudo D-Sign mimicking right ventricular dilation
Video 24. Right ventricular dilation (PSSA view) – Note the dilation of the right ventricle and flattening of the interventricular septum (D-sign).
Video 25. Right ventricular dilation (A4CH view) – Although this video is intermittently off axis, you can still appreciate right ventricular (RV) dilation. Note the enlarged right ventricle and bowing of the inter ventricular septum into the left ventricle. In a normal heart, the RV should be approximately 2/3 the size of the LV in the apical four chamber view. In infants, the RV can be equal to the size of the LV.
Video 26 RV dilation PSLA

Video 26. RV dilation (PSLA view) – Note the enlarged right ventricle at the top of the screen.

Video 27 McConnells sign PE

Video 27. McConnell’s sign in acute massive pulmonary embolism, showing akinesia of the lateral wall of the right ventricle and hypercontractility of the apical wall. (Image from thepocusatlas.com by Dr. Kelly Maurelus, Matthew Riscinti – Kings County Emergency Medicine)

In general, IVC assessment is most useful at the extremes:

  • Completely collapsed: Walls touch with inhalation.
    • Suggests the patient may benefit from fluid resuscitation.
    • Could be consistent with hypovolemia or distributive shock.
  • Completely plethoric (full): Minimal respiratory variation.
    • Suggests the patient may not need or tolerate significant fluid resuscitation.
    • May consider other medications or treatment.
    • Could be consistent with cardiogenic or obstructive shock.

When evaluating the IVC, it is important to interpret in the overall context of the patient’s presentation. For example, a plethoric IVC with minimal XXX

Video 28. Plethoric IVC – The IVC is very large and does not change in size with respiration.
Video 29. Flattened IVC – The IVC is flat and the walls completely collapse during inspiration.

Cardiac POCUS Literature

Much of the foundation for pediatric cardiac POCUS use is extrapolated from adult studies. Marbach et al. provide an excellent summary of the adult literature and highlights that cardiac POCUS improves clinicians’ bedside diagnostic accuracy, which influences management decisions, expedites time to diagnosis, and decreases resource use [2].

Pediatric-specific studies are summarized below. In general, cardiac POCUS demonstrates adequate sensitivity and specificity in evaluating for pericardial effusion and left ventricular systolic dysfunction [3]. POCUS may even be a promising adjunct to cardiology consultation for children with a variety of preexisting cardiac conditions [4]. These studies are primarily retrospective and warrant further future study.

In pediatric septic shock, cardiac POCUS can help clinicians characterize hemodynamics and often changes clinical management [5].

When it comes to interpretation errors, learners struggle more with evaluation for cardiac dysfunction and ventricle abnormalities than for pericardial effusion [6]. Additionally, novice trainees are more likely to make interpretation errors in real-time at the bedside than when reviewing images remotely [7]. These studies may inform future educational curricula surrounding pediatric cardiac POCUS.

YearAuthorsStudy Type, N, AgesFindings
2021Hamad et al. [9]Case series

  • 10 cases
  • Age 0-21 years
Examples of acute heart failure in children
2022Miller et al. [3]Retrospective review, single center (2015-2017)

  • 456 scans
  • Median age 14.7 years (IQR 9.1-17.5)
Test characteristics for cardiac POCUS interpretation by pediatric emergency medicine (PEM) physicians for detection of pericardial effusion (16 cases) and LV systolic dysfunction (18 cases)

PEM physicians compared to POCUS experts:

  • Pericardial effusion: Sn 100% / Sp 99.5%
  • LV dysfunction: Sn 100% / Sp 99.5%

PEM physicians compared to echocardiography done within 96 hours:

  • Pericardial effusion: Sn 88% / Sp 89%
  • LV systolic dysfunction: Sn 79% / Sp 96%
2024Hoffman et al. [4]Retrospective review,
single center (2015-2017)

  • 104 scans
  • Median age 16.3 years (IQR 8.6-20.1)
Test characteristics for cardiac POCUS interpretation by (PEM physicians for detection of pericardial effusion and LV systolic dysfunction in children with preexisting cardiac disease, including:

  • Congenital heart disease
  • Acquired cardiac disease
  • Arrhythmias

PEM physicians compared to POCUS experts:

  • Pericardial effusion: Sn 100% / Sp 98%
  • LV dysfunction: Sn 100% / Sp 99%

PEM physicians compared to echocardiography done within 96 hours:

  • Pericardial effusion: Sn 88% / Sp 87%
  • LV systolic dysfunction: Sn 100% / Sp 96%

Test characteristics were lower when including technically limited studies (5/104 studies).

Limitations:

  • Possible selection bias: POCUS may have been avoided in more complex cardiac patients
  • Exams with uninterpretable images were excluded (though were not common)
  • Only 1 patient with single ventricle included
2024Scott et al. [9]Retrospective review (pilot study)

  • 21 cases (9 POCUS)
  • Median age 11.8 years (IQR 4.9-16.8)
Examined time-based metrics if POCUS used in ED for pediatric heart failure.

  • Trend towards faster time to 1st IV heart failure medication (p<0.1).
  • No difference in ED or CICU length of stay.
Table 4. Key published studies on pediatric cardiac POCUS

IVC Literature

The evidence is highly variable for using IVC measurements (size, collapsibility index, IVC/Ao ratio) in isolation for predicting fluid responsiveness or central venous pressure [11-13]. A systematic review and meta analysis suggested IVC respiratory variation did not seem to reliably predict fluid responsiveness (AUC 0.71, Sn 71%, Sp 75%) [14]; however, this review also acknowledged high study heterogeneity.

Below are a few best practices when using the IVC assessment in your clinical care:

  • Avoid using the IVC in isolation. It is a data point in the overall clinical picture of your patient.
  • IVC size is most likely helpful at the extremes (completely plethoric or completely collapsing).
  • Serial (repeated) IVC assessments can help evaluate the patient’s response to your interventions.

Case Resolution

Your cardiac POCUS (5 videos below) shows severe left ventricular dysfunction and dilation.


PSLA view

PSSA view

A4CH view

SUBX view

IVC view

The chest X-ray shows cardiomegaly with pulmonary edema. Labs are notable for severe hypocalcemia to 4.2 mg/dL (thought to be secondary to congenital hypoparathyroidism in the setting of 22q11 syndrome). The labs are otherwise unremarkable.

You suspect his cardiac dysfunction is secondary to severe hypocalcemia, give him calcium gluconate, and emergently transfer him to the nearest pediatric center with cardiac intensive care.

Note: The IVC view does have some respiratory variation, although we more commonly see a plethoric IVC in the setting of heart failure. This is a reminder to avoid making decisions based solely on the IVC view. It’s an extra data point in the overall context of the other POCUS views.

Learn More…

References

  1. Mannarino S, Bulzomì P, Codazzi AC, et al. Inferior vena cava, abdominal aorta, and IVC-to-aorta ratio in healthy Caucasian children: Ultrasound Z-scores according to BSA and age. J Cardiol. 2019;74(4):388-393. https://doi.org/10.1016/j.jjcc.2019.02.021
  2. Marbach JA, Almufleh A, Di Santo P, et al. A Shifting Paradigm: The Role of Focused Cardiac Ultrasound in Bedside Patient Assessment. Chest. 2020;158(5):2107-2118. PMID: 32707179 DOI: 10.1016/j.chest.2020.07.021
  3. Miller AF, Arichai P, Gravel CA, et al. Use of Cardiac Point-of-Care Ultrasound in the Pediatric Emergency Department. Pediatr Emerg Care. 2022;38(1):e300-e305. doi:10.1097/PEC.0000000000002271
  4. Hoffmann RM, Neal JT, Arichai P, et al. Test Characteristics of Cardiac Point-of-Care Ultrasound in Children With Preexisting Cardiac Conditions. Pediatr Emerg Care. 2024;40(4):307-310. doi:10.1097/PEC.0000000000003050
  5. Arnoldi S, Glau CL, Walker SB, et al. Integrating Focused Cardiac Ultrasound Into Pediatric Septic Shock Assessment. Pediatr Crit Care Med. 2021;22(3):262-274. doi:10.1097/PCC.0000000000002658
  6. Kwan C, Weerdenburg K, Pusic M, et al. Learning Pediatric Point-of-Care Ultrasound: How Many Cases Does Mastery of Image Interpretation Take?. Pediatr Emerg Care. 2022;38(2):e849-e855. doi:10.1097/PEC.0000000000002396
  7. Thomas-Mohtat R, Sable C, Breslin K, et al. Interpretation errors in focused cardiac ultrasound by novice pediatric emergency medicine fellow sonologists. Crit Ultrasound J. 2018;10(1):33. Published 2018 Dec 9. doi:10.1186/s13089-018-0113-4
  8. Hamad A, Ng C, Alade K, D’Amico B, et al. Diagnosing Acute Heart Failure in the Pediatric Emergency Department Using Point-of-Care Ultrasound. J Emerg Med. 2021 Sep;61(3):e18-e25. doi: 10.1016/j.jemermed.2021.03.015. Epub 2021 Jun 4. PMID: 34092442.
  9. Scott C, Alade K, Leung SK, Vaughan RM, Riley AF. Cardiac Point-of-Care Ultrasound and Multi-Disciplinary Improvement Opportunities in Acute Systolic Heart Failure Management in a Pediatric Emergency Center. Pediatr Cardiol. 2024;45(6):1353-1358. doi:10.1007/s00246-023-03125-w
  10. Ng L, Khine H, Taragin BH, Avner JR, Ushay M, Nunez D. Does bedside sonographic measurement of the inferior vena cava diameter correlate with central venous pressure in the assessment of intravascular volume in children?. Pediatr Emerg Care. 2013;29(3):337-341. doi:10.1097/PEC.0b013e31828512a5
  11. Modi P, Glavis-Bloom J, Nasrin S, et al. Accuracy of Inferior Vena Cava Ultrasound for Predicting Dehydration in Children with Acute Diarrhea in Resource-Limited Settings. PLoS One. 2016;11(1):e0146859. Published 2016 Jan 14. doi:10.1371/journal.pone.0146859
  12. Via G, Tavazzi G, Price S. Ten situations where inferior vena cava ultrasound may fail to accurately predict fluid responsiveness: a physiologically based point of view. Intensive Care Med. 2016;42(7):1164-1167. https://doi.org/10.1007/S00134-016-4357-9
  13. Orso D, Paoli I, Piani T, Cilenti FL, Cristiani L, Guglielmo N. Accuracy of Ultrasonographic Measurements of Inferior Vena Cava to Determine Fluid Responsiveness: A Systematic Review and Meta-Analysis. J Intensive Care Med. 2020;35(4):354-363. https://doi.org/10.1177/0885066617752308

Additional Reading

  • Marbach JA, Almufleh A, Di Santo P, et al. Comparative Accuracy of Focused Cardiac Ultrasonography and Clinical Examination for Left Ventricular Dysfunction and Valvular Heart Disease: A Systematic Review and Meta-analysis. Ann Intern Med. 2019;171(4):264-272. doi:10.7326/M19-1337
By |2025-05-20T23:09:38-07:00May 21, 2025|Cardiovascular, Pediatrics, PEM POCUS|
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PEM POCUS Series: Soft Tissue Ultrasound

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric soft tissue ultrasonography. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Case Goals

  1. List the indications of performing a pediatric soft tissue point-of-care ultrasound (POCUS).
  2. Describe the technique for performing soft tissue POCUS.
  3. Interpret signs of cellulitis, abscess, and soft tissue foreign body on POCUS.
  4. Describe the limitations of soft tissue POCUS.
  5. Differentiate abscess from other soft tissue pathologies such as cysts and lymph nodes.

Case Introduction: Child with abdominal pain

Wendy is a 7-year-old girl who comes into the emergency department with redness, swelling, and pain on her left calf. Her symptoms started 1 week ago as a scratch which progressively got more red and painful. There has been no drainage from the lesion. She has had no fevers, but endorses elevated temperatures of 99 F.

On arrival, her vital signs are:

Vital SignFinding
Temperature100.1 F
Heart Rate95 bpm
Blood Pressure105/68
Respiratory Rate20
Oxygen Saturation (room air)100%

On her exam, you notice a 3 x 3 cm area of erythema and induration on her right calf with questionable fluctuance. The area is tender to palpation. She has no other skin findings noted, and she is able to bear weight. Given your concern for an abscess which may require drainage, a POCUS is performed.

Pediatric Soft Tissue POCUS

Figure 1. Linear ultrasound transducer

Probe

  • Use a linear, high-frequency transducer.

Technique

  • Hold the probe perpendicular to the skin.
  • Scan the area of interest in 2 orthogonal (perpendicular) planes.
  • If there is an abscess:
    • Measure the abscess in 3 dimensions.
    • Use color Doppler to ensure the structure is not vascular.

Pro Tips

  • It is often helpful to ultrasound the unaffected side as a comparison.
  • You cannot see what you didn’t scan. Scan the entirety of the affected area in 2 planes.
  • Be aware of the patient’s comfort throughout the examination.
  • A water bath may be helpful to visualize lesions in extremities such as the hands or feet.
    • The probe sits just below the water’s surface and does not need to contact the skin.
    • The benefits of using a water bath include better visualization of superficial structures and alleviates the need for direct skin contact.
waterbath technique with ultrasound image

Figure 2. Left: Water bath technique; Right: Ultrasound of a toe using a water bath (image courtesy of The Pocus Atlas and Moudi Hubeishy, MD)

soft tissue layers ultrasound

Figure 3. Normal soft tissue layers on ultrasound (image courtesy of The Pocus Atlas)

Normally on a soft tissue ultrasound, you will see layers of defined structures separated by fascial planes.

  1. Epidermis/dermis: This is the topmost layer and has an hyperechoic appearance on ultrasound.
  2. Subcutaneous tissue: This deeper layer will appear slightly more hypoechoic.
  3. Muscular layer: This even deeper layer classically appears striated in the long axis view, while in the short axis view, it will have a speckled appearance.
  4. Bone: This layer appears hyperechoic cortex with posterior shadowing.

