PEM POCUS Series: Hip Effusion

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


PATIENT CASE: Child with a Limp

Sarah is a 4-year-old girl who comes into the emergency department complaining of a limp for the last day. She had an upper respiratory infection which started a week ago for which she had been taking acetaminophen and ibuprofen with her last dose of either being 2 days ago. Those symptoms have improved. Yesterday, she started complaining of diffuse right leg pain primarily at her hip, thigh, and knee. Today, her parents noted she was walking with a limp.

On arrival, her vital signs are:

Vital SignFinding
Temperature100.1F
Heart rate100 bpm
Blood pressure97/50
Respiratory rate19
Oxygen saturation (room air)100%

She is well appearing and walks with an antalgic gait favoring the left leg. She has a normal HEENT, neck, cardiac, respiratory, abdominal, and back examination. She points to her right anterior thigh when you ask her where her pain is. She has limited range of motion with internal and external rotation of her right hip and complains of pain. She cries when you palpate any part of her leg, but is able to range her knee, ankle, and foot fully. She has 2+ dorsalis pedis and posterior tibialis pulses and intact sensation to light touch throughout. 

Given her pain with range of motion at her hip, you order a hip radiograph, but while waiting for it, decide to perform a hip point of care ultrasound (POCUS) examination.

PEDIATRIC HIP EFFUSION: Ultrasound Technique

It can be difficult for children to locate the exact area of pain and often hip pain can present with referred knee and thigh pain. A thorough physical examination along with hip POCUS can help localize the area of discomfort. When we use POCUS to evaluate the hip, we are primarily looking for a joint effusion in the synovial space. This is best visualized anterior to the femoral neck.  

hip anatomy hip effusion
Figure 2. Hip anatomy with target landmark being the femoral neck (red arrow) 

Technique

  1. The patient should be positioned supine.
    • Depending on the age of the child, the child can be positioned supine in the guardian’s lap while undergoing the examination. 
    • Offering the child a toy, book, or phone/tablet for distraction during the examination can also help ease anxiety.
  2. Use a linear high frequency transducer with a wide footprint.
  3. Place the transducer along the anterior hip.
    • Use the greater trochanter as a lateral landmark and place the probe on top of the femoral head and neck (Figure 3)
  4. Aim the probe marker towards the patient’s umbilicus.
hip effusion ultrasound
Figure 3. Linear transducer at the hip with probe marker (red dot) aimed towards the patient’s umbilicus
  1. Identify the anatomical landmarks on ultrasound (figure 4) 
    • Hip muscles: Sartorius, quadriceps, and iliopsoas
    • Bones: Femoral head, femoral neck
  2. The area of interest in looking for a hip effusion is the synovial space anterior to the femoral neck and NOT anterior to the femoral head. This area is also referred to as the anterior synovial recess.
Figure 4. Ultrasound image showing the normal landmarks for a pediatric hip without an effusion and the location of the femoral head (X) and synovial space (circle) with the linear transducer positioned overlying and longitudinal to the femoral neck
  • Tips:
    • It is often helpful to ultrasound the unaffected side as a comparison.
    • Be aware of the patient’s comfort throughout the examination.

ABNORMAL ULTRASOUND FINDINGS

A hip effusion will appear anechoic (black) in the synovial space anterior to the femoral neck (anterior synovial recess). Measure the distance between the anterior surface of the femoral neck and the posterior surface of the iliopsoas muscle. Examples are illustrated in figures 5 and 6.

hip effusion PEM POCUS ultrasound

There have been different methods used to assess if an effusion is present including:​1,2​

  • Measured effusion is >0.5 cm 
  • Measured effusion with >0.2 cm difference compared to the contralateral hip
  • Gestalt view with the anterior synovial recess areas appearing asymmetric compared to the other hip

Limitations of the Hip POCUS

Note that hip POCUS does not tell you the cause of an effusion but rather only whether an effusion is present or not. Effusions can result from infectious, inflammatory, and traumatic etiologies, and thus it is important to take into account the context of the patient’s presentation. 

References

  1. Vieira R, Levy J. Bedside ultrasonography to identify hip effusions in pediatric patients. Ann Emerg Med. 2010;55(3):284-289. PMID 19695738
  2. Cruz C, Vieira R, Mannix R, Monuteaux M, Levy J. Point-of-care hip ultrasound in a pediatric emergency department. Am J Emerg Med. 2018;36(7):1174-7. PMID 29223689 

FACTS and LITERATURE REVIEW

There have been multiple case reports of hip POCUS identifying hip effusions in children with fractures, septic joints, and in the work up of children with limps.​1–3​ There are limited studies examining the accuracy of hip POCUS compared to radiology-performed ultrasound in children (table 1).

StudyNSensitivitySpecificityComments
Vieira et al., Ann Emerg Med, 2010​4​2885%93%If the pediatric emergency physician had a high confidence in ultrasound accuracy, the sensitivity increased to 90% and specificity to 100%
Cruz et al., Am J Emerg Med, 2018​5​51685%98%For each additional hip POCUS performed, the odds of an accurate scan increased by 2.4%. 
Table 1. Published studies comparing pediatric hip POCUS to radiology-performed ultrasound

 

References [click to expand] +

  1. Deanehan J, Gallagher R, Vieira R, Levy J. Bedside hip ultrasonography in the pediatric emergency department: a tool to guide management in patients presenting with limp. Pediatr Emerg Care. 2014;30(4):285-287. PMID 24694889
  2. Garrison J, Nguyen M, Marin J. Emergency Department Point-of-Care Hip Ultrasound and Its Role in the Diagnosis of Septic Hip Arthritis: A Case Report. Pediatr Emerg Care. 2016;32(8):555-557. PMID 27490732
  3. Tsung J, Blaivas M. Emergency department diagnosis of pediatric hip effusion and guided arthrocentesis using point-of-care ultrasound. J Emerg Med. 2008;35(4):393-399. PMID 18403170 
  4. Vieira R, Levy J. Bedside ultrasonography to identify hip effusions in pediatric patients. Ann Emerg Med. 2010;55(3):284-289. PMID 19695738
  5. Cruz C, Vieira R, Mannix R, Monuteaux M, Levy J. Point-of-care hip ultrasound in a pediatric emergency department. Am J Emerg Med. 2018;36(7):1174-1177. PMID 29223689 

