FacebookRssTwitterInstagramSoundCloud
Generic filters
Exact matches only

SAEM Clinical Images Series: A Dangerous Cause of Abdominal Pain

liver abscess

A 65-year-old male presented with chest and abdominal pain for three weeks. He endorsed a poor appetite and a weight loss of 16 kilograms in the last month. He denied fever, vomiting, diarrhea, and tarry stools and described having his usual bowel movements.

 

Vitals: BP 172/71; HR 127; T 35.9°C; O2 Sat 100%

General: In acute distress

Cardiovascular: Regular rate and rhythm; no murmur; bilateral upper extremity and lower extremity pulses palpable

Gastrointestinal: Soft; generalized tenderness, no abdominal masses, palpable subcutaneous emphysema

Complete blood count (CBC): WBC 31 x 10^3/mcl; Hgb 15 g/dl; Hct 49.1%; Plt 477 x 10^3/mcl

Basic metabolic panel (BMP): Na 130 mmol/L; K 5.6 mmol/L; Glucose 538 mg/dL

CRP: 42.6 mg/dL

Ketone body: 5.9 mmol/L

Venous blood gas (VBG): pH 6.967; pCO2 27.9 mmHg; pO2 45.8 mmHg; BE -24.7 mmol/L

Rupture of gas-forming pyogenic liver abscess complicated by necrotizing fasciitis. The most common pathogen is Klebsiella pneumoniae, and diabetes mellitus is the most common risk factor.

Treatment includes drainage, systemic antibiotic therapy, and emergent surgical intervention.

Take-Home Points

  • Gas-forming pyogenic liver abscess is a rare but life-threatening disease. Consider it especially in the patient with abdominal pain with diabetes mellitus.
  • Treatment includes not only drainage and systemic antibiotic therapy, but also emergent surgical intervention if complicated by necrotizing fasciitis.

  • Chen CE, Shih YC. Monomicrobial Klebsiella pneumoniae Necrotizing Fasciitis With Liver Abscess: A Case Report and Literature Review. Ann Plast Surg. 2017 Mar;78(3 Suppl 2):S28-S31. doi: 10.1097/SAP.0000000000001001. PMID: 28177973.
  • Cheng NC, Yu YC, Tai HC, Hsueh PR, Chang SC, Lai SY, Yi WC, Fang CT. Recent trend of necrotizing fasciitis in Taiwan: focus on monomicrobial Klebsiella pneumoniae necrotizing fasciitis. Clin Infect Dis. 2012 Oct;55(7):930-9. doi: 10.1093/cid/cis565. Epub 2012 Jun 19. PMID: 22715175.

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 |2023-08-27T21:58:28-07:00Sep 1, 2023|Gastrointestinal, SAEM Clinical Images|
Read More

SAEM Clinical Images Series: There’s a Stone Under My Tongue

stone

A 44-year-old female presented to the emergency department with the complaint of a “stone under [her] tongue.” She reported that the “stone” had been present and painless for two years. The day prior, she began experiencing pain at this site while brushing her teeth. She squeezed the area in an attempt to expel it, but this action only increased her pain.

 

Vitals: BP 156/92; Pulse 80; Temp 98.4°F; Resp 14; SpO2 100%

General: Sitting on chair, no acute distress

HEENT: Localized swelling to the inferior lingual frenulum at Wharton’s duct with associated erythema. Partially visualized white calculus, palpable through the mucosal membrane.

None

Sialolith in Wharton’s Duct. There was visual and tactile evidence of a calculus under the patient’s tongue. It had slowly grown and was associated with increased pain and swelling while brushing her teeth.

The majority of sialoliths can be managed conservatively with hydration, moist heat application, massaging of the gland, milking the duct, and advising the patient to suck on tart candies to promote salivation. Larger, more superficial sialoliths may benefit from excision in the emergency department. In the case above, local anesthetic was injected, and manual expulsion was attempted but was unsuccessful. The emergency physician made a single 1 cm incision over the calculus and a 0.5 cm x 0.75 cm sialolith was removed with minimal bleeding. The patient was discharged on a course of amoxicillin-clavulanic acid.

Take-Home Points

  • Dehydration, trauma, anticholinergics, and diuretics predispose to the formation of sialoliths, with 80-90% arising from the submandibular glands. As with our patient, the most common presentation is a single calculus within Wharton’s duct causing pain and swelling during periods of increased salivation.
  • Conservative treatment is the mainstay of sialolith management. Larger, more superficial sialoliths may require excision. Imaging and specialist referral should be considered in cases concerning for tumor, abscess, or treatment failure.