Cellulitis has a spectrum of appearances on ultrasound. Early cellulitis may present as skin thickening (Figure 4).

pem pocus cellulitis hazy thickening

Figure 4. Cellulitis with skin thickening

 

As cellulitis progresses, there is effacement of the clearly differentiated structures seen above, and the tissue layers may appear hazy and hyperechoic. More advanced cellulitis may have “cobblestoning” which is the result of edematous fluid separating fat globules in the subcutaneous tissue.

pem pocus cellulitis cobblestoning

Figure 5. Cellulitis with cobblestoning

 

Video 1. Ultrasound showing cellulitis with cobblestoning

Abscesses can have varied appearances. They can be anechoic (black) or filled with debris leading to a heterogeneous appearance of contents. The rim may be echogenic or blend in with surrounding tissue. They may be well-circumscribed or may have irregular borders.

A. Abscess with irregular borders and heterogeneous appearance

B. Well-circumscribed abscess with heterogeneous debris

C. Larger abscess with well-circumscribed borders

D. Abscess with irregular borders and surrounding cellulitis

E. Abscess with irregular borders and more homogenous appearance

F. Superficial abscess with well-circumscribed borders

Table 1. Examples of different appearances of abscesses on ultrasound
Video 2. Ultrasound of a cutaneous abscess

Color Doppler Flow

Placing color Doppler flow on a suspected abscess is helpful to differentiate it from a lymph node or blood vessel (see “Abscess Mimickers” section for lymph node examples). It may also aid in identifying nearby vasculature.

Figure 6. Abscess with color Doppler flow

Video 3. Ultrasound of cutaneous abscess with color Doppler flow

Posterior Acoustic Enhancement

Abscesses may exhibit posterior acoustic enhancement, which results in an enhanced transmission of ultrasound waves through a fluid-filled structure. Sometimes the abscess may not be as obvious and appear less anechoic due to debris. A squish (or swirl) sign may be elicited by putting pressure on the region, which will cause movement of the abscess contents. This finding has also been called “pus-talsis”.

Figure 7. Abscess with posterior acoustic enhancement

Video 4. Ultrasound of cutaneous abscess with squish sign

Size Measurement

Abscesses should be measured in 2 planes. Measure depth in 1 plane and length in 2. An easy way to remember this is to measure a plus sign (+) in one view, and a minus sign (-) in the other.

Figure 8. Measurement of abscess in two planes (images courtesy of Dr. Munaza Rizvi)

Lymph Nodes

Lymph nodes appear as ovid and well-circumscribed structures on ultrasound and may be confused for abscesses. They may be differentiated by their homogenous echotexture, central echogenic hilum. When inflamed, they may exhibit internal vascularity which should not be seen in an abscess.

Figure 9. A lymph node with a hilum (left) and a reactive inguinal lymph node with central vascularity (right)

Cysts

Cysts are fluid-filled, well-circumscribed structures which may be similar to abscesses. A common soft tissue cyst is an epidermoid cyst, which is a subepidermoid nodule filled with keratin. In addition to physical exam clues which may help distinguish cysts from abscess, cysts are typically very well-circumscribed and more homogenous in appearance.

Figure 10. Epidermoid cyst (image courtesy of The Pocus Atlas and Dr. Robert Jones)

Soft tissue foreign bodies are a common pediatric presentation and can be easily identified on ultrasound. X-rays can be used to identify foreign bodies; however, their use is limited to radiopaque objects. On ultrasound, foreign bodies often appear as a hyperechoic defect.

Figure 11. Hyperechoic foreign body (glass) embedded in the soft tissue of a foot with posterior shadowing

Video 5. Ultrasound of soft tissue foreign body

Foreign bodies embedded for a prolonged time may have signs of infection, such as cellulitis or abscess (Figure 12).

Figure 12. Wooden splinter embedded in a patient’s plantar foot with surrounding fluid collection consistent with abscess

A foreign body’s composition can affect how it appears on ultrasound. Different materials can produce characteristic ultrasound artifacts.

Foreign BodyUltrasound FindingsUltrasound Image
WoodHyperechoic with posterior shadowing
GlassHyperechoic with posterior shadowing
May have comet tail artifact

Images courtesy of Dr. Ashkon Shaahinfar

MetalVery hyperechoic
Often has a comet tail or reverberation artifact
Table 2. Foreign body characteristics on ultrasound

Foreign Body Removal

Ultrasound assistance in foreign body removal may be static (used to locate the foreign body’s position) or dynamic (using ultrasound to guide foreign body removal in real-time). Measuring the foreign body and assessing the object’s depth on ultrasound may assist in determining if bedside removal versus surgical removal is indicated.

Limited evidence suggests that there may be some sonographic differences between the papular urticaria of a “skeeter syndrome” and local cellulitis. On ultrasound, both findings will have thickening of dermal and subcutaneous tissues. Angioedema characteristically includes more linear, horizontal, striated bands — in comparison to cobblestoning found in cellulitis [1]. However, additional studies are needed to confirm this.

Figure 13. Ultrasound of angioedema (left) and cellulitis with cobblestoning (right). Angioedema image courtesy of Dr. Laura Malia.

Necrotizing fasciitis is a rare pediatric diagnosis but a rapidly progressive and life-threatening condition if not identified quickly. While necrotizing fasciitis is primarily a clinical diagnosis, imaging may be helpful when the diagnosis is uncertain. Computed tomography (CT) and magnetic resonance imaging (MRI) have good test characteristics; however, these tests are time-consuming and may not be available in all centers. CT also involves ionizing radiation. Point-of-care ultrasound has the benefit of rapid bedside use and lack of ionizing radiation.

On ultrasound, early necrotizing fasciitis presents with thickening of the subcutaneous tissue, similar to cellulitis. Fluid in the fascial layers may also be present, and a thick layer of pre-fascial fluid >4 mm has been associated with necrotizing fasciitis [2]. Subcutaneous air with dirty shadowing (Figure 14) is a characteristic but late finding in necrotizing fasciitis. These findings may be recalled using the “STAFF” mnemonic [3]:

  • Subcutaneous Thickening
  • Air
  • Fascial Fluid

Note: It may be difficult to distinguish early cases of necrotizing fasciitis from cellulitis. Therefore ultrasound should not be used to exclude necrotizing fasciitis. Patients with findings concerning for necrotizing fasciitis require additional work-up and surgical consultation.

Figure 14. Necrotizing fasciitis on POCUS exam showing the presence of air with dirty shadowing within soft tissue (image courtesy of Dr. Di Coneybeare)

For additional reading on ultrasounding necrotizing fasciitis, see these ALiEM articles:

  • As with all ultrasound applications, soft tissue POCUS is operator dependent.
  • The ultrasound can only see what is scanned. You must make sure the lesion is fully imaged.
  • It is difficult to differentiate between various types of fluid on ultrasound. For example, hematomas may resemble abscesses. Therefore clinical context is important.

There have been multiple studies (Table 3) that support the use of soft tissue POCUS for identification of cellulitis or abscess. Soft tissue POCUS has been shown to have good sensitivity and specificity. It has also been shown to be superior to clinical assessment in several pediatric studies.

POCUS can also reduce the length of stay (LOS) for our patients. In one pediatric study including 3,094 children suspected of a soft tissue infection who underwent either POCUS or radiology department ultrasound, POCUS was shown to have a shorter median LOS by 73 minutes (95% CI 52.4-93.6 min) [4].

StudyNMethodsPOCUS Sensitivity (95% CI)POCUS Specificity (95% CI)Conclusions
Gottleib et al., Ann Emerg Med 2020 [5]2,656Systematic review of adult and pediatric studies94.6%

(89.4-97.4%)

85.4%

(78.9-90.2%)

POCUS has good diagnostic accuracy. Led to correct change in management in 10% of cases.
Lam et al., J Emerg Med 2018 [6]327Prospective cohort study of children 6mo-18yrs comparing clinical assessment to POCUS90.3%

(83.4-94.7%)

80%

(70.0-87.4%)

POCUS changed management in 22.9% of cases*
Subramaniam et al., Acad Emerg Med 2016 [7]800Systematic review of adult and pediatric (patients from birth – 21yrs) studies97%

(94-98%)

83%

(75-88%)

POCUS may assist physicians in distinguishing cellulitis versus abscess.
Adams et al., J Pediatr 2015 [8]151Prospective cohort study of patients 3mo-21yrs comparing clinical assessment to POCUS96%

(90-99%)

87%

(74-95%)

POCUS changed management in 27% of cases.** For every 4 ultrasounds performed, 1 correct change in management.
Sivitz et al., J Emerg Med 2009 [9]50Prospective cohort study of children <18yrs comparing clinical assessment to POCUS90%

(77-100%)

83%

(70-97%)

POCUS changed management in 22% of cases.
Table 3. Studies comparing soft tissue POCUS to clinical assessment in the management of soft tissue infections.
* Change in management after POCUS defined by the following:
  • Changed incision location/size
  • Added packing
  • Medical to surgical management
  • Surgical to medical management
  • Consultation of specialist
  • Other
** Change in management defined as when the ultrasound diagnosis was discordant from the physical exam and matched the ultimate lesion classification.

Case Resolution

After reviewing the literature, you decide to perform a POCUS to evaluate for skin abscess. You place a linear, high-frequency transducer over the patient’s affected area and you observe the following:

Video 6. Soft tissue ultrasound showing an abscess with heterogeneous appearance and irregular borders with posterior acoustic enhancement, surrounding soft tissue haziness, cobblestoning

ED Course

The patient underwent successful incision and drainage of the abscess, and she was discharged home with antibiotics.

 

Learn More…

References

  1. Tay ET, Ngai KM, Tsung JW, Sanders JE. Point-of-Care Ultrasound on Management of Cellulitis Versus Local Angioedema in the Pediatric Emergency Department. Pediatr Emerg Care. 2022 Feb 1;38(2):e674-e677. doi: 10.1097/PEC.0000000000002416. PMID: 34398861.
  2. Yen ZS, Wang HP, Ma HM, et al. Ultrasonographic screening of clinically-suspected necrotizing fasciitis. Acad Emerg Med. 2002;9:1448–1451. PMID 12460854.
  3. Castleberg E, Jenson N, Dinh VA. Diagnosis of necrotizing faciitis with bedside ultrasound: the STAFF Exam. West J Emerg Med. 2014 Feb;15(1):111-3. doi: 10.5811/westjem.2013.8.18303. PMID: 24578776; PMCID: PMC3935782.
  4. Lin MJ, Neuman M, Rempell R, Monuteaux M, Levy J. Point-of-Care Ultrasound is Associated With Decreased Length of Stay in Children Presenting to the Emergency Department With Soft Tissue Infection. J Emerg Med. 2018 Jan;54(1):96-101. doi: 10.1016/j.jemermed.2017.09.017. Epub 2017 Oct 27. PMID: 29110982.
  5. Gottlieb M, Avila J, Chottiner M, Peksa GD. Point-of-Care Ultrasonography for the Diagnosis of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-analysis. Ann Emerg Med. 2020 Jul;76(1):67-77. doi: 10.1016/j.annemergmed.2020.01.004. Epub 2020 Feb 17. Erratum in: Ann Emerg Med. 2022 Jan;79(1):90. PMID: 32081383.
  6. Lam SHF, Sivitz A, Alade K, Doniger SJ, Tessaro MO, Rabiner JE, Arroyo A, Castillo EM, Thompson CA, Yang M, Mistry RD. Comparison of Ultrasound Guidance vs. Clinical Assessment Alone for Management of Pediatric Skin and Soft Tissue Infections. J Emerg Med. 2018 Nov;55(5):693-701. doi: 10.1016/j.jemermed.2018.07.010. Epub 2018 Aug 28. PMID: 30170835; PMCID: PMC6369916.
  7. Subramaniam S, Bober J, Chao J, Zehtabchi S. Point-of-care Ultrasound for Diagnosis of Abscess in Skin and Soft Tissue Infections. Acad Emerg Med. 2016 Nov;23(11):1298-1306. doi: 10.1111/acem.13049. Epub 2016 Nov 1. PMID: 27770490.
  8. Adams CM, Neuman MI, Levy JA. Point-of-Care Ultrasonography for the Diagnosis of Pediatric Soft Tissue Infection. J Pediatr. 2016 Feb;169:122-7.e1. doi: 10.1016/j.jpeds.2015.10.026. Epub 2015 Nov 10. PMID: 26563535.
  9. Sivitz AB, Lam SH, Ramirez-Schrempp D, Valente JH, Nagdev AD. Effect of bedside ultrasound on management of pediatric soft-tissue infection. J Emerg Med. 2010 Nov;39(5):637-43. doi: 10.1016/j.jemermed.2009.05.013. Epub 2009 Aug 8. PMID: 19665335.
By |2024-05-12T22:03:30-07:00May 13, 2024|Expert Peer Reviewed (Clinical), Infectious Disease, Pediatrics, PEM POCUS, Ultrasound|
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PEM POCUS Series: Pediatric Renal and Bladder Ultrasound

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric renal and bladder ultrasonography. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. List the indications for performing a pediatric renal/bladder point-of-care ultrasound (POCUS)
  2. Describe the technique for performing renal/bladder POCUS
  3. Identify hydronephrosis and its appearance at different severities
  4. List the limitations of renal/bladder POCUS
  5. Advanced: Recognize direct and other indirect signs of nephrolithiasis as well as gross renal/bladder structural anomalies such as cysts and masses

Case Introduction: Child with abdominal pain

Serena is a 9-year-old girl who comes into the emergency department complaining of one day of left flank and left lower quadrant pain (LLQ). The pain is intermittent, sharp, severe, and associated with 2 episodes of nonbloody, nonbilious emesis. Her mother denies any fevers, upper respiratory symptoms, sore throat, or diarrhea. She adds that her daughter has complained of 2-3 episodes of dysuria and gross hematuria over the last few days.

On arrival, her vital signs are:

Vital SignFinding
Temperature99 F
Heart Rate115 bpm
Blood Pressure97/50
Respiratory Rate19
Oxygen Saturation (room air)100%

You find her lying on the gurney, uncomfortable appearing, and intermittently crying. She has a normal HEENT, neck, cardiac, respiratory, and back examination. She has no flank tenderness, but she does cry out with palpation of the LLQ and suprapubic areas.