CASE RESOLUTION

The patient’s hip plain film radiographs are unremarkable. You decide to incorporate hip POCUS to your evaluation. You place a linear, high-frequency transducer and visualize the patient’s bilateral hips. You observe the following:

Right Hip (Affected Side) POCUS Video and Key View

Though the child complained of hip, knee, and thigh pain, your POCUS evaluation identifies a right hip effusion which helps you narrow the location of her pain.

Video 1. A hip POCUS of the case patient’s right hip (affected side)

 

PEM POCUS hip effusion
Figure 7. Right (affected side) hip POCUS with a hip effusion measuring 0.77 cm

Left Hip (Normal Side) POCUS Video and Key View

Video 2. A hip POCUS of the case patient’s left hip (unaffected side) for comparison

 

PEM POCUS hip no effusion normal
Figure 8. Left (unaffected side) hip POCUS with no effusion

ED Course

The patient’s labs result, and she has reassuring labs, which include a serum WBC 8.3 x109/L and ESR 34 mm/hr. The patient receives ibuprofen during her visit and within 1 hour is able to walk without a significant limp and states she feels better. The patient’s family notes they have spent the last few weeks of summer in a Lyme-endemic region, and so you send off Lyme titers.

Given the resolution of limp, lack of fever, and reassuring lab values, you do not believe the patient has a septic joint. Her effusion is more likely the result of a transient tenosynovitis. You recommend close pediatrician follow-up.

Pediatrician Clinic Follow-Up

At her pediatrician clinic visit 1 week later, her Lyme titers return negative, and the patient continues to be limp-free.  

 

The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

Read other PEM POCUS tutorials. Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series.

By |2021-07-21T18:55:01-07:00May 17, 2021|Orthopedic, PEM POCUS, Ultrasound|

PEM POCUS Series: Intussusception

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

 


PATIENT CASE

Johnny is a 2-year-old boy who comes into the emergency department for abdominal pain for the last day. His parents are concerned that he has been having intermittent abdominal pain and has seemed very tired all day. Parents deny bloody stool.

On arrival, his vital signs are:

Vital SignFinding
Temperature36.9C
Heart rate110 bpm
Blood pressure97/50
Respiratory rate22
Oxygen saturation (room air)99%

He is tired appearing, and his abdominal exam is soft but diffusely tender. Given his intermittent abdominal pain, you decide to perform an intussusception point of care ultrasound (POCUS) exam.

ULTRASOUND TECHNIQUE

Intussusception is when one part of the bowel telescopes, or gets stuck, in another part of the bowel. Typically intussusception refers to ileocolic intussusception where the ileum becomes stuck in the colon. To perform the ultrasound, start in the right lower quadrant and trace the colon. See below for a step-by-step technique.

intussusception
Overview of sequential ultrasound transducer positioning on the anterior abdomen to assess for intussusception

Technique

  • The patient should be positioned supine.
  • To aid in comforting the child, the child can be positioned supine in the parent’s lap while undergoing the scan. Having the parent or another provider offer a toy, book, or phone/tablet to distract the child during the scan can also help ease anxiety.
  • Begin in the right lower quadrant (RLQ), using a high frequency linear probe with the probe marker to patient’s right.
  • First, identify the anatomical landmarks in the RLQ (see ultrasound images below):
    • Psoas muscle (green) laterally
    • Right iliac vessels (blue)
    • Abdominal muscles (red)
    • Bladder (yellow) medially

Ultrasound image: Anterior Abdomen (RLQ) View

intussusception RLQ ultrasound

Ultrasound Image: Anterior Abdomen RLQ (More Medial) View

PEM POCUS intussusception RLQ More Medial
  • Perform graded compression, with slow steady pressure to displace bowel gas
  • Follow the colon from the RLQ to right upper quadrant (RUQ) until the liver (purple) and gallbladder are identified

Ultrasound Image: Anterior Abdomen (RUQ) View

PEM POCUS intussusception RUQ
  • Rotate the probe marker to patient’s head and scan the entire length of the transverse colon.
  • Rotate the probe marker back to patient’s right and scan the entire length of the descending colon, making sure to scan all four quadrants.
  • Save representative video clips and still images of each quadrant.
  • If an intussusception is found, measure its diameter in transverse view and note in which quadrant(s) it is found.
  • At the end of scan, if you have found an intussusception, re-image the abdomen to make sure it was not transient.
  • The provider should maintain awareness of the patient’s comfort throughout the scan.

INTUSSUSCEPTION CLASSIC FINDINGS

Normal (no intussusception)

Normal: There is no target or sandwich sign, but rather just folded normal bowel. (To replay, press circular arrow in bottom left corner)

Abnormal findings

  • Look for findings of a sandwich sign (or pseudo-kidney sign) in the longitudinal view and target sign (or donut sign) in the transverse view.
  • If visualized, measure the diameter of the intussusception in short axis (transverse) and note which in which quadrant(s) it is located.

Sandwich

Anterior abdomen ultrasound: Intussusception – Presence of a sandwich sign (long axis view) and target sign (short axis view)

Target Sign

Intussusception diameter ultrasound
Measurement: The diameter of an intussusception (i.e., target sign) in transverse view involves measuring the distance from outer wall to outer wall.