  • Huoh KC, Eisele DW. Etiologic factors in sialolithiasis. Otolaryngol Head Neck Surg. 2011 Dec;145(6):935-9. doi: 10.1177/0194599811415489. Epub 2011 Jul 13. PMID: 21753035.

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 |2023-08-27T21:38:49-07:00Aug 28, 2023|HEENT, SAEM Clinical Images|
Read More

SAEM Clinical Images Series: A Painful Swollen Digit

finger

A 50-year-old male with a history of polysubstance use disorder and poorly-controlled type 2 diabetes mellitus presents with left hand pain. One week ago, the patient sustained a macerating injury of the left distal middle digit. Since that time he has experienced worsening pain throughout the digit, now associated with diffuse swelling and discoloration. The patient also reports reduction in range of motion.

Vitals: Temp 97.6°F (36.4°C); BP 134/89; HR 87; Resp 16

General: Uncomfortable appearing male.

Musculoskeletal: Left hand third digit with fusiform edema, diffuse erythema, and warmth. Held in passive flexion at rest. Skin breakdown noted at distal fingertip with scant serous drainage. Tender to palpation, most markedly over the volar surface of the PIP joint. Patient reports severe pain with passive extension at the MCP, PIP, and DIP joints.

Glucose: 296

White Blood Cell (WBC) Count: 8,000/μl

ESR: 54 mm/hr

Infectious flexor tenosynovitis is an infection of the flexor tendon and synovial sheath with a significant risk of complications (e.g., tendon rupture, loss of function, amputation) if not promptly treated. Patients classically present 2-4 days after penetrating trauma to the hand (e.g., bite/scratch, puncture wound, laceration, injection).

This diagnosis is suggested clinically by four cardinal findings, the Kanavel signs:

1) diffuse “fusiform” swelling of the digit (most common)

2) digit held in passive flexion

3) tenderness to percussion over the flexor sheath

4) pain with passive extension

Although fundamentally a clinical diagnosis, the initial evaluation for infectious flexor tenosynovitis should include laboratory studies including complete blood count (CBC) and inflammatory markers (ESR/CRP). Radiographs may be performed to evaluate for occult traumatic injury or foreign body. Treatment includes emergent consultation of orthopedics or hand surgery, initiation of intravenous (IV) antibiotics, and hospital admission. Antibiotics should target gram-positive organisms (Staphylococcus, including MRSA, and Streptococcus). In immunocompromised patients, additional coverage against gram-negative organisms and anaerobes may be needed. Risk factors for poor outcomes include immunocompromise (HIV, diabetes, immunosuppression), intravenous drug use, peripheral vascular disease, and polymicrobial infection.

Take-Home Points

  • Infectious flexor tenosynovitis is a surgical emergency that is diagnosed clinically by the presence of one or more of the four Kanavel signs on physical exam.
  • History of trauma or penetrating injury and immunocompromised status should raise suspicion for infectious flexor tenosynovitis; common pathogens include Staphylococcus and Streptococcus species.
  • Treatment includes emergent consultation with orthopedics or hand surgery as well as early initiation of IV antibiotics.

  • Ritter K, Fitch R. Tenosynovitis. In: Knoop KJ, Stack LB, Storrow AB, Thurman R. eds. The Atlas of Emergency Medicine, 5e. McGraw Hill; 2021. Accessed November 30, 2022. https://accessmedicine-mhmedical-com.ezproxy.bu.edu/content.aspx?bookid=2969&sectionid=250459435.
  • Hyatt MT, Bagg MR. Flexor Tenosynovitis. OrthopClin N Am 2017;48:217-27.
  • Pang HN, Teoh LC, Yam AKT, Lee JYL, Puhaindran ME, Tan ABH. Factors affecting the prognosis of pyogenic flexor tenosynovitis. Journal of Bone and Joint Surgery. 2007;89(8):1742-1748.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-08-14T14:28:46-07:00Aug 21, 2023|Infectious Disease, Orthopedic, SAEM Clinical Images|
Read More

SAEM Clinical Images Series: A Man with Blurry Vision

cranial nerve

A middle-aged man with a past medical history of hypertension and tobacco use disorder presented to the Emergency Department after evaluation by an ophthalmologist.  He complained of ten days of a right-sided headache and three days of diplopia. He denied eye pain, pain with eye movements, photophobia, and vision loss.

Vitals: Temp 98.4 °F (36.9 °C); BP 122/72; Pulse 90; Resp 16; SpO2 100%

Neuro: Ptosis, “down and out” deviation and pupil dilation of the right eye were noted. Extraocular movements were intact and pupils were reactive to light bilaterally. No other neurologic deficits were observed.