Given her pain with a history of intermittent hematuria and dysuria, you perform a renal and bladder point of care ultrasound (POCUS) examination.

Pediatric Renal and Bladder POCUS

  • Hematuria
  • Flank pain
  • Abdominal distension or palpable mass
  • Anuria, oliguria, or urinary retention
  • Concern for nephrolithiasis
  • Bladder volume assessment prior to urinary catheterization

Probe choice [1]

  • Typically based on the size of the child (Figure 1)
  • If unsure, perform test scans and choose the probe that most effectively provides the desired views and level of detail
ultrasound probe transducers

Figure 1. Ultrasound probes from left to right: linear (nenoates), phased array (infants/younger children), and curvilinear (older children/adolescents)

Pro tips for performing renal/bladder POCUS on a child [1]

  • Addressing potential anxiety leads to a more efficient and comfortable examination.
  • Explain to the parent (and child if old enough), the areas you need to examine.
  • Set up distractions such as toys or videos on a tablet or smartphone
  • When appropriate, demonstrate the probe(s) to the child and apply some ultrasound gel to the back of their hand so they understand it will not be painful.
  • Pre-warmed ultrasound gel is helpful when available.
  • Examine the patient in a position that maximizes comfort and minimizes anxiety.
    • Lay the patient supine when possible. They can lay on the stretcher, or in the parent’s lap if it calms them (Figure 2, left). This is also an optimal position in which the parent can hold a tablet or smart device above the patient’s face as a distractor.
    • If supine positioning is unsuccessful, the patient can be placed upright in their parent’s lap facing away from the sonographer (Figure 2, right). In this position, the parent can hug and hold the patient if needed.
pediatric ultrasound positioning

Figure 2: Patient positioning options: Left (supine) – Patient playing with the distractors during bladder POCUS; Right (upright) – Toddler facing away from sonographer during renal POCUS. Note: Blue dot represents the probe indicator.

Right Kidney (Longitudinal View)

  • Begin in the mid-axillary line around the 10th or 11th intercostal space with the probe marker pointed toward the patient’s head and identify the renal structures (Figure 3).
  • While maintaining probe contact on the skin, tilt it perpendicular to its long axis in each direction (also known as fanning) to assess the entire kidney (Video 1).
Longitudinal view ultrasound right kidney

Figure 3. Longitudinal view of the right kidney: Left – Probe placement in right mid-axillary line; Right – Unlabeled and labeled ultrasound view

Video 1. Longitudinal view of the right kidney

Right Kidney (Transverse View)

  • From the longitudinal view, rotate the probe 90 degrees and fan the probe to assess the entire kidney in the transverse plane (Video 2).
  • Identify the medullary pyramids, calyces, renal cortex, and renal pelvis (Figure 4).
Video 2. Transverse view of the right kidney
right kidney ultrasound transverse view

Figure 4. Transverse ultrasound view of the right kidney with anatomical labels

Left Kidney (Longitudinal View)

  • Place the probe in the left posterior axillary line (the left kidney is slightly more superior and posterior than the right) around the 8th to 10th intercostal space (Figure 5).
  • As performed on the right kidney, identify the relevant structures and fully assess the left kidney by fanning through (Video 3).
left kidney longitudinal ultrasound probe position

Figure 5. Longitudinal view of the left kidney with probe placement in posterior axillary line

Video 3. Longitudinal view of the left kidney

Left Kidney (Transverse View)

  • From the left longitudinal view, rotate the probe 90 degrees. Identify the relevant structures and fully assess the left kidney by fanning through (Video 4).
Video 4. Transverse view of the left kidney

Bladder (Transverse View)

  • With the indicator towards the patient’s right, place the probe on the patient’s midline just above the pubic symphysis and fan the probe downward into the pelvis (Figure 6). The pelvis, the bladder, uterus, prostate, and rectum can be seen in this view (Figure 7).
    • Pro Tip: The bladder is always directly behind the pubic symphysis, so if you cannot locate it, the probe may be too superior. 2
  • Fan through the entire bladder from superior to inferior borders (Video 5).

Figure 6. Probe positioning for transverse view of the bladder

Figure 7. Transvere ultrasound views of the bladder: Left – Uterus identified posteriorly in girl; Right – Prostate identified posteriorly in boy (Images courtesy of Dinh et al.)

Video 5. Transverse view of the bladder

Bladder (Longitudinal/Sagittal View)

  • From the transverse view, rotate the probe 90 degrees clockwise so the indicator is now pointing to the patient’s head.
  • Identify the bladder, bowel gas, uterus or prostate, and rectum (Figure 8). Then fan to scan from one lateral border of the bladder to the other (Video 6).
bladder longitudinal sagittal view

Figure 8. Sagittal view of bladder: Left – Uterus identified posteriorly in girl; Right – Prostate identified posteriorly in boy (Images courtesy of Dinh et al.)

Video 6. Sagittal view of bladder

Formula

Figure 9. Bladder volume calculation per dimension

The bladder’s shape may appear more rounded when it is full or distended. Bladder volume may be assessed prior to urinary catheterization to avoid an unsuccessful catheterization. Many ultrasound machines also have software which can calculate estimated bladder volume based on the above measurements.

Manual Measurement (Figure 10)

  • In the transverse view, measure the width and depth.
  • In the sagittal view, measure the height from the apex to the base.

Figure 10. Bladder measurement example: Left – Transverse view with width (4.35 cm) and depth (3.65 cm); Right – Sagittal view with height (3.53 cm). Estimated volume = 39.2 mL

Estimated Bladder Capacity by Age

  • [Age of the child (yr) x 30] + 30 = bladder capacity in mL
  • In a toilet-trained child, a post-void volume of ≤20 mL is normal [1].

The scope of POCUS focuses on the detection of hydronephrosis which would necessitate further workup. Hydronephrosis may be secondary to various obstructive etiologies such as nephrolithiasis, masses, or anatomical anomalies.

Severity Grading

Hydronephrosis severity grading begins with dilation at the renal pelvis (grade 1 or pelviectasis), which can be present in normal individuals who have not urinated in some time. The greater the degree of hydronephrosis, the more the dilation extends outwards into the calyces and the renal cortex (Figures 11-15 and Videos 7-9).

Figure 11. Hydronephrosis grading scale (courtesy of Dinh et al.)

Hydronephrosis: Hydroureter

Figure 12. Hydroureter on ultrasound of the right kidney

Hydronephrosis: Mild

Figure 13. Mild hydronephrosis on ultrasound with only pelviectasis, or dilation of the renal pelvis (Image courtesy of Dr. Jim Tsung)

Video 7. Renal ultrasound showing pelviectasis

Hydronephrosis: Moderate

Figure 14. Moderate hydronephrosis showing dilation extending into the major/minor calyces (Image courtesy of POCUS atlas)

Video 8. Moderate hydronephrosis (full video from Figure 14)

Hydronephrosis: Severe

Figure 15. Severe hydronephrosis with dilation causing cortical thinning (Image courtesy of POCUS Atlas)

Video 9. Severe hydronephrosis with “bear claw” sign (full video from Figure 15)

Direct Visualization

Stones may be located anywhere along the urogenital tract. If directly visible, stones will appear as hyperechoic structures and may have acoustic shadowing (Figure 16).

Figure 16. Left – Hyperechoic renal stone with acoustic shadowing and associated moderate hydronephrosis; Right – Bladder stone with acoustic shadowing (images courtesy of Dr. James Tsung)

Video 11. Renal stone with acoustic shadowing and moderate hydronephrosis

Indirect Visualization

Direct visualization will not always be possible since stones are most commonly located in the ureters and may be obscured by bowel gas. Indirect signs of stones include hydronephrosis, twinkling artifact, and absence of ureteral jet [1, 4].

Twinkling artifact is a color Doppler finding that can help identify a stone that may not be directly visible in B-mode. It is generated from turbulent flow around a rough-edged structure (i.e, a stone). Color Doppler interrogation will produce a multi-colored high high-intensity structure behind the stone (Figure 17). The turbulent flow depicted can be seen even if the causative hyperechoic stone is not visible [1, 3].

Figure 17. Twinkling artifact in a patient with a right ureterovesciular junction stone (Image courtesy of Dr. James Tsung)

Video 12. Twinkling artifact from a renal stone

Caution

The scope of renal POCUS is primarily for identifying hydronephrosis, as supported by the literature (see below). However, incidental abnormalities may be noted, such as a renal cyst. Additional work-up is recommended per clinician judgment.

Renal cysts are thin-walled, smooth, localized, and anechoic areas that are round or oval in shape. They can occur as solitary lesions or multiple lesions often in the periphery of the kidney (Figures 18-19). They should not be confused with dilated medullary pyramids from hydronephrosis, which appear as branching and “interlinked” hypoechoic areas resembling a cauliflower. Cysts will have a more spherical shape and will not “communicate” with one another [5].

Figure 19. Single renal cyst without (left) and with (right) color Doppler flow to differentiate from vasculature (Images courtesy of Dr. Jeffrey Tutman)

Figure 20. Multiple renal cysts without (left) and with (right) color Doppler flow differentiating from vasculature  (Images courtesy of Dr. Jeffrey Tutman)

Caution

The scope of renal POCUS is primarily for identifying hydronephrosis, as supported by the literature (see below). However, incidental abnormalities may be noted, such as a masses. Additional work-up is recommended per clinician judgment.

Hyperechoic and heterogeneous lesions that distort or do not conform to typical renal architecture are concerning for renal masses. Wilms tumor is the most common renal malignancy in children with peak incidence between ages 1 and 5 years old. On ultrasound, it appears as an echogenic intrarenal mass that may have cystic areas from hemorrhage and necrosis (Figure 21) [4].

Figure 21. Wilms tumor in the right kidney without (left) and with (right) color Doppler flow (Images courtesy of Dr. Jeffrey Tutman)

Other potential neoplasms within or adjacent to the genitourinary system include but are not limited to neuroblastoma, rhabdoid tumor, rhabdomyosarcoma, renal cell carcinoma, and clear cell carcinoma [4, 6]. The most common malignant bladder mass is rhabdomyosarcoma, and the genitourinary tract is the second most common tumor site. It is usually large, nodular, well-defined, homogeneous, and slightly hypoechoic (Figure 13) [6].

Figure 22. Bladder rhabdomyosarcoma tumor without (left) and with (right) color Doppler flow (Images courtesy of Dr. Jeffrey Tutman)

  • Always scan both kidneys for comparison
  • Scan the bladder when evaluating the kidneys
  • Rib shadowing – attempt to maneuver around rib shadows by reangling the probe or moving up or down a rib space.
  • Bladder dimension calculations may be inaccurate if the calipers are not placed in the right orientations.
  • Large ovarian cysts may be mistaken for the bladder.
  • Because renal stones can be difficult to visualize directly, look for secondary signs such as hydronephrosis.
  • Because renal vasculature may be mistaken for hydronephrosis, use color Doppler to differentiate.
  • Renal cysts can be confused for hydronephrosis, and both warrant further imaging by Radiology.

Bladder volume estimation

Measuring bladder volume via POCUS in pediatric patients has been studied, demonstrating a benefit on Emergency Department workflow and length of stay (Table 1). For example, POCUS can confirm urine in the bladder, prior to catheterization in infants [7-8].

Author, Title, Journal, Publication YearStudy Type, Location, Time FrameN, AgesSummary
Milling et al., Use of ultrasonography to identify infants for whom urinary catheterization will be unsuccessful because of insufficient urine volume: validation of the urinary bladder index. Ann Emer Med, 2005 [7]Prospective, blinded, observational study performed in the pediatric ED, 3 month periodN=44, < 2 years of age
  • Created a bladder urinary index by multiplying the AP and transverse bladder diameters.
  • Determined the smallest bladder index that would result in successful urinary catheterization, which was defined as yielding at least 2 mL of urine.
  • The index achieved 100% sensitivity and 97% specificity.
Chen et al., Utility of bedside bladder ultrasound before urethral catheterization in young children. Pediatrics, 2005 [8]Prospective 2 -hase study, performed in the pediatric ED, 6 month periodN=136 for observation phase

N=112 for intervention phase

Ages 0-24 months

  • Observation Phase: The success rate of the first urethral catheterization attempt was calculated without preemptive bladder ultrasound
  • Intervention Phase: Bladder POCUS was performed, and catheterization was withheld until sufficient urine was present.
  • Successful catheterization rate during the observation phase was 72% overall, compared to 96% in the intervention phase.
Dessie et al., Point-of-Care Ultrasound Assessment of Bladder Fullness for Female Patients Awaiting Radiology-Performed Transabdominal Pelvic Ultrasound in a Pediatric Emergency Department: A Randomized Controlled Trial. Ann Emerg Med, 2018 [9]Randomized controlled trial, performed in a pediatric ED, 12 month periodN=120

8-18 years

  • To assess bladder fullness prior to transabdominal pelvic ultrasound, patients were randomized to subjective numerical scale versus bladder POCUS in addition to numerical scale.
  • Those in the bladder ultrasound arm completed their pelvic ultrasounds 51 minutes faster than the control group.
  • Success rate of pelvic ultrasound was 100% vs 84.7% in the control group.
Table 1. Pediatric bladder POCUS studies

Pediatric Hydronephrosis and Nephrolithiasis

Although adult studies (Table 2) have shown moderate diagnostic accuracy of POCUS in detecting hydronephrosis and nephrolithiasis, there is a dearth of POCUS-based renal studies in the pediatric literature . This has led to controversy whether to perform a renal ultrasound versus CT, even when the Radiology department performs the ultrasound.