Additional Anterior Abdominal Ultrasound Videos

Pro Tip
It can be difficult to distinguish intussusception of the small bowel-small bowel (i.e., when the ileum or part of the small bowel telescopes into itself) versus ileocolic (i.e., when the ileum becomes telescopes into the colon). The former often does not require a procedure for reduction, while the latter typically does. If the target sign diameter is <2 cm and transient, a small bowel-small bowel intussusception should be suspected. The length of the intussusception, or how many quadrants are involved, can also be measured for an idea of how much bowel is involved.

Small bowel-small bowel intussusception

Small bowel-small bowel intussusception – Note the small size of the target lesion. Because the ultrasound video scans to a depth of 3.3 cm (see bottom right side of the screen), the target sign appears to be approximately only 1 cm in diameter.

 

Small bowel-small bowel intussusception – There is a target sign, but it is small (<2 cm) with a small fat (white) core.

 

Ileo-colic intussusception

Ileo-colic intussusception with classic target sign – Note the lymph nodes (black) inside the mesenteric fat (white) in the center of the target.

FACTS and LITERATURE REVIEW

Mimickers of Intussusception

There are additional pathologies that can be mistaken for intussusception such as an intussuscepted appendix, appendicitis surrounded by abscess, and Meckel’s diverticulum, which are beyond the scope of this course. Any concerning finding for intussusception should be followed by a confirmatory study by the radiology department.

Benefits of intussusception POCUS scans

Although few studies have looked at point of care ultrasonography (POCUS) for intussusception, the existing studies have shown excellent test characteristics and a decreased length of stay with using POCUS.

Two studies assessed the test characteristics of the intussusception POCUS.

PublicationStudy MethodologySensitivitySpecificity
Riera et al. (2012)​1​This journal publication was a prospective study of 82 patients who underwent POCUS by pediatric emergency medicine (PEM) providers. The gold standard was a comprehensive radiology ultrasound.85%97%
Trigylidas et al. (2017) ​2​This abstract reported a retrospective study of 105 intussusception POCUS scans by PEM providers. The gold standard was either a direct radiology over-read of the POCUS scans or a radiology department ultrasound.96.2%92.6%
Lin-Martore et al. (2020)6This systematic review and meta analysis included 1,303 patients and 6 studies.94.9%99.1%
Bergmann et al. (2021)7This prospective study of 256 children across 17 sites (35 sonologists) compared POCUS and radiology performed ultrasound using a gold standard of clinically important intussusception which was defined as an intussusception that required radiographic or surgical reduction during or within 7 days of the incident ED visit.96.6%98%

In terms of ED length of stay (LOS), Kim et al. (2017) reported that after the introduction of an intussusception POCUS scanning protocol, the LOS decreased by >200 minutes.​3​

Differentiating small bowel-small bowel from ileocolic intussusception

In general, true ileocolic intussusceptions are:

  • Found on the right side of the abdomen
  • >2 cm in diameter
  • Have mesenteric fat (which is white) and lymph nodes in the center
  • Do not self resolve

There have been studies looking at distinguishing small bowel-small bowel from ileocolic intussusception. These, however, have been radiology-based and not POCUS studies, making generalizability to the ED setting challenging. Thus, if there is a concern for an intussusception, a radiology ultrasound should be ordered.

One small study with 27 patients by Wiersma et al. (2006) found that small bowel-small bowel intussusceptions had a smaller mean diameter and length compared to ileocolic intussusceptions.​4​

Type of intussusception# of patients and scansMean diameter (range)Mean length (range)Location
Small bowel-small bowel10 patients, 11 scans1.5 cm (1.1-2.5 cm)2.5 cm (1.5-6 cm)Distributed throughout the abdomen (6 paraumbilical, 2 RUQ, 2 RLQ, 1 LLQ)
Ileocolic14 patients, 16 scans3.7 cm (3-5.5 cm)8.2 cm (5-12.5 cm)All on right side of abdomen

Lioubashevsky et al 2013​5​ had a larger sample size (174 patients) with similar findings. The authors also measured the ratio of the inner fat core to the intussusception outer wall and identified the presence or absence of lymph nodes within the lesion.

Type of Intussusception# of patientsMean diameter (range)Mean length (range)Ratio of fat core to the intussusception outer wall% of patients with lymph nodes in the lesion
Small bowel-small bowel57 patients1.4 cm 
(1.1-2.5 cm)
2.5 cm 
(1.5-6 cm)
<114%
Ileocolic143 patients2.6 cm 
(1.3-4 cm)
8.2 cm 
(5-12.5 cm)
>189.5%

References [click to expand] +

  1. Riera A, Hsiao A, Langhan M, Goodman T, Chen L. Diagnosis of intussusception by physician novice sonographers in the emergency department. Ann Emerg Med. 2012;60(3):264-268. PMID 22424652
  2. Trigylidas TE, Kelly JC, Hegenbarth MA, Kennedy C, Patel L, O’Rourke K. 395 Pediatric Emergency Medicine-Performed Point-of-Care Ultrasound (POCUS) for the Diagnosis of Intussusception. Annals of Emergency Medicine. October 2017:S155. DOI
  3. Kim J, Lee J, Kwon J, Cho H, Lee J, Ryu J. Point-of-Care Ultrasound Could Streamline the Emergency Department Workflow of Clinically Nonspecific Intussusception. Pediatr Emerg Care. September 2017. PMID 28926507
  4. Wiersma F, Allema J, Holscher H. Ileoileal intussusception in children: ultrasonographic differentiation from ileocolic intussusception. Pediatr Radiol. 2006;36(11):1177-1181. PMID 17019589
  5. Lioubashevsky N, Hiller N, Rozovsky K, Segev L, Simanovsky N. Ileocolic versus small-bowel intussusception in children: can US enable reliable differentiation? Radiology. 2013;269(1):266-271. PMID 23801771
  6. Lin-Martore M, Kornblith AE, Kohn MA, Gottlieb M. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception in Children Presenting to the Emergency Department: A Systematic Review and Meta-analysis. West J Emerg Med. 2020 Jul 2;21(4):1008-1016. doi: 10.5811/westjem.2020.4.46241. PMID: 32726276.
  7. Bergmann KR, Arroyo AC, Tessaro MO, et al; P2Network. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception: A Multicenter, Noninferiority Study of Paired Diagnostic Tests. Ann Emerg Med. 2021 Jul 2:S0196-0644(21)00340-1. doi: 10.1016/j.annemergmed.2021.04.033. Epub ahead of print. PMID: 34226072.