Non-contributory

This patient has a partial cranial nerve (CN) III (oculomotor nerve) palsy. CN III is composed of: (a) internal somatic motor fibers that innervate the levator palpebrae superioris (which elevates the upper eyelid) and the medial recti, superior recti, inferior recti, and inferior oblique extraocular muscles, and (b) external parasympathetic fibers innervating the ciliary muscles (involved in accommodation) and sphincter pupillae (involved in pupillary constriction). The presentation of complete isolated CN III palsy generally involves ipsilateral ptosis (due to levator palpebrae paralysis) and “down and out” ocular deviation (due to preservation of superior oblique and lateral rectus function).

The most common etiology of CN III palsy is ischemia of the nerve fibers secondary to diabetes mellitus or hypertension, which preferentially affects the internal somatic fibers that surround the blood supply. This etiology classically results in a pupil-sparing palsy due to preserved function of the external parasympathetic fibers. However, the most feared etiology is an intracranial aneurysm, most commonly a posterior communicating artery aneurysm. This source of external compression classically affects both the internal somatic motor fibers and external parasympathetic fibers, resulting in asymmetric pupil dilation.

Take-Home Points

  • CN III palsy etiologies include ischemia secondary to diabetes mellitus or hypertension, and structural causes, most commonly a posterior communicating artery aneurysm.
  • On exam, complete CN III palsies will present with ipsilateral ptosis, “down and out” ocular deviation, and pupillary dilation. Partial CN III palsies may have a more subtle presentation.
  • New-onset CN III palsy should be evaluated with a CTA to rule out an aneurysm.

  • Biousse V, Newman NJ. Third nerve palsies. Semin Neurol. 2000;20(1):55-74. doi: 10.1055/s-2000-6833. PMID: 10874777. 2. Singh A, Bahuguna C, Nagpal R, Kumar B. Surgical management of third nerve palsy. Oman J Ophthalmol. 2016 May-Aug;9(2):80-6. doi: 10.4103/0974-620X.184509. PMID: 27433033; PMCID: PMC4932800.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-08-14T14:10:25-07:00Aug 18, 2023|Neurology, SAEM Clinical Images|
Read More

SAEM Clinical Images Series: The Color Purple

purple urine

A 64-year-old female with a history of quadriplegia and bladder rupture secondary to a motor vehicle accident two years ago, complicated by chronic indwelling suprapubic foley, presents from her skilled nursing facility with fever, oliguria, tachycardia, low blood pressure, and a change in the color of her urine.

Vitals: T 100.4°F; HR 126; BP 105/74; RR 24

General: Pleasant but mildly confused morbidly obese female smelling strongly of urine

Genitourinary: Poorly maintained indwelling suprapubic catheter with purulence noted around the ostomy and purple urine in her foley tubing and bag

Urinalysis (UA): 168 WBC, >182 RBC, Large leukocyte esterase, Positive nitrite

This is a case of Purple Urine Bag syndrome (PUBS), an uncommon subset of CAUTI that generally occurs in female patients with constipation and an indwelling foley. Although not fully understood, it is thought that the long stool transit time of constipation allows GI flora to break tryptophan down into indoles which travel to the liver via the portal system where they become indoxyl sulfate, which is excreted into the urine. Bacterial enzymes there catalyze this to indoxyl which oxidizes in alkaline urine to both indigo (blue) and indirubin (red), the combination of which, plus interaction with the plastic catheter tubing, causes the vivid purple discoloration. Risk factors include women, chronically catheterized, elderly, recurrent UTI, institutionalization, and chronic constipation.

Causative organisms are primarily gram-negative and include Proteus mirabilis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Morganella morganii, and Enterococcus species.

Take-Home Points

  • PUBS is a rare subset of CAUTI primarily caused by gram-negative bacteria.
  • It is predominantly found in women, chronically catheterized, institutionalized, and constipated patients.
  • Treatment is appropriate antibiotics and improved foley hygiene, foley exchange as well as improved bowel regimen to increase stool transit time.

  • Meekins Pauline, Ramsay Amy, Ramsay Michael. Purple Urine Bag Syndrome. West J Emerg Med. 2012 Dec;13(6):499-500. 2. Scleszka Laura, Swan Tricia. October 9, 2020. Can Urine Color Guide Management? [online] EMRA. Available at: https://www.emra.org/emresident/article/purple-urine-bag-syndrome/ [Accessed 19 Dec. 2022]

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-08-14T09:14:36-07:00Aug 14, 2023|Infectious Disease, SAEM Clinical Images|
Read More

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|
Read More
Go to Top