  • Only 2 case series and 1 case report for POCUS-identified nephrolithiasis in children (Table 3)
  • No studies have aimed to determine sensitivity and specificity of POCUS for hydronephrosis in children in the context of renal colic.
Author, Title, Journal, Publication YearStudy Type, Location, Time FrameN, AgesSummary
Pathan et al., Emergency Physician Interpretation of Point-of-care Ultrasound for Identifying and Grading of Hydronephrosis in Renal Colic Compared With Consensus Interpretation by Emergency Radiologists, Acad Emerg Med, 2018 [10]Secondary analysis of images, obtained 2014-2015 from a large volume ED.N=651, Adults
  • Secondary analysis of ED physician POCUS images diagnosing hydronephrosis
  • Images were re-interpreted by radiologists to determine accuracy.
  • Sensitivity=85.7%, specificity=65.9%
  • CT was used as a reference standard when possible, yielding sensitivity=81.1% and specificity=59.4%.
Wong et al., The Accuracy and Prognostic Value of Point-of-care Ultrasound for Nephrolithiasis in the Emergency Department: A Systematic Review and Meta-analysis. Acad Emerg Med, 2018 [11]Systematic review & Meta-analysis, Multicenter, 2005 Through April 2016N=1,773, Adults
  • POCUS has modest diagnostic accuracy in adults for nephrolithiasis.
  • Moderate or greater hydronephrosis was highly specific for stones.
  • Detection of any hydronephrosis was suggestive of a stone >5 mm in size.
Kim et al., Usefulness of Protocolized Point-of-Care Ultrasonography for Patients with Acute Renal Colic Who Visited Emergency Department: A Randomized Controlled Study. Medicina, 2019 [12]Prospective randomized control trial in a tertiary care ED, March 2019-July 2019N=164, Adults
  • Evaluated POCUS protocol in managing patients with renal colic in the ED.
  • Patients were assigned to CT vs ultrasound group.
  • Length of stay was 62 min shorter and medical cost was lower in the ultrasound group with no difference in complications within 30 days.
Sibley et al., Point-of-care ultrasound for the detection of hydronephrosis in emergency department patients with suspected renal colic. Ultrasound J, 2020 [13]Prospective observational study in 2 Canadian academic EDs, April 2011 – July 2013N=413, Adults
  • Patients presenting with renal colic had an ED-performed POCUS.
  • The patients also had a CT or an ultrasound by Radiology as a reference standard.
  • For detecting hydronephrosis via POCUS, sensitivity=77.1% and specificity=71.8%.
Table 2. Adult POCUS studies on hydronephrosis and nephrolithiasis
Author, Title, Journal, Publication YearStudy Type, Location, Time FrameN, AgesSummary
Chandra et al., Point-of-care ultrasound in pediatric urolithiasis: an ED case series. Am J Emerg Med. 2015 [14]Case series in a pediatric ED, over a 2-year periodN=8

5-17 years

  • 8 cases of nephrolithiasis were identified with POCUS in patients presenting with renal colic.
  • All patients had confirmatory imaging in radiology.
  • Stones of 2 patients were visualized directly; others were identified by hydronephrosis, twinkling artifact, unilateral absence of ureteral jet, and/or a bladder bulge
Ng et al., Avoiding Computed Tomography Scans By Using Point-Of-Care Ultrasound When Evaluating Suspected Pediatric Renal Colic. Ultrasound in EM, 2015 [15]Retrospective case series in a pediatric ED, time frame not specifiedN=5

3-21 years

  • Hydronephrosis, ureteral jets, twinkling artifact, and the visualization of urinary tract stones were identified in patients with renal colic.
  • CT was avoided in all 5 patients.
Gillon et al., Diagnosis of Posterior Urethral Valves in an Infant Using Point-of-Care Ultrasound. Ped Emerg Care, 2021 [16]Case report in a tertiary pediatric ED, date not specified1, infant
  • Case report of 7-week old boy diagnosed with posterior urethral valves when the ED POCUS identified signs of bladder outlet obstruction. This included a thickened and distended bladder with bilateral hydroureter, severe bilateral hydronephrosis, and small perinephric fluid collections consistent with calyceal rupture.
Table 3. Pediatric POCUS studies on hydronephrosis and nephrolithiasis

Case POCUS

Using the curvilinear probe, you perform a POCUS on the bladder and both kidneys (Video 12).

Video 12. Bilateral renal ultrasound demonstrating twinkling artifact in the bladder and left-sided moderate hydronephrosis, indicative of a distal left ureteral stone (Video courtesy of Dr. Jim Tsung)

Case Resolution

Labs showed a slight leukocytosis with a serum WBC of 13 x109/L but no left shift and a normal creatinine. Urinalysis was positive for blood, RBC’s, and crystals but negative for glucose, ketones, leukocyte esterase, nitrites, WBC’s, squamous cells, and bacteria. The pain and vomiting were well-controlled with ketorolac and ondansetron, respectively. Urology was consulted and recommended medical management. The patient was discharged on tamsulosin and given urine-straining instructions.

Pediatrician Clinic Follow-Up

At her pediatrician clinic visit 2 weeks later, the patient had passed the stone and was asymptomatic.

Learn More…

References

  1. Paliwalla M, Park K. A practical guide to urinary tract ultrasound in a child: Pearls and pitfalls. Ultrasound. 2014 Nov;22(4):213-22. doi: 10.1177/1742271X14549795. Epub 2014 Nov 10. PMID: 27433222; PMCID: PMC4760558.
  2. Deschamps J, Dinh V, Ahn J, et al. Renal Ultrasound Made Easy: Step-By-Step Guide. POCUS101.com. [cited 2023 July 4].
  3. Sethi SK, Raina R, Koratala A, Rad AH, Vadhera A, Badeli H. Point-of-care ultrasound in pediatric nephrology. Pediatr Nephrol. 2023 Jun;38(6):1733-1751. doi: 10.1007/s00467-022-05729-5. Epub 2022 Sep 26. PMID: 36161524; PMCID: PMC9510186.
  4. Milla, Sarah; Lee, Edward; Buonomo, Carlo; Bramson, Robert T. Ultrasound Evaluation of Pediatric Abdominal Masses, Ultrasound Clinics, Volume 2, Issue 3, 2007, Pages 541-559.
  5. Koratala A, Alquadan KF. Parapelvic cysts mimicking hydronephrosis. Clin Case Rep. 2018 Feb 21;6(4):760-761. doi: 10.1002/ccr3.1431. PMID: 29636957; PMCID: PMC5889270.
  6. Shelmerdine SC, Lorenzo AJ, Gupta AA, Chavhan GB. Pearls and Pitfalls in Diagnosing Pediatric Urinary Bladder Masses. Radiographics. 2017 Oct;37(6):1872-1891. doi: 10.1148/rg.2017170031. PMID: 29019749.
  7. Milling TJ Jr, Van Amerongen R, Melville L, et al. Use of ultrasonography to identify infants for whom urinary catheterization will be unsuccessful because of insufficient urine volume: validation of the urinary bladder index. Ann Emerg Med. 2005;45(5):510-513. doi:10.1016/j.annemergmed.2004.11.010
  8. Chen L, Hsiao AL, Moore CL, Dziura JD, Santucci KA. Utility of bedside bladder ultrasound before urethral catheterization in young children. Pediatrics. 2005 Jan;115(1):108-11. doi: 10.1542/peds.2004-0738. PMID: 15629989.
  9. Dessie A, Steele D, Liu AR, Amanullah S, Constantine E. Point-of-Care Ultrasound Assessment of Bladder Fullness for Female Patients Awaiting Radiology-Performed Transabdominal Pelvic Ultrasound in a Pediatric Emergency Department: A Randomized Controlled Trial. Ann Emerg Med. 2018 Nov;72(5):571-580. doi: 10.1016/j.annemergmed.2018.04.010. Epub 2018 Jul 3. PMID: 29980460.
  10. Pathan SA, Mitra B, Mirza S, Momin U, Ahmed Z, Andraous LG, Shukla D, Shariff MY, Makki MM, George TT, Khan SS, Thomas SH, Cameron PA. Emergency Physician Interpretation of Point-of-care Ultrasound for Identifying and Grading of Hydronephrosis in Renal Colic Compared With Consensus Interpretation by Emergency Radiologists. Acad Emerg Med. 2018 Oct;25(10):1129-1137. doi: 10.1111/acem.13432. Epub 2018 May 28. PMID: 29663580.
  11. Wong C, Teitge B, Ross M, Young P, Robertson HL, Lang E. The Accuracy and Prognostic Value of Point-of-care Ultrasound for Nephrolithiasis in the Emergency Department: A Systematic Review and Meta-analysis. Acad Emerg Med. 2018 Jun;25(6):684-698. doi: 10.1111/acem.13388. Epub 2018 Mar 25. PMID: 29427476.
  12. Kim SG, Jo IJ, Kim T, et al. Usefulness of Protocolized Point-of-Care Ultrasonography for Patients with Acute Renal Colic Who Visited Emergency Department: A Randomized Controlled Study. Medicina (Kaunas). 2019 Oct 28;55(11):717. doi: 10.3390/medicina55110717. PMID: 31661942; PMCID: PMC6915595.
  13. Sibley S, Roth N, Scott C, et al. Point-of-care ultrasound for the detection of hydronephrosis in emergency department patients with suspected renal colic. Ultrasound J. 2020 Jun 8;12(1):31. doi: 10.1186/s13089-020-00178-3. PMID: 32507905; PMCID: PMC7276462.
  14. Chandra A, Zerzan J, Arroyo A, Levine M, Dickman E, Tessaro M. Point-of-care ultrasound in pediatric urolithiasis: an ED case series. Am J Emerg Med. 2015 Oct;33(10):1531-4. doi: 10.1016/j.ajem.2015.05.048. Epub 2015 Jun 23. PMID: 26321169.
  15. Ng C, Tsung JW. Avoiding Computed Tomography Scans By Using Point-Of-Care Ultrasound When Evaluating Suspected Pediatric Renal Colic. J Emerg Med. 2015 Aug;49(2):165-71. doi: 10.1016/j.jemermed.2015.01.017. Epub 2015 Apr 29. PMID: 25934378.
  16. Gillon JT, Cohen SG. Diagnosis of Posterior Urethral Valves in an Infant Using Point-of-Care Ultrasound. Pediatr Emerg Care. 2021 Aug 1;37(8):435-436. doi: 10.1097/PEC.0000000000002393. PMID: 34397679
By |2024-03-04T12:54:08-08:00Mar 7, 2024|Expert Peer Reviewed (Clinical), Genitourinary, Pediatrics, PEM POCUS, Renal|
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SAEM Clinical Images Series: Unusual Scalp Lesions

scalp

A 6-year-old male presented to the pediatric emergency department (PED) for scalp lesions. He was seen by his pediatrician 2 weeks prior and prescribed antibiotics and a delousing shampoo for suspected cellulitis versus lice infestation. Symptoms did not improve despite completion of treatment. An outpatient ultrasound was performed showing “multiple scalp echogenic nodular lesions measuring from 0.5 cm to 1.2 cm in the long axis diameter.” The following differential diagnosis was entertained: lymphadenitis, benign avascular mass, epidermal inclusion cyst, or pilomatricoma, and the patient was started on clindamycin. Due to concern for an oncologic process, a surgery consultation was placed to arrange for a biopsy. Four days after the ultrasound and before the biopsy could be performed, the patient and his mother presented to the PED due to worsening symptoms. Multiple new lesions developed across the patient’s scalp which bled when pressure was applied. The patient denied fever and reported intermittent pruritus and pain over the lesion sites. The mother reported a history of travel to Ecuador one month prior to symptom onset.

Vitals: BP 98/61; Pulse 73; Temp 36.3°C (97.3°F) temporal; Resp 18; SpO2 99%, RA

Skin: Large, 3 x 3cm indurated, erythematous lesion located over the patient’s right temporal scalp (Image 1). Five additional lesions noted across the entirety of the scalp. No lesions identified below the neck. Lesions are mildly tender to palpation; no fluid able to be expressed. A small centrally located pore is noted on each lesion with appearance of pulsatile fluid level. No associated lymphadenopathy. A point-of-care ultrasound (POCUS) using a high-frequency, linear transducer was performed during the PED visit (Image 2).

Non-contributory

In short axis, there is an echogenic lesion with surrounding fluid (halo sign) suggesting a foreign body that also exhibits posterior acoustic shadowing. With the transducer held still, independent movement is visualized within the center of the lesion (Image 3).

Cutaneous furuncular myiasis due to Dermatobia hominis (botfly infestation).

Take-Home Points

  • Native to Central and South America, botfly infestation is facilitated through an infected female mosquito which deposits its eggs on the skin of a mammal on which it feeds.
  • Cutaneous furuncular myiasis is important to consider for unexplained head, neck, and extremity lesions when there is suspected travel to endemic areas and is unlikely to be recognized in the continental United States due to low prevalence.
  • Consider pertinent physical exam findings and utility of POCUS in confirming the diagnosis.

  • Harris AT, Bhatti I, Bajaj Y, Smelt GJ. An unusual cause of pre-auricular swelling. J Laryngol Otol. 2010 Mar;124(3):339-40. doi: 10.1017/S002221510999082X. Epub 2009 Aug 11. PMID: 19664319.
  • Minakova E, Doniger SJ. Botfly larva masquerading as periorbital cellulitis: identification by point-of-care ultrasonography. Pediatr Emerg Care. 2014 Jun;30(6):437-9. doi: 10.1097/PEC.0000000000000156. PMID: 24892687.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-09-27T08:23:43-07:00Oct 2, 2023|Dermatology, Pediatrics, PEM POCUS, SAEM Clinical Images|
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PEM POCUS Series: Pediatric Lung Ultrasound

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric lung ultrasound. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. List indications for performing a pediatric lung point-of-care ultrasound (POCUS).
  2. Describe the technique for performing lung POCUS.
  3. Recognize anatomical landmarks and artifacts related to lung POCUS.
  4. Interpret signs of a consolidation, interstitial fluid, effusion, and pneumothorax on POCUS.
  5. Describe the limitations of lung POCUS.

Child with Cough and Fever: Case Introduction

A 6-year-old boy presents to the emergency department complaining of cough for 3 days and fever for the last day. His fever was 103°F this morning and he received ibuprofen. He has also had abdominal and back pain. He was seen at the emergency department earlier in the day where he had a chest X-ray 6 hours prior that was interpreted as negative for consolidation and bloodwork including a complete blood count and comprehensive metabolic panel that were within normal limits. He presents with persistent cough and fever and now has increased work of breathing.