Case Resolution

You place a linear, high-frequency probe on the right side of the patient’s abdomen. You perform a bedside ultrasound scan, viewing transversely and longitudinally through the upper and lower abdomen. You observe the following:

What is the diagnosis?

This is an intussusception!

The intussusceptum (red) is the part of the bowel that has telescoped into the intussuscipiens (blue). When ileum becomes trapped in the colon, this can lead to ischemia and necrosis over time. This is what causes the classic “currant jelly stools”, which are bloody stools.

Tip: The classic triad of colicky abdominal pain, palpable mass and bloody stool are present in less than 50% of patients, and intussusception should be suspected for patients with vomiting, abdominal pain, and/or lethargy.​1​

Hospital course

Johnny underwent an air enema reduction in the Radiology department, which successfully reduced the ileocolic intussusception.

Reference

  1. Daneman A, Alton D. Intussusception. Issues and controversies related to diagnosis and reduction. Radiol Clin North Am. 1996;34(4):743-756. PMID 8677307.

The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series

By |2021-10-21T16:59:09-07:00May 10, 2021|Gastrointestinal, PEM POCUS, Ultrasound|

EMRad: Can’t Miss Pediatric Elbow Injuries

 

Have you ever been working a shift at 3 am and wondered, “Am I missing something? I’ll just splint and instruct the patient to follow up with their PCP in 1 week.” This can be a reasonable approach, especially if you’re concerned there could be a fracture. But we can do better. Enter the “Can’t Miss” series: a series organized by body part that will help identify common and catastrophic injuries. This list is not meant to be a comprehensive review of each body part, but rather to highlight and improve your sensitivity for these potentially catastrophic injuries. We reviewed the approach to the pediatric elbow previously. Now, the “Can’t Miss” pediatric elbow injuries. (more…)

By |2021-04-10T10:24:46-07:00Apr 5, 2021|EMRad, Orthopedic, Pediatrics, Radiology, Trauma|

EMRad: Radiologic Approach to the Pediatric Traumatic Elbow X-ray

This is EMRad, a series aimed at providing “just in time” approaches to commonly ordered radiology studies in the emergency department [1]. When applicable, it will provide pertinent measurements specific to management, and offer a framework for when to get an additional view, if appropriate. We recently covered the adult elbow, here we will cover the approach to the pediatric elbow.

Learning Objectives

  1. Interpret traumatic pediatric elbow x-rays using a standard approach
  2. Identify clinical scenarios in which an additional view might improve pathology diagnosis

Why the pediatric elbow matters and the radiology rule of 2’s

The Pediatric Elbow

  • 10% of all pediatric fractures involve the elbow [2].
  • Missed injuries can cause significant deformity, pain, or functional/neurologic complications [2].

Before we begin: Make sure to employ the rule of 2’s [3]

  • 2 views: One view is never enough.
  • 2 abnormalities: If you see one abnormality, look for another.
  • 2 joints: Image above and below (especially for forearm and leg).
  • 2 sides: If unsure regarding a potential pathologic finding, compare to another side.
  • 2 occasions: Always compare with old x-rays if available.
  • 2 visits: Bring the patient back for repeat films.

An approach to the traumatic pediatric elbow x-ray

  1. Adequacy / Alignment
  2. Effusions or Fat Pads
  3. Bones, Growth Plates, and Ossification Centers
  4. Consider an additional view

1.   Adequacy / Alignment

2.   Effusions or Fat Pads

  • An anterior fat pad can be normal, but is considered pathologic if excessively prominent (usually around ≥20 degrees from the humerus, or “sail sign”).
  • A clearly visualized posterior fat pad is always pathologic.
  • If either the sail sign or posterior fat pad is present, consider a supracondylar fracture or intra-articular fracture (e.g. lateral condyle fracture )

Sail sign

Figure 1: Measurement of apical angle of the anterior fat pad ≥ 20 degrees, concerning for sail sign. There is also a visible posterior fat pad. Case courtesy of Dr. Ian Bickle, Radiopaedia.org. Annotations by Daniel Ichwan, MD.

3.   Bones, Growth Plates, and Ossification Centers

Elbow x-ray

Figure 2: Lateral and AP x-rays of the elbow demonstrating humerus (green), radius (violet), and ulna (blue). Case courtesy of Dr. Jeremy Jones, Radiopaedia.org. Annotations by Daniel Ichwan, MD.

  • Immature bones with open growth plates (physes) are susceptible to injuries (Salter-Harris fractures) with important growth implications.
    • The Salter-Harris classification is as follows below:
      • Salter-Harris Type 1 (“Slipped”) – epiphysis (part of bone between the growth plate and adjacent joint) separates from metaphysis (neck portion of a long bone).
        • Pearl: Can appear radiographically normal, but tender on physical exam.
        • Requires splinting and ortho follow-up.
      • Type 2 (“Above”) – involves metaphysis (“above the physis”).
        • Requires splinting and ortho follow-up.
      • Type 3 (“Lower”) – involves epiphysis (“below the physis”).
        • Consult orthopedics in the department.
      • Type 4 (“Through”) – involves both the metaphysis and epiphysis.
        • Consult orthopedics in the department.
      • Type 5 (“Erasure”) – crushing of physis. May appear normal or focal narrowing of physis.
        • Consult orthopedics in the department

Figure 3: Salter-Harris Classification. Case courtesy of Dr. Matt Skalski, Radiopaedia.org.