On arrival, his vital signs are:

Vital SignFinding
Temperature99.7 F
Heart Rate138 bpm
Blood Pressure102/61
Respiratory Rate32
Oxygen Saturation (room air)100%

He is well appearing but has increased work of breathing. His lungs have decreased breath sounds and crackles over the left lung base. No wheezes are appreciated. He has mild subcostal retractions. His abdomen is soft, non-tender, and non-distended. His back is non-tender to palpation. He has normal HEENT, neck, and cardiac examinations, with the exception of tachycardia as above.

Given his presenting signs and symptoms in the setting of a recent chest X-ray that was interpreted as normal, you decide to perform a lung point-of-care ultrasound (POCUS) examination.

Lung POCUS can be performed for a wide range of cardiorespiratory complaints including cough, fever, difficulty breathing, chest pain, hypoxia, and chest trauma. It can also facilitate early diagnosis, allowing for appropriate management. Children are excellent candidates for lung POCUS as they have thinner chest walls and smaller thoracic widths than adults.

Background

The lungs were traditionally considered poorly accessible to ultrasound, as ultrasound waves cannot penetrate air-filled structures; however, lung POCUS relies on the interpretation of patterns of artifacts to evaluate the normal, air-filled lungs.

When there is lung pathology, the consolidation or fluid allows for direct visualization of the pathology with lung POCUS and replaces the air artifacts. Fluid in a consolidation or effusion is easily visualized with ultrasound if the fluid has direct contact with the pleural surface. As lung POCUS will only visualize the lung under the probe, it is essential to completely evaluate the lungs anteriorly, laterally, and posteriorly to avoid missing pathology.

Technique

Positioning and Probe

lung POCUS comfortable positioning child

Figure 1: Younger children can sit in their parent’s lap and give a hug for lateral and posterior lung scanning.

  • The patient should be in a position of comfort: supine, sitting, or in parent’s lap (Figure 1).
    • Warm gel helps with the child’s comfort.
    • Distractions such as a toy, book, or phone/tablet can also help ease anxiety.
  • Use a linear high frequency probe. If increased depth is needed, such as in the evaluation for effusion, a curvilinear or phased array probe may also be used.

 

Scanning Protocols

There are different protocols to scan the lung depending on the purpose of the evaluation. For example, in pneumothorax, we focus on the anterior chest where air rises in a supine patient, and for the extended Focused Assessment with Sonography (eFAST) exam, we focus on more dependent areas where pleural fluid or blood collects. Below we discuss the complete lung exam which is often used in evaluating for pneumonia.

Lung POCUS anatomy 6-zone scan area

Figure 2: The 6-zone lung scanning protocol includes anterior, lateral, and posterior lung fields bilaterally.

  • A 6-zone lung ultrasound protocol is used for a complete lung examination (Figure 2):
    • Anterior lungs bilaterally are scanned in the mid-clavicular line from the apex to the base of the lungs and diaphragm.
    • Lateral lungs bilaterally are scanned in the mid-axillary line from the apex to the base of the lungs and diaphragm.
    • Posterior lungs bilaterally are scanned medial to the scapulae and lateral to the vertebral bodies from the apex to the base of the lungs and diaphragm.
  • Place the probe longitudinally, perpendicular to the ribs, with the probe marker towards the patient’s head. Identify anatomical landmarks on ultrasound (Figure 3, Video 1).
Lung POCUS A lines normal child

Figure 3: Normal lung with A-lines in longitudinal (left) and transverse (right) orientations

 

Video 1: Normal lung POCUS in longitudinal orientation

 

Video 2: Normal lung POCUS in transverse orientation

Normal Lung Findings

  1. Ribs: Hyperechoic, curvilinear structure with posterior acoustic shadowing
  2. Pleural line: Hyperechoic line immediately deep to the ribs
    • Lung sliding sign: Visceral and parietal pleural are juxtaposed and sliding against each other with respirations, giving the pleural line a shimmering or “ants marching on a log” appearance. For additional examples, see the PEM POCUS Endotracheal Intubation Confirmation article, specifically in Section 2 – Indirect Confirmation: Visualize Bilateral Lung Sliding.
  3. Lungs filled with air: Visualized on POCUS as horizontal A-lines, which are a reverberation artifact of the pleural line. The pleural line is reflected as the ultrasound beams bounce back and forth between the probe and the highly reflective pleural line, and therefore the distance between A-lines is the same as the distance between the probe and the pleural line (Figure 4).
Lung POCUS A lines reverberation normal

Figure 4: Reverberation artifact and A-lines. The probe sends out ultrasound waves that bounce back and forth between the highly reflective pleural line and the probe (leftmost 3 arrows). The ultrasound machine then interprets these signals as A-lines equidistant from the pleural line (rightmost 3 arrows).

Lung POCUS pulmonary consolidation

Figure 5: Pneumonia with sonographic hepatization, air bronchograms, and irregular pleural line

 

Video 3: Lung POCUS showing a pneumonia

 

Consolidation will appear as a subpleural, hypoechoic, irregularly shaped area, which will move with respirations. It can have the following findings on lung POCUS:

  • Hepatization refers to the homogenous, soft tissue echotexture due to fluid in the lung.
  • Shred sign refers to the irregular borders of the non-pleural edge of a pneumonia that is not translobar and thus adjacent to normal lung.
  • Pleural line irregularities refer to the hypoechoic or fragmented pleural line at the consolidation.
  • Hyperechoic air bronchograms are air in the bronchioles (white dots or branches) surrounded by hypoechoic (dark), fluid-filled lung (Figure 5 and Video 3).

Lung POCUS B lines waterfall

Figure 6: Lung POCUS showing B-lines (A) and a confluence of B-lines, known as the waterfall sign (B)

Video 4: Lung POCUS showing a confluence of B-lines (waterfall sign)

B-lines represent interstitial fluid and may arise from viral infection, pulmonary edema, or acute respiratory distress syndrome (ARDS).

  • POCUS appearance:
    • Ring-down artifacts that arise from the pleural line and extend to the bottom of the screen (Figure 6A). They move with lung sliding and erase A-lines at their intersection.
    • More than 3 B-lines in an intercostal space has been considered abnormal in the adult population. However it may not always be feasible to accurately count the number of B-lines.
    • The distribution of B-lines may help differentiate etiologies, with focal B-lines in pneumonia or atelectasis, and diffuse B-lines in pulmonary edema or ARDS.
  • Waterfall sign: A confluence of B-lines (Figure 6B and Video 4)

POCUS lung subpleural consolidation

Figure 7: Lung POCUS with subpleural consolidation

Video 5: Lung POCUS with subpleural consolidation

Subpleural consolidations are small hypoechoic or tissue-like structures with pleural line abnormalities and blurred margins (Figure 7 and Video 5). They measure <1 cm and are usually seen with a viral process.

Lung POCUS pleural effusion

Figure 8: Pleural effusion with linear probe (A) and phased array probe for increased depth (B).

Video 6: Lung POCUS with pleural effusion using linear probe

A pleural effusion is visualized as anechoic (black) fluid between the chest wall and lung or between the diaphragm and lung (Figure 8 and Video 6).

  • Scan the lateral chest in the posterior axillary line in the supine patient, as fluid is dependent and will accumulate posteriorly.
  • The pleural effusion can be fluid in an infectious process or blood in the setting of trauma.

Absent Lung Sliding

Video 7: Lung POCUS showing a pneumothorax with absent lung sliding

In pneumothorax, there is air between the visceral and parietal pleural, so there will be no lung sliding visualized on lung POCUS.

  • Scan for a pneumothorax in the anterior chest in the 2nd-4th intercostal space in the mid-clavicular line in a supine patient, as air will rise to the highest point in the chest.
  • The pleural line will appear as a static, hyperechoic line (Video 7).
  • There will be A-lines visualized, but no B-lines.
    • Pro Tip: The presence of B-lines is highly sensitive against the presence of a pneumothorax in that location.

 

Lung Point

Video 8: Lung POCUS with evidence of a lung point

Lung point, when seen, is the edge of the pneumothorax, where regular lung sliding occurs adjacent to absent lung sliding (Video 8).

  • Lung point is 100% specific for pneumothorax, but it may not be visualize d for a large pneumothorax with lung collapse.

 

Motion (M) Mode

Figure 9: Lung POCUS showing a normal lung with the seashore sign (A) and a pneumothorax with the barcode sign (B)

M-mode may also be used to evaluate for pneumothorax.

  • Normal lung: There will be the seashore sign, with a granular pattern representing aerated, moving lung below the pleural line (Figure 9a).
  • Pneumothorax: There will be a barcode or stratosphere sign, with no aeration or movement below the pleural line (Figure 9b).

Additional examples can be found in the PEM POCUS: Endotracheal Tube Confirmation article in Section 2 – Indirect Confirmation: Visualize Bilateral Lung Sliding.

lung abscess

Figure 10: Lung abscess with adjacent lung consolidation and pleural effusion

 

Lung abscess may also be evaluated by lung POCUS and will have a hypoechoic fluid collection (Figure 10).

  • Consolidated lung and pleural effusion are also commonly seen.
  • Lung ultrasound is more accurate than chest X-ray at evaluating lung abscess.

Lung pathology may be missed without a complete lung POCUS scanning protocol, as you will only see pathology located directly under the probe. The lung POCUS is also operator-dependent, and it has a steep learning curve.

False Negative:

  • POCUS can’t visualize a centrally located pneumonia not extending to the pleural surface. A lung consolidation needs to extend to the pleural surface to be visualized on lung POCUS.
  • However, a study in adult patients showed that 99% of lung consolidations extend to the pleura [1]. Thus, in children with smaller lung mass, most consolidations likely will be detected by lung POCUS.

False Positives:

Left Lower Chest

  • Caution is needed at the left lower chest, as the spleen and air in the stomach can be misinterpreted as consolidation (Figure 11).
  • Locate the diaphragm in the left lower chest to be sure you are evaluating lung above the diaphragm.
stomach spleen

Figure 11: The spleen and the stomach with air may be misinterpreted as consolidation.

Thymus

  • In younger children, the thymus may be misinterpreted as a consolidation.
  • The thymus will be adjacent to the heart, have regular echotexture, no air bronchograms, and regular borders (Figure 12).
thymus

Figure 12: Thymus (*) located adjacent to the heart

 

There have been multiple studies of lung POCUS identifying pneumonia in children, and several meta-analyses have been published [2-4]. Table 1 summarizes these studies, showing an overall high accuracy for lung POCUS diagnosis of pneumonia in children.

StudyNSensitivitySpecificityComments
Pereda et al., Pediatrics 20158 studies; 765 patients

96%

93%

Evidence supports lung POCUS as an alternative for diagnosis of pneumonia in children.
Balk et al., Pediatr Pulmonol 201812 studies; 1510 patients

96%

95%

Lung POCUS had significantly better sensitivity than chest X-ray, which had a sensitivity of 87%.
Tsou et al., Acad Emerg Med 201925 studies; 3353 patients

94%

92%

Significant difference in accuracy between novice and advanced sonographers.
Table 1. Meta-analyses of lung POCUS for diagnosis of pneumonia in children

1. Decreased radiation and length of stay

  • A randomized controlled trial comparing lung POCUS to chest X-ray for diagnosis of pneumonia showed a 39% reduction in chest X-ray utilization and a decreased emergency department length of stay from 180 to 132 minutes in the patients receiving only lung POCUS with no cases of missed pneumonia [5].

2. Best view for pneumonia

  • A study looking at lung consolidation locations in children with pneumonia found that 96% of pneumonias were detected by the transverse view, compared to 86% in the longitudinal view.
  • The authors concluded that the transverse orientation detects more pneumonia than the longitudinal view, and that omission of either orientation or any lung zone may miss pneumonia [6].

3. Pneumothorax: POCUS is better

  • A meta-analysis of chest X-ray vs ultrasound for diagnosis of pneumothorax showed that ultrasound had a sensitivity of 88% and specificity of 99% compared to sensitivity of 52% and specificity of 100% for chest X-ray. Furthermore, lung POCUS performed specifically by non-radiologist clinicians had a sensitivity of 89% and specificity of 99% [7].

Case Resolution

The patient’s chest X-ray from earlier in the day was interpreted by the pediatric radiologist as negative for consolidation or other pulmonary pathology. You performed a lung POCUS with a linear, high-frequency probe and observed the following:

Video 9: A lung POCUS of the case patient’s left lower lung (affected side)

Though this child with cough, fever, focal lung findings, and respiratory distress had a negative chest X-ray performed 6 hours earlier, your POCUS evaluation identified a left lower lobe pneumonia which helped you make your diagnosis and start the appropriate treatment.

ED Course

The patient received antibiotics for pneumonia. His work of breathing increased during his emergency department visit, and he was started on high flow nasal cannula at 30 L/min with improvement in his respiratory status. He was admitted to the pediatric intensive care unit. He had a repeat chest X-ray 12 hours later that was interpreted by the pediatric radiologist as having new pleural and parenchymal changes in the left hemithorax with questionable pneumonia. He continued antibiotics, and his repeat X-ray 48 hours later showed a clear left lower lobe consolidation with pleural effusion.