  • Pediatric bones have a stronger periosteum than the underlying incompletely ossified bones.
    • Watch out for bowing, torus, greenstick, or avulsion injuries.
  • Trace each bone’s cortex carefully on both AP and lateral views.
  • Pay close attention to all aspects of the humerus, radius, and ulna.
  • Locate each expected ossification center per the patient’s age.
    • If there is one missing or seemingly prematurely present, consider a fracture.

Figure 4: Ossification centers on (a) AP pediatric elbow x-ray (case courtesy of Dr. Leonardo Lustosa, Radiopaedia.org) and (b) lateral pediatric elbow x-ray. Note that not all ossification centers are visible in this view (case courtesy of Dr. Ian Bickle, Radiopaedia.org. Figure 6 (b) annotations by Daniel Ichwan, MD

 

Table 1: Order and timing of appearance of elbow ossification centers. Some people remember this order by using the mnemonic “CRITOE”: capitellum, radial head, internal (medial) epicondyle, trochlea, olecranon, and external (lateral) epicondyle.

4.  Consider an Additional View

Oblique View

  • When: Sometimes included as the 3rd view in a series
  • Why: This is better at seeing the radiocapitellar joint, medial epicondyle, radioulnar joint, and coronoid process. Consider obtaining this view if there is a high suspicion for a subtle lateral condyle fracture or radial head fracture.

Elbow xray

Figure 6: Lateral oblique x-ray of the elbow. Case courtesy of Dr. Craig Hacking, Radiopaedia.org.

X-rays of Contralateral Elbow

  • Given variation among patients, sometimes it might be necessary to image the contralateral extremity to clarify whether the questionable finding is pathologic or actually normal.

References

  1. Schiller, P. et al. Radiology Education in Medical School and Residency. The views and needs of program directors. Academic Radiology, Vol 25, No 10, October 2018. PMID: 29748045
  2. DeFroda SF, Hansen H, Gil JA, Hawari AH, Cruz AI Jr. Radiographic Evaluation of Common Pediatric Elbow Injuries. Orthop Rev (Pavia). 2017;9(1):7030. Published 2017 Feb 20. PMID: 28286625
  3. Chan O. Introduction: ABCs and Rules of 2. In: ABC of Emergency Radiology. John Wiley & Sons, Ltd; 2013:1-10.
  4. Blumberg SM, Kunkov S, Crain EF, Goldman HS. The predictive value of a normal radiographic anterior fat pad sign following elbow trauma in children. Pediatr Emerg Care. 2011 Jul;27(7):596-600. PMID: 21712751
  5. Black KL, Duffy C, Hopkins-Mann C, Ogunnaiki-Joseph D, Moro-Sutherland D. Musculoskeletal Disorders in Children. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. McGraw-Hill; Accessed December 22, 2020. https://accessmedicine.mhmedical.com/content.aspx?bookid=1658&sectionid=109408415
By |2021-05-15T12:49:15-07:00Mar 19, 2021|EMRad, Orthopedic, Pediatrics, Radiology, Trauma|

Computerized Adaptive Screen for Suicidal Youth (CASSY) study

CASSY PECARN suicide screening tool

Adolescent suicide rates in the United States, partly augmented by the COVID-19 pandemic, are steadily increasing [1, 2]. A commonly used screening tool is the 4-question Ask Suicide-Screening Questions (ASQ) instrument, which has a sensitivity and specificity of 60% and 92.7%, respectively, in predicting suicide-related events within 3 months. This was derived from a retrospective study of 15,003 pediatric patients (age 10-18 years) [3]. Given the morbidity and mortality associated with suicide attempts, is there a better screening tool with a higher sensitivity than 60%, while also maintaining adequate specificity? A higher sensitivity rate ensures that we have fewer misses.

The CASSY tool

In JAMA Psychiatry 2021, the Pediatric Emergency Care Applied Research Network (PECARN) researchers report derivation and external validation data for their suicide screening tool, called the Computerized Adaptive Screen for Suicidal Youth (CASSY) [4]. This publication was actually two studies in one: a derivation of the tool and then an external validation.

Terminology

This paper assumes that the reader understands certain predictive analytics methodologies and test design concepts. Let’s briefly review some of the foundational terminology used:

  • Item response theory [Wikipedia]: “It is a theory of testing based on the relationship between individuals’ performances on a test item and the test takers’ levels of performance on an overall measure of the ability that item was designed to measure.” Of note, each item may be weighted differently based on how well it correlates with the overall outcome measure, which in this study was suicide attempt within 3 months.
  • Computerized adaptive testing [Wikipedia]: This computer testing strategy, also known as tailored testing, presents questions based on the individual’s response to a prior question.
  • Receiver operator characteristics (ROC): “The performance of a diagnostic test in the case of a binary predictor can be evaluated using the measures of sensitivity and specificity. However, in many instances, we encounter predictors that are measured on a continuous or ordinal scale. In such cases, it is desirable to assess performance of a diagnostic test over the range of possible cutpoints for the predictor variable. This is achieved by a receiver operating characteristic (ROC) curve that includes all the possible decision thresholds from a diagnostic test result.” [5] In other words, test sensitivities can be calculated for set specificities of, for instance, 70%, 80%, and 90%. Based on the purpose of the diagnostic test, the binary predictor threshold would be set accordingly.
  • Area under the curve (AUC): Calculating the AUC for the ROC is an effective means to determine a diagnostic test’s accuracy. The AUC ranges from 0 to 1 with 0.5 meaning no discrimination (i.e., the test can not diagnose patients with and without the disease based on the test). Generally, an AUC value of 0.7-0.8 is acceptable, 0.8 to 0.9 is excellent, and >0.9 is outstanding [5].

Study 1: CASSY derivation

A total of 6,536 adolescents (age 12-17 years) from 13 PECARN emergency departments were enrolled and a subset were randomly received follow-up in 3 months to assess for a suicide attempt. These patients responded to 92 questions on a computer tablet. Using a multidimensional item response theory approach, the more correlated questions (72) were used to create the CASSY tool.

Test characteristic results:

  • AUC: 0.89 (excellent)
  • Using the ROC curve, the CASSY sensitivity was 83% and 61% for the fixed specificity of 80% and 90%, respectively.

Study 2: CASSY validation

A total of 4,050 adolescents from 14 PECARN emergency departments were enrolled, and all received 3-month follow-up assessing for a suicide attempt. These patients completed the CASSY tool, as well as a subset of questions from study 1 for comparison. The frequency of questions used in the adaptive screen are itemized in the paper.

Test characteristic results:

  • AUC 0.87 (excellent)
  • Using the ROC curve and at the 80% specificity cutoff from study 1, the CASSY sensitivity was 82.4% and specificity was 72.5%.

CASSY figure ROC

Limitations

Although there was strong study rigor by deriving and independently validating the tool in separate, multicenter populations, it should be noted that generalizability may be affected.

  1. The study was conducted in academic pediatric emergency departments.
  2. There was quite a few patients who were lost to follow up (27.1% in study 1, 30.5% in study 2), which may have skewed the results.
  3. Selection bias may have occurred because of patients declining to participate in the study (62% enrollment rate in study 1, 62.2% in study 2)

Bottom line

The CASSY tool accurately serves as a screening predictive tool for adolescents at risk for a suicide attempt in 3 months. Rather than having patients complete exhaustively long (and practically unfeasible) screening questions in the emergency department, this computerized adaptive tool required only a mean of 11 questions, which took a median time of 1.4 minutes (IQR 0.98-2.06 minutes) to complete.

How can you implement CASSY in your emergency department?

We asked the authors this question, and the answer is in the podcast below.

Podcast

Listen more with author Dr. Jacqueline Grupp-Phelan talking with ALiEM podcast host, Dr. Dina Wallin, about this landmark paper and behind-the-scenes issues not included on the paper.

This blog post was expert peer-reviewed by Drs. King and Grupp-Phelan, who authored the paper.

References

  1. Hill RM, Rufino K, Kurian S, Saxena J, Saxena K, Williams L. Suicide Ideation and Attempts in a Pediatric Emergency Department Before and During COVID-19 [published online ahead of print, 2020 Dec 16]. Pediatrics. 2020;e2020029280. PMID: 33328339
  2. Centers for Disease Control and Prevention. Web-based Injury Statistics Query and Reporting System (WISQARS). Published 2020.
  3. DeVylder JE,Ryan TC, Cwik M, et al. Assessment of selective and universal screening for suicide risk in a pediatric emergency department. JAMA Netw Open. 2019;2(10):e1914070-e1914070. PMID 31651971
  4. King CA, Brent D, Grupp-Phelan J, et al. Prospective Development and Validation of the Computerized Adaptive Screen for Suicidal Youth [published online ahead of print, 2021 Feb 3]. JAMA Psychiatry. 2021; 10.1001/jamapsychiatry.2020.4576. doi:10.1001/jamapsychiatry.2020.4576. PMID 33533908
  5. Mandrekar JN. Receiver operating characteristic curve in diagnostic test assessment. J Thorac Oncol. 2010;5(9):1315-1316. doi:10.1097/JTO. 0b013e3181ec173d

Listen to all the PECARN podcasts

PEM Pearls: To Scan or Not to Scan? CT Abdomen in Children with Blunt Torso Trauma

blunt torso traumaAn 18-month-old female with no past medical history is brought in by ambulance after a motor vehicle collision (MVC) at highway speed, restrained in an appropriate car seat. Mom was also brought in after delayed extrication with an obvious femur deformity. EMS reports that the patient had emesis on the scene, was fearful but calm, and has been moving all extremities.

Vitals per EMS: HR 120, BP 100/60, RR 30, SpO2 99%, Temp 36.5 C

Initial Exam:

  • General: crying
  • Neuro: Glasgow Coma Scale (GCS) of 13 (eyes shut unless talked to, crying spontaneously, moving all extremities)
  • MSK: atraumatic chest, erythema on the left leg
  • Abdomen: without tenderness

Blunt Torso/Abdominal Trauma

An intra-abdominal injury (IAI) is considered to be any radiographically or surgically apparent injury to an intra-abdominal structure (urinary tract, gastrointestinal tract, spleen, liver, pancreas, gallbladder, adrenal gland, vasculature, and fascia). An intra-abdominal injury requiring intervention (IAI-I) is any IAI that causes death or requires an intervention such as laparotomy, angiographic embolization, blood transfusion, or even admission for intravenous fluids [1].

Despite our curiosity and desire to diagnose all injuries, emergency medicine teams must focus on recognizing IAI-I and tailor their workup accordingly given the negative consequences of excessive workup and treatment of stable IAIs (e.g., unnecessary splenectomies, hepatectomies, increased length of stay, radiation, and increased medical costs/resources).

Although the incidence of pediatric blunt torso trauma in the United States was 110,525 cases in 2016, the prevalence of IAI has been quoted to be as low as 6.3%; more importantly, the prevalence of IAI-I is less than 2% [1]. Non-pediatric level 1 trauma centers were more likely to use computed tomography (CT) in pediatric trauma patients compared to pediatric trauma centers, even after adjusting for injury severity [2].