 

Learn More…

References

  1. Lichtenstein DA, Lascols N, Mezière G, Gepner A. Ultrasound diagnosis of alveolar consolidation in the critically ill. Intensive Care Med. 2004 Feb;30(2):276-281. PMID: 14722643
  2. Pereda MA, Chavez MA, Hooper-Miele CC, et al. Lung ultrasound for the diagnosis of pneumonia in children: a meta-analysis. Pediatrics. 2015 Apr;135(4):714-22. PMID: 25780071
  3. Balk DS, Lee C, Schafer J, et al. Lung ultrasound compared to chest X-ray for diagnosis of pediatric pneumonia: A meta-analysis. Pediatr Pulmonol. 2018 Aug;53(8):1130-1139. PMID: 29696826
  4. Tsou PY, Chen KP, Wang YH, et al. Diagnostic Accuracy of Lung Ultrasound Performed by Novice Versus Advanced Sonographers for Pneumonia in Children: A Systematic Review and Meta-analysis. Acad Emerg Med. 2019 Sep;26(9):1074-1088. PMID: 31211896
  5. Jones BP, Tay ET, Elikashvili I, et al. Feasibility and Safety of Substituting Lung Ultrasonography for Chest Radiography When Diagnosing Pneumonia in Children: A Randomized Controlled Trial. Chest. 2016 Jul;150(1):131-8. PMID: 26923626
  6. Milliner BHA, Tsung JW. Lung Consolidation Locations for Optimal Lung Ultrasound Scanning in Diagnosing Pediatric Pneumonia. J Ultrasound Med. 2017 Nov;36(11):2325-2328. PMID: 28586113
  7. Ding W, Shen Y, Yang J, He X, Zhang M. Diagnosis of pneumothorax by radiography and ultrasonography: a meta-analysis. Chest. 2011 Oct;140(4):859-866. PMID: 21546439

Additional Reading

  • Rizvi MB, Rabiner JE. Pediatric Point-of-Care Lung Ultrasonography: A Narrative Review. West J Emerg Med. 2022 Jun 5;23(4):497-504. PMID: 35980421
By |2024-03-04T12:41:15-08:00Aug 9, 2023|Expert Peer Reviewed (Clinical), Pediatrics, PEM POCUS, Radiology, Ultrasound|
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PEM POCUS Series: Pediatric Focused Assessment with Sonography for Trauma (FAST)

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for Pediatric Focused Assessment with Sonography for Trauma. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. Summarize the indications and role of the FAST in the evaluation of injured children
  2. Describe the technique for performing the pediatric FAST
  3. Identify anatomical views and landmarks necessary for a complete pediatric FAST
  4. Accurately interpret each pediatric FAST anatomic view and corresponding landmarks
  5. Describe the literature on the pediatric FAST

Case Introduction

You receive an emergency medical services (EMS) notification that they are 2 minutes out from your ED with a 3-year-old boy who fell down a flight of 10 concrete stairs. He is awake and breathing spontaneously but irritable and crying with an obvious deformity to his right arm. EMS placed him in a cervical-collar and are bringing him to your ED.

Vital SignFinding
Temperature37.5oC
Heart Rate158 bpm
Blood Pressure86/48
Respiratory Rate32
Oxygen Saturation98% room air

You conduct your primary assessment:

Trauma AlgorithmAssessment
AirwayPatent: Audibly crying; cervical collar in place
BreathingBilateral breath sounds heard
CirculationSymmetric radial pulses palpable bilaterally; capillary refill 2-3 seconds
DisabilityHis eyes are open, but he is irritable and withdraws to touch (GCS= 13)
ExposureDiffuse superficial abrasions to face and extremities; tenderness and swelling to right forearm; abdomen soft without distension although difficult to appreciate tenderness as patient is crying

You call a trauma consult, connect the patient to the monitor, establish IV access, and reach for your ultrasound probe to perform a FAST.

Trauma remains the leading cause of childhood death and disability in children >1 year of age [1]. While head and thoracic trauma account for most death and disability in children, missed abdominal injuries are a common cause of mortality [2]. Particularly in polytrauma scenarios, it can be difficult for children to locate the exact area of pain and assessing for abdominal injury can be difficult.

FAST is a rapid ultrasound examination of 4 locations (Figure 1) with the primary objective of detecting free fluid within the abdomen, pleural space, and pericardial sac. In injured adults, FAST is useful in rapidly triaging hemodynamically unstable patients to expedite operative management [3]. Free fluid in any one view deems the FAST positive. However, for a FAST to be determined as negative, each of the landmarks in each individual view must be interrogated and evaluated for the presence of free fluid. The role of FAST in the hemodynamically stable child after blunt abdominal trauma is nuanced.

FAST ultrasound probe locations surface anatomy

Figure 1. Location of the 4 FAST views: Right upper quadrant (A), left upper quadrant (B), pelvic (C), subxiphoid (D). Illustration by Dr. Maytal Firnberg.

FAST Technique

The FAST can be performed in parallel with the rest of the trauma evaluation. Serial FAST exams can be repeated as needed throughout the child’s ED stay, particularly if the child has an unexplained change in clinical status. For a complete FAST, each of the views needs to be assessed and every landmark in each view must be visualized. In addition to intra-abdominal hemorrhage and pericardial effusion, point-of-care ultrasound can be used to evaluate the thorax for hemothorax and pneumothorax. When included together, this exam is referred to as the extended FAST (E-FAST).

In general, the child should be positioned supine as free fluid will pool in dependent areas (Figure 2). In children, the recto-vesicular or recto-uterine pouch is the most common place for fluid to collect depending on the patient’s sex [4]. Fluid in the abdomen can move freely up the right pericolic gutter into the right upper quadrant. The left pericolic gutter is higher and the phrenicocolic ligament blocks the flow; consequently, fluid tends to flow to the right pericolic area over the left, regardless of injury type.

Some controversy exists about how much free fluid can be detected by the FAST, and most studies focused on adults. For pediatric patients, we are using 100 mL as it was the median quantity of fluid needed for ultrasound detection of the pelvic view [5].

Free fluid collection areas FAST

Figure 2. Free fluid accumulates in dependent areas. In a supine patient, this is the hepato-renal pouch (right upper quadrant view), the spleno-renal pouch (left upper quadrant view), and recto-vesicular or recto-uterine pouch (pelvic view). Illustration by Dr. Maytal Firnberg.

Use a low frequency ultrasound probe: phased array probe (Figure 3) or curvilinear probe (Figure 4).

    • Phased array probes can generally achieve adequate penetration particularly for smaller pediatric patients and have a smaller footprint allowing for easier intercostal views.
    • Curvilinear probes allow for further penetration and greater depth of abdominal views and may be useful in larger children.

In order to obtain each landmark in the views discussed below, the ultrasound probe will often need to be manipulated in a number of orientations.

probe types

Figure 3 (left): Phased array ultrasound probe; Figure 4 (right): Curvilinear ultrasound probe

For the 4 scanning areas, each view must be interrogated completely, and the clinician should identify all key landmarks. The red dot on the probe correlates with the probe marker.

Right ​​Upper Quadrant (RUQ) View
Probe Placement
RUQ probe placement

Figure 5. Place the probe in the right mid axillary line (around ribs 8-10) with the probe marker towards the head. Fan anterior and posterior and slide up or down a rib space to view the key landmarks.

Normal View and Landmarks
RUQ normal ultrasound view

Figure 6. Normal RUQ ultrasound view with labeled landmarks

  • Diaphragm (including the subdiaphragmatic intraperitoneal space and supradiaphragmatic intrathoracic space)
  • Liver (including the caudal tip of the liver)
  • Kidney (including superior and inferior poles)
  • Hepatorenal Recess (Morison’s Pouch) – A potential space between the liver and kidney where free fluid can collect
Normal Ultrasound Video

Video 1. Normal RUQ ultrasound view
Left ​​Upper Quadrant (LUQ) View
Probe Placement
LUQ probe placement

Figure 7. Place the probe in the left mid or posterior axillary line (around ribs 7-9) with the probe maker towards the head. Fan anterior and posterior and slide up or down a rib space to view the landmarks. In infants and smaller children, the midaxillary line generally provides the best view.

Normal View and Landmarks
Normal LUQ ultrasound view

Figure 8. Normal LUQ ultrasound view with labeled landmarks

  • Diaphragm (including the sub- and supradiaphragmatic areas)
  • Spleen (including splenic tip)
  • Kidney (including superior and inferior poles)
  • Splenorenal Recess – a potential space between the spleen and kidney where free fluid can collect
Normal Ultrasound Video

Video 2. Normal LUQ ultrasound view
Pelvic View
Probe Placement
pelvic probe placement

Figure 9. Place the probe in the midline below the umbilicus and fan or rock the probe down towards the feet until the bladder comes into view. Fan through the entire bladder in both transverse and sagittal orientations. For the transverse and sagittal views, the probe marker should be towards the patient’s right and head, respectively.

Normal View and Landmarks
Normal pelvic ultrasound views

Figure 10. Normal sagittal (left) and transverse (right) views of the pelvic ultrasound with labeled bladder

  • Bladder (including anterior and posterior walls)
    • In patients with uteruses, make sure to visualize the uterus and the recto-uterine space as fluid can collect between the bladder and uterus and also behind the uterus.
Normal Ultrasound Video

Video 3. Normal pelvic ultrasound view (sagittal)

Video 4. Normal pelvic ultrasound view (transverse)
Pericardial View
Probe Placement
pericardial ultrasound probe

Figure 11. Place the probe under the sternum for a subxiphoid view. Point the probe towards the left shoulder and the probe marker towards the right shoulder. This view requires gentle downward pressure as you drop the angle of the probe down towards the patient. If unable to obtain this subxiphoid view, look parasternally.

Normal View and Landmarks
Normal pericardial ultrasound view

Figure 12. Normal pericardial subxiphoid ultrasound view with labeled landmarks

  • Hepatic-pericardial interface
  • Left and right ventricles (atria may also be visible)
  • Pericardial space
Normal Ultrasound Video

Video 5. Normal pericardial ultrasound view (no pericardial effusion and normal contractility)

Overarching Goal

The aim of the FAST is to identify free fluid in the abdomen, pelvis, pleural, and pericardial spaces.

Free fluid will appear anechoic (black) and will pool in dependent, unobstructed areas. On the right side, fluid in the abdomen can move freely up the pericolic gutter into the right upper quadrant. On the left, the pericolic gutter is higher and the phrenicocolic ligament may impede its flow. The RUQ view is the most sensitive view in adults while the pelvic view is the most sensitive view in children [4]. The following are examples of free fluid identified within the various views of the FAST scan.

free fluid ultrasound labelled

Figure 13. RUQ ultrasound view demonstrating free fluid in Morrison’s pouch in an unlabelled (A) and labelled (B) image

Abnormal RUQ Views

RUQ Free Fluid ultrasound

Figures 14 (left) and 15 (right). Abnormal RUQ ultrasound views with free fluid. Note that the right image demonstrates free fluid both above and below the diaphragm, meaning fluid that is in the peritoneal and pleural cavities, respectively.

Video 6. Abnormal RUQ ultrasound view with free fluid in the pleural space and Morison’s pouch

Abnormal LUQ Views

Tip: In the LUQ view, the free fluid tends to collect just under the diaphragm. Be sure to look at the diaphragm-spleen interface.

LUQ free fluid ultrasound

Figure 16. Abnormal LUQ view with free fluid below the diaphragm and above the spleen

Video 7. Abnormal LUQ ultrasound view with free fluid under the diaphragm

Abnormal Pelvic Views

Tip: Free fluid can collect between the bladder and colon in male patients. In female patients, fluid can collect between the bladder and uterus or between the uterus and colon.

pelvic free fluid ultrasound

Figure 17. Abnormal pelvic view showing free fluid between the bladder and colon

Video 8. Abnormal pelvic ultrasound on sagittal view showing free fluid

Abnormal Pericardial Views

abnormal pericardial FF ultrasound

Figure 18. Abnormal pericardial view showing pericardial free fluid

Video 9. Abnormal pericardial ultrasound view showing free fluid

ArtifactUltrasound Image
Mirror Artifact

These artifacts are cast above the diaphragm in the RUQ and LUQ views.

ultrasound spine sign artifact

Figure 19. The RUQ view shows liver parenchyma architecture cephalad of the diaphragm as a mirror artifact.

Spine Sign

The spine is not typically seen cephalad to the diaphragm by ultrasound due to air artifact. If the spine is visualized above the diaphragm, this indicates the lungs are no longer filled with air, which normally causes the refraction/reflection of ultrasound waves. This occurs in instances where air is replaced by fluid, such as a pleural effusion or hemothorax, or by a dense consolidation or contusion.

Figure 20. A – The spine is not visualized cephalad to the diaphragm in a normal RUQ ultrasound view. B – A pleural effusion results in a “spine sign” where the spine can be seen extended beyond the diaphragm.

Posterior Acoustic Enhancement

Since the bladder is a fluid filled structure which transmits ultrasound waves well, the waves illuminate the posterior wall of the bladder in a phenomenon called posterior acoustic enhancement. This brightness can hide free fluid settled in the pelvis. Thus, decrease the far field gain (brightness) behind the bladder to avoid missing obscured free fluid.

posterior acoustic enhancement

Figure 21. Bladder view with posterior acoustic enhancement artifact

Old Blood

As blood pools, the ultrasound appearance of clotted blood may have similar echotexture to surrounding soft tissue or organs rather than appear anechoic (black) as typical free fluid.

clotted blood artifact

Figure 22. Bladder view showing hypoechoic clotted blood that may be confused as soft tissue

Edge Artifact

Due to ultrasound physics and sound wave transmission between structures of different densities, edge artifacts are seen as a dark thin line tracing off the edge of this interface extending to the bottom of the screen. It can be misinterpreted as free fluid.

edge artifact ultrasound

Figure 23. RUQ view with an edge artifact

Stomach Sabotage

A full stomach will appear as a rounded collection of fluid and air anterior to the spleen. It may mimic a free fluid collection. Fan posterior of the stomach to visualize the spleen and perisplenic spaces.

Stomach sabotage artifact

Figure 24. The stomach obscures the LUQ view. Note the mix of bright (air) and dark (other gastric contents) inside the stomach.

Seminal Vesicles

Seminal vesicles can appear as hypoechoic, contained, symmetric structures posterior to the bladder in the transverse view and can be mistaken for free fluid.

Seminal vesicle artifact

Figure 25. Bladder view showing hypoechoic seminal vesicles  posterior to the bladder

  • The FAST evaluates for the presence free fluid only [6].
    • In trauma, the assumption is that free fluid is due to hemorrhage; however, the FAST cannot adequately distinguish between blood and other types of free fluid, such as ascites or physiologic free fluid.
    • It does not directly evaluate for injury to solid organs, bowel, diaphragm, or retroperitoneum​.
  • In isolation, the FAST cannot rule out intra-abdominal injury [7].
  • The FAST can not detect tiny amounts of hemorrhage.
    • The scan may appear initially negative with a free fluid volume under a threshold of about 100 mL [5].
    • Repeat FAST scans may help detect an accumulation of fluid over time throughout a child’s evaluation.
  • Trace pelvic free fluid may be physiologic in children, thus limiting specificity [8].