Clinical Decision Rule

The Pediatric Emergency Care Applied Research Network (PECARN) conducted a prospective study of over 12,000 children ages 0-18 years presenting to pediatric and general EDs with blunt torso trauma. Significant predictors of IAI-I were low GCS, abdominal tenderness, abdominal wall trauma, thoracic wall trauma, decreased breath sounds, and vomiting. The authors developed a prediction rule with a sensitivity of 97% (93.7, 98.9) and a negative predictive value of 99.9% (99.7, 1.00) [1]. External validation had similar sensitivity (99% 96-100%) reinforcing the utility of this clinical decision rule (CDR) in identifying low-risk individuals and decrease the use of CT [4].

In comparison to other CDRs, this rule does not include a gestalt variable but outperforms clinical gestalt with a lower miss rate (6 compared to 23) [5]. Of note, this prediction rule is not a two-way tool and was created only to determine individuals at low risk of IAI-I, rather than to assist providers in deciding who needs a CT scan.

 

IAI

Adapted from Holmes JF et al 2013 [1]

 

Reviewing the cases missed by the prediction rule in the initial study, possible clinical findings that could be captured with adjuncts, such as labs and imaging, include:

  • Gross hematuria
  • Microscopic hematuria (Red Blood Cells on Urinalysis)
  • Elevated AST/ALT
  • Rib fracture

Adjuncts

No single test effectively screens for IAI-I or IAI, but additional testing can increase the index of concern in cases that already have a higher pre-test probability (individuals who have any of the variables factored into the prediction rule). The following adjuncts can be considered for children who are not deemed very low risk.

Labs

  • Hematocrit <30% [3,7-8]
  • AST>200 U/L, ALT>125U/L [3,7, 9-10]
  • Lipase >100 U/L [9,11-12]
  • UA Gross hematuria [12-17]

Focused Assessment with Sonography for Trauma (FAST)

  • The diagnostic role of a FAST in pediatric trauma is less established than in adult trauma [18].
  • Application of FAST increases as provider suspicion for IAI increases [19].
  • As an adjunct to the clinical exam, FAST can be incorporated into decision making for selected cases of increased IAI concern [20].

Chest X-ray (CXR)

  • Injuries noted on a CXR may contribute to increased concern for IAI depending on location, mechanism, and type of injury [21].

Review of Case

Returning to our case, findings of concern include her GCS of 13 and reported emesis. Although it was a high-speed MVC and may represent a more severe mechanism, this variable was not found to be a predictor of IAI-I and should not in isolation inform your evaluation of her abdominal injury.

Application of the PECARN CDR demonstrates that the patient is not at very low risk for IAI-I. Labs and a FAST are performed and medications are given for symptom control.

The patient’s results are:

Labs:

  • HCT 35%
  • Lipase 20 U/L
  • AST 23 U/L, ALT 30 U/L
  • UA: no gross hematuria

FAST: Negative

On re-evaluation after ondansetron and acetaminophen, the patient has a GCS of 15 and is excitedly playing with her new teddy bear from the fire department while sipping apple juice. The patient is safely discharged home with her dad after a very frightening experience without unnecessary costs or radiation.

Take-Home Points

  • While blunt pediatric abdominal trauma has a high incidence, the prevalence of IAI-I is rather low.
  • The PECARN prediction rule for blunt torso trauma can identify patients that are very-low-risk for an IAI-I.
  • Notably, the mechanism of injury is not a predictable factor in determining IAI-I.
  • Clinicians should consider the use of labs, FAST, and CXR for risk stratification of patients that are not found to be very-low-risk.

Read more pediatric emergency medicine topics as part of the PEM Pearls Series on ALiEM.