For adults, the FAST is integral in the diagnostic evaluation after blunt and penetrating trauma [9]. It improves outcomesby decreasing the time to surgical intervention, patient length of stay, surgical complications, CT scan, and diagnostic peritoneal lavage rates [3].

For children, however, the literature is less clear cut. Pediatric injury patterns commonly result in solid organ lacerations without hemoperitoneum, making the FAST a less sensitive means for detecting important intra-abdominal injury [7]. Further, the test characteristics of the FAST have variable reliability and accuracy in children [7,10,11]. This variation contributes to uncertainty of how to use results of the FAST and decreases its impact on potentially important clinical outcomes such as rates of CT scans and ED length of stay [12]. However…

  • The FAST is able to identify injuries that the physical exam can miss. When combined with the physical exam, the FAST scan has been found to have better test characteristics than the physical exam alone [13].
  • The improvement in POCUS technology, widespread pediatric-specific POCUS expertise, and a focus on clinically relevant outcomes have allowed clinicians to integrate the FAST into novel diagnostic strategies for children after blunt torso trauma [14].
  • The pediatric FAST may be used in combination with signs, symptoms, and other diagnostic testing as a screening algorithm to decrease unnecessary CTs. Investigators will need to conduct larger validation trials to confirm and clarify the algorithm.

Studies that have shaped the pediatric FAST literature landscape:

StudyStudy Type, Location (Time Frame)N, AgesNotes
Menaker et al., J Trauma Acute Care Surg 2014 [7]

Secondary Analysis of a Prospective Observational Study

Multicenter (May 2007 to January 2010)

6,468

Median age, 11.8 yrs; interquartile range (IQR) 6.3-15.5 yrs

  • Evaluated the variability of clinician-performed FAST examinations and the use of abdominal CT following FAST examination in children with blunt trauma
  • 373 (5.8%) were diagnosed with intra-abdominal injury
  • 3,015 (46.6%) underwent abdominal CT scanning. Only 887 (13.7%) underwent FAST examination before CT scan.
  • Use of the FAST increased as clinician suspicion for intra-abdominal injury increased. When clinicians had a lower suspicion, they were significantly less likely to order a CT scan, if a FAST examination was performed.
Holmes et al., JAMA 2017 [12]

Randomized Clinical Trial

University of California, Davis Medical Center (April 2012-May 2015)

925

Mean 9.7 yrs; SD 5.3 yrs

  • Studied the impact of the FAST scan on on multiple patient centered outcomes
  • Hemodynamically stable patients with blunt torso trauma were randomized a FAST or no FAST scan.
  • 50 had intra-abdominal injury, including 40 patients (80%) with intraperitoneal fluid and 9 patients underwent laparotomy.
  • No difference in the proportion obtaining CT, missed intra-abdominal injuries, length of stay, or cost.
Kornblith et al., Acad Emerg Med 2020 [13]

Retrospective Review

University of California, Benioff Children’s Hospital Oakland (November 2013 to July 2015)

354

Median age 8 yr; IQR 4-12 yr

  • Query of trauma database for children who met institutional trauma activation criteria and who also had a FAST performed.
  • 50 (14%) patients were found to have an intra-abdominal injury with 13 (4%) requiring intervention.
  • Positive FAST and positive physical exam were found to be independent predictors of intra-abdominal injury, both with a 74% sensitivity.
  • When combined, FAST and physical exam (FAST-enhanced physical exam) improved sensitivity to 88% (NPV 97.3%).
Liang et al., Pediatr. Emerg Care 2021 [11]

Systematic Review and Meta-Analysis

Multicenter (January 1966- March 2018)

2,135

Study dependent

  • Based on 8 studies, the FAST had a pooled sensitivity of 35% and specificity 96% for intra-abdomianal injury.
  • All 8 studies were prospective; 1 of the 8 was the 2017 Holmes paper mentioned above [12].
  • Conclusion: For a positive FAST, the post-test probability of an intra-abdominal injury was 63% meaning that those patients should get a CT to characterize injury. If the FAST is negative, you may still need a CT, because the post-test probability of intra-abdominal injury was still relatively high at 9%.
  • None of the studies had low enough negative likelihood ratios to obviate the need for CT.
  • Although a negative FAST alone does not exclude an intra-abdominal injury, it can identify low-risk patients with a reassuring physical exam and GCS 14-15.
Kornblith et al., JAMA 2022 [15]

Expert, consensus–based Modified Delphi

International multicenter (May 2021 to June 2021)

n/a
  • Generated definitions for complete pediatric FAST and E-FAST studies in the context of blunt trauma

Future Directions

The use of FAST in pediatric trauma is an evolving area of active research. A clear consensus on the way the FAST fits into pediatric trauma protocols is yet to be determined. Studies will need to be performed to examine the benefits of serial FAST, patient factors that may influence its test characteristics, and effect on patient centered outcomes.

There are a number of strategies to incorporate the above studies into clinical care, and one example is illustrated in the algorithm below. Keep in mind that FAST should be used in conjunction with other signs and symptoms of intra-abdominal injury (vomiting, decrease breath sounds, abdominal pain, thoracic wall trauma). Also consider laboratory testing such as liver function tests and urinalysis, depending on the clinical context and consulting your surgical colleagues.

Sample Algorithm for Pediatric Blunt Torso Trauma

Zuckerberg San Francisco General Pediatric Blunt Torso Trauma Algorithm (shared with permission)

Case Resolution

The primary survey is completed with airway, breathing, and circulation noted to be intact. As someone starts the secondary survey, you grab a phased array probe and perform a FAST . You observe the following:

RUQ View

LUQ View

Pelvis View, Sagittal

Pelvis View, Transverse

Pericardial View

You call out ‘FAST negative’ to the documenting nurse and team leader.

ED Course

The patient has radiographs performed of his chest, pelvis, neck, and right forearm. He is diagnosed with a type 3 supracondylar humeral fracture but the other radiographs are negative for fracture and pneumothorax. The rest of his evaluation is reassuring. Orthopedics is consulted and they admit him for surgery. He is discharged home the next day with pediatrician follow up.

Pediatrician Clinic Follow-Up

At her pediatrician clinic visit 1 week later, he is playful and active with his arm in a cast. He has been eating and drinking normally without any complaints of abdominal pain. He has orthopedics follow up scheduled for the following week.

Learn More…

References

  1. Leading Causes of Death by Age Group United States 2018. Centers for Disease Control and Prevention. Accessed September 28, 2022
  2. Kenefake ME, Swarm M, Walthall J. Nuances in Pediatric Trauma. Emerg Med Clin North Am. 2013;31(3):627-652. doi:10.1016/j.emc.2013.04.004
  3. Melniker LA, Leibner E, McKenney MG, Lopez P, Briggs WM, Mancuso CA. Randomized controlled clinical trial of point-of-care, limited ultrasonography for trauma in the emergency department: the first sonography outcomes assessment program trial. Ann Emerg Med. 2006;48(3):227-235. doi:10.1016/j.annemergmed.2006.01.008
  4. Brenkert TE, Adams C, Vieira RL, Rempell RG. Peritoneal fluid localization on FAST examination in the pediatric trauma patient. Am J Emerg Med. 2017;35(10):1497-1499. doi:10.1016/j.ajem.2017.04.025
  5. Jehle DVK, Stiller G, Wagner D. Sensitivity in Detecting Free Intraperitoneal Fluid With the Pelvic Views of the FAST Exam.
  6. Netherton S, Milenkovic V, Taylor M, Davis PJ. Diagnostic accuracy of eFAST in the trauma patient: a systematic review and meta-analysis. CJEM. 2019;21(6):727-738. doi:10.1017/cem.2019.381
  7. Menaker J, Blumberg S, Wisner DH, et al. Use of the focused assessment with sonography for trauma (FAST) examination and its impact on abdominal computed tomography use in hemodynamically stable children with blunt torso trauma. J Trauma Acute Care Surg. 2014;77(3):427-432. doi:10.1097/TA.0000000000000296
  8. Berona K, Kang T, Rose E. Pelvic Free Fluid in Asymptomatic Pediatric Blunt Abdominal Trauma Patients: A Case Series and Review of the Literature. J Emerg Med. 2016;50(5):753-758. doi:10.1016/j.jemermed.2016.01.003
  9. Bloom BA, Gibbons RC. Focused Assessment with Sonography for Trauma. In: StatPearls. StatPearls Publishing; 2021. Accessed November 14, 2021.
  10. Holmes JF, Gladman A, Chang CH. Performance of abdominal ultrasonography in pediatric blunt trauma patients: a meta-analysis. J Pediatr Surg. 2007;42(9):1588-1594. doi:10.1016/j.jpedsurg.2007.04.023
  11. Liang T, Roseman E, Gao M, Sinert R. The Utility of the Focused Assessment With Sonography in Trauma Examination in Pediatric Blunt Abdominal Trauma: A Systematic Review and Meta-Analysis. Pediatr Emerg Care. 2021;37(2):108-118. doi:10.1097/PEC.0000000000001755
  12. Holmes JF, Kelley KM, Wootton-Gorges SL, et al. Effect of Abdominal Ultrasound on Clinical Care, Outcomes, and Resource Use Among Children With Blunt Torso Trauma: A Randomized Clinical Trial. JAMA. 2017;317(22):2290-2296. doi:10.1001/jama.2017.6322
  13. Kornblith AE, Graf J, Addo N, et al. The Utility of Focused Assessment With Sonography for Trauma Enhanced Physical Examination in Children With Blunt Torso Trauma. Acad Emerg Med Off J Soc Acad Emerg Med. 2020;27(9):866-875. doi:10.1111/acem.13959
  14. Riera A, Hayward H, Torres Silva C, Chen L. Reevaluation of FAST Sensitivity in Pediatric Blunt Abdominal Trauma Patients: Should We Redefine the Qualitative Threshold for Significant Hemoperitoneum? Pediatr Emerg Care. 2021;37(12):e1012. doi:10.1097/PEC.0000000000001877
  15. Kornblith AE, Addo N, Plasencia M, et al. Development of a Consensus-Based Definition of Focused Assessment With Sonography for Trauma in Children. JAMA Netw Open. 2022;5(3):e222922. Published 2022 Mar 1. doi:10.1001/jamanetworkopen.2022.2922
By |2022-10-12T10:48:28-07:00Oct 7, 2022|Expert Peer Reviewed (Clinical), Pediatrics, PEM POCUS, Radiology, Ultrasound|
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PEM POCUS Series: Pediatric Appendicitis

PEM POCUS pediatric appendicitis

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric appendicitis. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. Describe the indications for performing point-of-care ultrasound (POCUS) for appendicitis
  2. Describe the technique for performing POCUS for appendicitis
  3. Recognize anatomical landmarks for POCUS for appendicitis
  4. Interpret signs of appendicitis on POCUS
  5. List the limitations of POCUS for appendicitis

Case Introduction: Child with thigh pain

Mason is an 8-year-old boy who comes to the emergency department for abdominal pain. The pain has been present for 12 hours, started near his belly button, and now has migrated to the lower right side. He describes it as constant and worsening. His parents are concerned because he had a fever to 101F since 2 hours prior to arrival and had 2 episodes of emesis. They deny diarrhea or bloody stool. They gave acetaminophen for fever 2 hours prior to arrival. He has not wanted to eat anything today.

Vital SignFinding
Temperature37.5 C
Heart Rate120 bpm
Blood Pressure106/58
Respiratory Rate18
Oxygen Saturation (room air)100%

He is uncomfortable appearing, and abdominal examination is soft and tender to palpation periumbilically and in the right lower quadrant. The patient also endorses pain with jumping. Given his history and abdominal pain and tenderness on examination, you are concerned for appendicitis. You place a surgical consult and while waiting, decide to perform a point of care ultrasound (POCUS) examination of the appendix.

Why should I perform the appendix POCUS?

  • Lack of radiation exposure, lower cost, less patient preparation
  • Superior sensitivity and specificity for diagnosing pediatric appendicitis
  • POCUS can save ≥2 hours compared to radiology-performed ultrasound
  • Can help prioritize radiology studies or expedite surgical consult

Limitations of the appendix POCUS

  • Operator dependency and variability in sensitivity
  • Difficult visualization of appendix in retrocecal or aberrant locations
  • Limitation of visualization dependent on patient body habitus
  • Sometimes the appendix cannot be visualized (normal or otherwise)

What are the general principles behind the technique?

  • You are using POCUS to look for an abnormal appendix and/or secondary signs of appendicitis.
  • It is important to recognize anatomical landmarks.
  • The patient should be placed in a supine position.
  • Using the linear transducer is appropriate for most pediatric patients, but if the patient has a larger body habitus, the curvilinear transducer may be used (figure 1).

Figure 1. Linear (left) and curvilinear (right) transducer for ultrasonography

  • Place the probe over the point of maximal tenderness in the abdominal RLQ.
  • Slowly apply increasing gentle pressure (i.e., “graded compression”) to move bowel gas out of the way until able to identify the important landmarks:
    • Iliopsoas muscle
    • Rectus muscle
    • Iliac vessels
  • You can also lightly “jiggle” the probe as shown below to help mitigate bowel gas artifact.
Video 1: External view of the RLQ abdomen with the application of graded compression, such that bowel gas is moved out of the way to obtain a view of the desired anatomical structures
Video 2: POCUS clip of the RLQ abdomen demonstrating the application of graded compression and “jiggling” the probe

1. Start in the RLQ Abdomen

appendicitis pediatric abdomen

Figure 2: Starting in the RLQ abdomen and inferior to the iliac crest, visualize the iliacus muscle and pelvis with no bowel in view. The first bowel you visualize should be the cecum as you scan in a cephalad direction.