References

  1. Holmes JF, Lillis K, Monroe D, et al. Identifying children at very low risk of clinically important blunt abdominal injuries. Ann Emerg Med. 2013;62(2):107-116.e2. doi:10.1016/j.annemergmed.2012.11.009. PMID: 23375510
  2. Marin JR, Wang L, Winger DG, Mannix RC. Variation in Computed Tomography Imaging for Pediatric Injury-Related Emergency Visits. J Pediatr. 2015 Oct;167(4):897-904.e3. doi: 10.1016/j.jpeds.2015.06.052. PMID: 26233603
  3. Holmes JF, Sokolove PE, Brant WE, et al. Identification of children with intra-abdominal injuries after blunt trauma. Ann Emerg Med. 2002;39(5):500-509. doi:10.1067/mem.2002.122900. PMID: 11973557
  4. Springer E, Frazier SB, Arnold DH, Vukovic AA. External validation of a clinical prediction rule for very low risk pediatric blunt abdominal trauma. Am J Emerg Med. 2019 Sep;37(9):1643-1648. doi: 10.1016/j.ajem.2018.11.031. PMID: 30502218.
  5. Mahajan P, Kuppermann N, Tunik M, et al. Comparison of Clinician Suspicion Versus a Clinical Prediction Rule in Identifying Children at Risk for Intra-abdominal Injuries After Blunt Torso Trauma. Acad Emerg Med. 2015;22(9):1034-1041. doi:10.1111/acem.12739. PMID: 26302354
  6. Nishijima DK, Yang Z, Clark JA, Kuppermann N, Holmes JF, Melnikow J. A cost-effectiveness analysis comparing a clinical decision rule versus usual care to risk stratify children for intraabdominal injury after blunt torso trauma. Acad Emerg Med. 2013;20(11):1131-1138. doi:10.1111/acem.12251. PMID: 24238315
  7. Taylor GA, Eichelberger MR, O’Donnell R, Bowman L. Indications for computed tomography in children with blunt abdominal trauma [published correction appears in Ann Surg 1992 Jul;216(1):99]. Ann Surg. 1991;213(3):212-218. doi:10.1097/00000658-199103000-00005. PMID: 1998402
  8. Taylor GA, O’Donnell R, Sivit CJ, Eichelberger MR. Abdominal injury score: a clinical score for the assignment of risk in children after blunt trauma. Radiology. 1994;190(3):689-694. doi:10.1148/radiology.190.3.8115612. PMID: 8115612
  9. Streck CJ, Vogel AM, Zhang J, et al. Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely. J Am Coll Surg. 2017;224(4):449-458.e3. doi:10.1016/j.jamcollsurg.2016.12.041. PMID: 28130170
  10. Streck CJ Jr, Jewett BM, Wahlquist AH, Gutierrez PS, Russell WS. Evaluation for intra-abdominal injury in children after blunt torso trauma: can we reduce unnecessary abdominal computed tomography by utilizing a clinical prediction model?. J Trauma Acute Care Surg. 2012;73(2):371-376. doi:10.1097/TA.0b013e31825840ab. PMID: 22846942
  11. Adamson WT, Hebra A, Thomas PB, Wagstaff P, Tagge EP, Othersen HB. Serum amylase and lipase alone are not cost-effective screening methods for pediatric pancreatic trauma. J Pediatr Surg. 2003;38(3):354-357. doi:10.1053/jpsu.2003.50107. PMID: 12632348
  12. Capraro AJ, Mooney D, Waltzman ML. The use of routine laboratory studies as screening tools in pediatric abdominal trauma. Pediatr Emerg Care. 2006;22(7):480-484. doi:10.1097/01.pec.0000227381.61390.d7. PMID: 16871106
  13. Mee SL, McAninch JW, Robinson AL, Auerbach PS, Carroll PR. Radiographic assessment of renal trauma: a 10-year prospective study of patient selection. J Urol. 1989;141(5):1095-1098. doi:10.1016/s0022-5347(17)41180-3. PMID: 2709493
  14. Morey, Allen F., et al. “Efficacy of Radiographic Imaging in Pediatric Blunt Renal Trauma.” Journal of Urology, vol. 156, no. 6, 1996, pp. 2014–2018., doi:10.1016/s0022-5347(01)65422-3.
  15. Brown SL, Haas C, Dinchman KH, Elder JS, Spirnak JP. Radiologic evaluation of pediatric blunt renal trauma in patients with microscopic hematuria. World J Surg. 2001;25(12):1557-1560. doi:10.1007/s00268-001-0149-6. PMID: 11775191
  16. Santucci RA, Langenburg SE, Zachareas MJ. Traumatic hematuria in children can be evaluated as in adults. J Urol. 2004;171(2 Pt 1):822-825. doi:10.1097/01.ju.0000108843.84303.a6. PMID: 14713834
  17. Levy JB, Baskin LS, Ewalt DH, et al. Nonoperative management of blunt pediatric major renal trauma. Urology. 1993;42(4):418-424. doi:10.1016/0090-4295(93)90373-i. PMID: 8212441
  18. Holmes JF, Gladman A, Chang CH. Performance of abdominal ultrasonography in pediatric blunt trauma patients: a meta-analysis. J Pediatr Surg. 2007 Sep;42(9):1588-94. doi: 10.1016/j.jpedsurg.2007.04.023. PMID: 17848254
  19. 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. PMID: 25159246
  20. Retzlaff T, Hirsch W, Till H, Rolle U. Is sonography reliable for the diagnosis of pediatric blunt abdominal trauma? J Pediatr Surg. 2010 May;45(5):912-5. doi: 10.1016/j.jpedsurg.2010.02.020. PMID: 20438925
  21. Holmes JF, Sokolove PE, Brant WE, Kuppermann N. A clinical decision rule for identifying children with thoracic injuries after blunt torso trauma. Ann Emerg Med. 2002 May;39(5):492-9. doi: 10.1067/mem.2002.122901. PMID: 11973556

Read more pediatric emergency medicine topics as part of the PEM Pearls Series on ALiEM.

Free eBook Announcement: Emergency Medicine Resident Simulation Curriculum for Pediatrics (EM ReSCu Peds)

emergency medicine resident simulation curriculum for pediatrics EM ReSCu Peds

 

The Emergency Medicine Resident Simulation Curriculum for Pediatrics (EM ReSCu Peds) is here! This free ebook contains 16 EM resident-tested, peer reviewed cases covering essential pediatric content identified through a robust modified Delphi process [1] with experts across the United States. Each chapter contains robust supporting materials to help educators prepare, execute, and debrief cases with residents at every level to help supplement the clinical experience.

Download the EM ReSCu Peds eBook

We request some basic demographic about you and how you plan to use the educational cases in the download form to provide us with necessary insights whether there is a need for such a resource.

A National Collaborative Effort

Cases were created and iteratively peer reviewed by members of 10 organizations represented in a national collaborative of EM, PEM, and simulation experts. Participating organizations included:

  • American Academy of Emergency Medicine
  • American Academy of Pediatrics
  • American College of Emergency Physicians
  • Council of Emergency Medicine Residency Directors
  • Emergency Medicine Residents’ Association
  • International Network for Simulation-based Pediatric Innovation, Research, & Education
  • International Pediatric Simulation Society
  • Pediatric Trauma Society
  • Society for Academic Emergency Medicine
  • Society for Simulation in Healthcare

In total, EM and PEM physicians from 44 institutions participated in the development process of this educational resource aimed at preparing EM residents to care for critically ill children.

 

Reference

  1. Mitzman J, Bank I, Burns RA, et al. A Modified Delphi Study to Prioritize Content for a Simulation-based Pediatric Curriculum for Emergency Medicine Residency Training Programs. AEM Educ Train. 2019;4(4):369-378. Published 2019 Dec 12. doi:10.1002/aet2.10412
By |2021-01-09T11:52:36-08:00Jan 12, 2021|Pediatrics, Simulation|
Go to Top