Video 3: POCUS clip of the RLQ abdomen showing the cecum coming into view

2. Move the probe more cephalad

Figure 3: Moving the probe in a progressively more cephalad direction, attempt to visualize the iliopsoas, abdominis rectus muscles, and iliac vessels. These anatomic landmarks to help identify the appendix (marked as *) with the CURVILINEAR probe. The appendix may appear in the triangle made by these structures as a blind-ended pouch that does not have peristalsis.[Image courtesy of Dr. Sally Graglia]

Figure 4: Anatomic landmarks to help identify the appendix with the LINEAR probe [image courtesy of Dr. Sally Graglia]

3. Identify the tubular appendix structure

Figure 5: Visualize the appendix in the longitudinal view. In this plane, visualize the end of the pouch to confirm it is a blind-ending tubular structure with no peristalsis that initiates at the cecum. [Image courtesy of Dr. Margaret Martore-Lin]

Figure 6: Visualize the appendix in the transverse view. In this plane, measure the diameter of the appendix from the outer wall to outer wall. An abnormal appendix is >6 mm and non-compressible. [Image courtesy of Dr. Margaret Martore-Lin]

A technique described in Sivitz et al. [1] involves placing the ultrasound probe in a transverse position and starting at the level of the umbilicus. Using compression, move the probe along POCUS-identified anatomical landmarks.

  1. Move laterally to identify the lateral border of the ascending colon.
  2. Move down the lateral border to the end of the cecum.
  3. Move medially across the psoas and iliac vessels.
  4. Move down the border of the cecum.
  5. Move up the border of the cecum.
  6. Rotate the probe into a sagittal position and identify the end of the cecum in the long axis and move medially across the psoas.

Figure 7: The Sivitz et al technique for identifying the appendix on POCUS

Sometimes there is a suboptimal view of the anatomy landmarks on POCUS. The following are troubleshooting tips that may be useful:

  1. Perform graded compression to displace bowel gas that may be obscuring your view.
  2. Apply posterior manual compression to the right lower back in an anteromedial direction of the ultrasound probe. This is usually done with the POCUS operator’s opposite hand (Figure 7).
pediatric appendicitis POCUS posterior compression

Figure 8: Posterior manual compression technique to assist with POCUS visualization of the appendix

  1. Position the patient in the left lateral decubitus position to help visualization of a retrocecal appendix.
  2. Administer analgesia before starting and distraction (videos, smartphone) during the exam to reduce patient movement.
  3. Position the patient with knees flexed, which can relax the abdominal wall musculature.
  4. Use a high-frequency linear probe to improve the resolution of regional structures and anatomy (although a curvilinear probe should be used if increased depth is required for a larger body habitus).

pediatric normal appendix POCUS

Figure 9: Normal appearing appendix on POCUS [Image courtesy of Dr. Will Shyy]

The appendix is a tubular, blind ending structure, which initiates from the cecum and has no peristalsis. A normal appendix is less than 6 mm, is compressible, and has little to no blood flow in the wall of the appendix.

Ultrasonography Signs of Acute Appendicitis

  1. Enlarged appendix >6 mm (Figure 10)
  2. Noncompressible (although can be compressible if perforated appendix)
pediatric appendicitis POCUS

Figure 10: Enlarged appendix measuring 1.36 cm (>6 mm is abnormal) with hyperechoic fat concerning for inflammation [Image courtesy of Dr. Will Shyy]

Secondary Ultrasonographic Signs of Appendicitis

  1. Peri-appendiceal free fluid
  2. Hyperechoic mesenteric fat
  3. Appendicolith
  4. Increased blood flow (“ring of fire”) surrounding the appendix on Doppler color mode
  5. Complex right lower quadrant mass, suggestive of ruptured appendix
Secondary Sign of AppendicitisUltrasound View
Peri-appendiceal free fluid secondary to inflammatory edema or perforation. You may also see an abscess that appears as a complex mass and is a sign of a ruptured appendicitis.
pediatric appendicitis POCUS

Figure 11. Appendix with peri-appendiceal fluid collection [image by Dr. Will Shyy]

Hyperechoic mesenteric fat as a sign of inflammation visible (also see figure 10)
pediatric appendicitis POCUS

Figure 12: Appendicolith (A) within the lumen of the appendix in addition to hyperechoic fat (arrows) concerning for inflammation [image courtesy of Dr. Will Shyy]

pediatric appendicitis POCUS

Figure 13. Appendicitis with hyperechoic fat suggestive of inflammation

Video 4: POCUS clip of a pediatric patient with appendicitis. Notice the hyperechoic fat surrounding the appendix, visible in transverse as a tubular structure at the bottom of the screen. [Video courtesy of Dr. Ashkon Shaahinfar]
Appendicolith: A hyperechoic structure within the appendiceal lumen has a dark, clean acoustic shadow, similar to the appearance of a gallstone.Figure 12 above
“Ring of Fire”, or increased blood flow surrounding the appendix: Using the color Doppler mode on the ultrasound, the appendix in transverse view will appear hyperemic, suggestive of appendiceal inflammation.
pediatric appendicitis POCUS ring of fire

Figure 14. “Ring of fire” appendiceal hyperemia using the color Doppler mode on ultrasound [image by Dr. Will Shyy]

pediatric appendicitis POCUS

Figure 15. Cross-sectional image of appendicitis with hyperemia

Complex RLQ mass: A ruptured appendicitis may appear as a complex right lower quadrant mass, where the appendix itself may be difficult to visualize. It can be difficult to distinguish this from other pathologies, such as intussusception or ruptured Meckel’s diverticulitis.

Video 5: POCUS clip of ruptured appendicitis, appearing as a complex right lower quadrant mass [Video courtesy of Dr. Ashkon Shaahinfar]​
pediatric appendicitis POCUS

Figure 16. Close-up POCUS view of the appendix from video 5 [image courtesy of Dr. Ashkon Shaahinfar]

Benefits of Appendix POCUS

An appendix POCUS benefits children with suspected appendicitis, as demonstrated in the literature:

  1. Decrease in CT scan utilization [2-4]
  2. Decrease in lengths of Emergency Department stay [3, 4]
    • Tsung et al, Critical Ultrasound J, 2014 [4]: There was a shorter ED length of stay (LOS) with mean LOS reported for the following modalities:
      • POCUS: 154 minutes
      • Radiology US: 288 minutes
      • CT scan: 487 minutes

Equivocal Findings on POCUS

  • Oftentimes an appendix cannot be visualized on both POCUS and radiology-performed ultrasound, especially in patients with higher BMI [5].
  • In situations with an experienced sonographer, where the appendix is not visualized and there are no secondary signs on radiology-performed ultrasound, patients are at low risk for appendicitis with a negative predictive value in the 80’s% [6, 7].
  • Serial ultrasound has been recommended in equivocal ultrasound cases as ultrasound’s sensitivity increases with length of pain [8].
  • For POCUS for appendicitis, non-visualized appendix studies continue to represent a diagnostic dilemma [1, 9]. For more on this topic, read a deeper-dive on this topic in a PEM Pearls post.

The studies below examine the sensitivity and specificity of appendix POCUS for identification of appendicitis in patients of any age with the exception of Sivitz et al., which specifically studied pediatric patients only. (Table 1).

StudyNPatient AgeSensitivitySpecificityComments
Sivitz et al., 2014 [1]264Pediatric
85%
(95% CI: 75-95%)
93%
(95% CI: 85-100%)
In this study, pediatric emergency medicine ultrasonographers were able to visualize the appendix in 71% of patients. Gold standard was either pathologic review, telephone follow-up to 6 months, or electronic medical records review up to 1 year, if unable to reach the patient.
Fields et al., 2017 [9]6,636Pediatric89%

(95% CI: 47–99%)

97%

(95% CI: 84–99%)

These test characteristics were derived from a pediatric-only sub-analysis of a larger systematic review and meta‐analysis study across all ages to identify the test characteristics of the appendix POCUS, performed by emergency physicians. The overall test characteristics across all ages was 91%
(95% CI: 83–96%) sensitivity and 97% (95% CI: 91–99%) specificity.
Chen et al., 2000 [10]317Any age85%98%After a 5-day intensive training course in abdominal ultrasound, emergency physician-performed POCUS was compared to surgeon’s clinical impression in diagnosing acute appendicitis, as confirmed by pathological reports. Ultrasonography performed better than surgeon clinical impression and resulted in a high sensitivity and specificity.
Fox et al., 2008 [11]132Any age65%

(95% CI: 52-76%)

90%

(95% CI: 81-95)

Emergency physicians performed a 5-minute appendix POCUS for patients with a clinical suspicion for acute appendicitis. The gold standard confirmation was either pathology specimens from appendectomy surgery or telephone follow-up.
Table 1. Published studies evaluating the sensitivity and specificity of appendix POCUS

Case Resolution

The patient has a leukocytosis with a WBC 13.3 x 109/L and an absolute neutrophils count (ANC) 10.3 x 109/L but otherwise unremarkable labs. His final Pediatric Appendicitis Score (PAS) is 8. You decide to incorporate appendix POCUS to your evaluation. You place a linear, high-frequency transducer on the patient and visualize his appendix. You observe the following:

Video 6. An appendix POCUS, demonstrating appendicitis.

Figure 17: Enlarged appendix measuring 1.36 cm in diameter (>6 mm is abnormal)

Normal anatomy for comparison:

Video 7: Appendix POCUS clip showing normal anatomy including the psoas muscle, vasculature, and a small, compressible appendix.

ED Course

The patient receives IV morphine and is made NPO. The general surgeon on call is consulted and agrees with the plan for an appendectomy.

Learn More…

References

  1. Sivitz AB, Cohen SG, Tejani C. Evaluation of acute appendicitis by pediatric emergency physician sonography. Ann Emerg Med. 2014;64(4):358-364.e4. doi:10.1016/j.annemergmed.2014.03.028. PMID: 24882665
  2. Doniger SJ, Kornblith A. Point-of-Care Ultrasound Integrated Into a Staged Diagnostic Algorithm for Pediatric Appendicitis. Pediatr Emerg Care. 2018;34(2):109-115. doi:10.1097/PEC.0000000000000773. PMID: 27299296
  3. Elikashvili I, Tay ET, Tsung JW. The effect of point-of-care ultrasonography on emergency department length of stay and computed tomography utilization in children with suspected appendicitis. Acad Emerg Med. 2014;21(2):163-170. doi:10.1111/acem.12319. PMID: 24673672
  4. Tsung JW, Tay ET, Elikashvili I.  The effect of point-of-care ultrasonography on emergency department length of stay and CT utilization in children with suspected appendicitis. rit Ultrasound J 6, A32 (2014). https://doi.org/10.1186/2036-7902-6-S1-A32
  5. Abo A, Shannon M, Taylor G, Bachur R. The influence of body mass index on the accuracy of ultrasound and computed tomography in diagnosing appendicitis in children. Pediatr Emerg Care. 2011;27(8):731-736. doi:10.1097/PEC.0b013e318226c8b0. PMID: 21811194
  6. Cohen B, Bowling J, Midulla P, et al. The non-diagnostic ultrasound in appendicitis: is a non-visualized appendix the same as a negative study?. J Pediatr Surg. 2015;50(6):923-927. doi:10.1016/j.jpedsurg.2015.03.012. PMID: 25841283
  7. Ly DL, Khalili K, Gray S, Atri M, Hanbidge A, Thipphavong S. When the Appendix Is Not Seen on Ultrasound for Right Lower Quadrant Pain: Does the Interpretation of Emergency Department Physicians Correlate With Diagnostic Performance?. Ultrasound Q. 2016;32(3):290-295. doi:10.1097/RUQ.0000000000000214. PMID: 27082937
  8. Bachur RG, Dayan PS, Bajaj L, et al. The effect of abdominal pain duration on the accuracy of diagnostic imaging for pediatric appendicitis. Ann Emerg Med. 2012;60(5):582-590.e3. doi:10.1016/j.annemergmed.2012.05.034. PMID: 22841176
  9. Matthew Fields J, Davis J, Alsup C, et al. Accuracy of Point-of-care Ultrasonography for Diagnosing Acute Appendicitis: A Systematic Review and Meta-analysis. Acad Emerg Med. 2017;24(9):1124-1136. doi:10.1111/acem.13212. PMID: 2846445
  10. Chen SC, Wang HP, Hsu HY, Huang PM, Lin FY. Accuracy of ED sonography in the diagnosis of acute appendicitis. Am J Emerg Med. 2000;18(4):449-452. doi:10.1053/ajem.2000.7343. PMID: 10919537
  11. Fox JC, Solley M, Anderson CL, Zlidenny A, Lahham S, Maasumi K. Prospective evaluation of emergency physician performed bedside ultrasound to detect acute appendicitis. Eur J Emerg Med. 2008;15(2):80-85. doi:10.1097/MEJ.0b013e328270361a. PMID: 18446069

Additional Reading

  1. Benabbas R, Hanna M, Shah J, Sinert R. Diagnostic Accuracy of History, Physical Examination, Laboratory Tests, and Point-of-care Ultrasound for Pediatric Acute Appendicitis in the Emergency Department: A Systematic Review and Meta-analysis. Acad Emerg Med. 2017;24(5):523-551. doi:10.1111/acem.13181. PMID: 28214369
  2. Estey A, Poonai N, Lim R. Appendix not seen: the predictive value of secondary inflammatory sonographic signs. Pediatr Emerg Care. 2013;29(4):435-439. doi:10.1097/PEC.0b013e318289e8d5. PMID: 23528502Lin-Martore M, Kornblith AE. Diagnostic Applications of Point-of-Care Ultrasound in Pediatric Emergency Medicine. Emerg Med Clin North Am. 2021 Aug;39(3):509-527. doi: 10.1016/j.emc.2021.04.005. PMID: 34215400
  3. Vasavada P. Ultrasound evaluation of acute abdominal emergencies in infants and children. Radiol Clin North Am. 2004;42(2):445-456. doi:10.1016/j.rcl.2004.01.003. PMID: 15136027
By |2024-02-29T02:28:42-08:00May 31, 2022|Pediatrics, PEM POCUS, Ultrasound|
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