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From Collision to Clarity: PECARN cervical spine injury prediction rule for injured children

PECARN cervical spine injury prediction tool featured image (adapted from Midjourney)

For years, adult literature has provided clear guidelines for cervical spine imaging through the NEXUS and Canadian C-spine Rule (CCR) tools. These have been invaluable in helping clinicians decide when to image the neck in trauma patients. Similarly, the Pediatric Emergency Care Applied Research Network (PECARN) has developed robust tools for assessing blunt head trauma in children. However, until now, there has been a gap in guidance for clinicians managing pediatric patients at risk for cervical spine injuries.

Case Scenario: What would you do?

A 10-year-old boy presents to the emergency department (ED) after a high-speed motor vehicle collision. He complains of neck pain and is reluctant to move his head. The child’s mother is extremely worried, fearing the worst after witnessing the collision.

The Problem

Cervical spine injuries in children, while uncommon, can be devastating if not identified and treated promptly. Emergency physicians often face the challenge of deciding whether to proceed with imaging, given the potential risks associated with ionizing radiation from CT scans. The lack of clear guidelines specifically tailored for pediatric patients has historically led to either overuse of imaging, with its associated risks, or underuse, with the risk of missed injuries.

PECARN Cervical Spine Injury Prediction Rule

On June 4, 2024, Lancet published “PECARN prediction rule for cervical spine imaging of children presenting to the emergency department with blunt trauma: a multicentre prospective observational study.” This study proposes a new clinical prediction rule to guide imaging decisions for pediatric cervical spine injuries.

The study enrolled 22,430 children, aged 0–17 years, presenting with blunt trauma across 18 PECARN-affiliated ED in the US. About half were in the derivation and half in the validation cohort. The researchers derived and validated a clinical prediction rule using data from these children, which identified key risk factors for cervical spine injury, divided into high-risk and non-negligible (intermediate) risk factors.

High Risk (>12.1% risk of injury) -> Consider CT

  • Altered mental status (GCS 3-8 or AVPU = U)
  • Abnormal airway
  • Breathing
  • Circulation findings
  • Focal neurological deficits

Intermediate Risk (2.8% risk of injury) -> Consider X-Rays

  • Neck pain or midline neck tenderness
  • Mental status: GCS 9-14, AVPU = V or P, or other signs of altered mental status
  • Substantial head or torso injury

Definition on Cervical Spine Injury

  • Fractures or ligamentous injuries of the cervical spine
  • Cervical intraspinal hemorrhage
  • Cerebral artery injury
  • Cervical spinal cord injury, including
    • Changes in the cervical spinal cord on MRI
    • Cervical spinal cord injury without radiographic association
PECARN Cervical Spine Injury Prediction Tool

PECARN Cervical Spine Injury Prediction Tool (Download full sized PDF at PECARN site)

The prediction rule had strong test characteristics with 94.3% sensitivity and 99.9% negative predictive value, indicating that it can reliably identify children who do not need imaging, thus avoiding unnecessary radiation exposure. This evidence-based approach to pediatric trauma care would have reduced the number of CT scans by more than 50% without missing clinically relevant injuries.

Case Example Resolution

Using the PECARN cervical spine injury prediction rule, the attending physician evaluates the boy and finds that he does not exhibit any high-risk factors. However, because he reports neck pain and has midline neck tenderness on exam (intermediate risk), the rule recommends that the cervical spine can not be clinically cleared. It also suggests plain x-rays and not a CT scan. This differs from the adult population whereby CT scan imaging is often the first choice for diagnostic testing.

The x-rays reveal no evidence of cervical spine injury, and the boy is cleared with instructions for follow-up care. This approach not only alleviated the mother’s anxiety but also avoided unnecessary radiation exposure for the child.

Reference

Leonard JC, Harding M, Cook LJ, et al. PECARN prediction rule for cervical spine imaging of children presenting to the emergency department with blunt trauma: a multicentre prospective observational study. Lancet Child Adolesc Health. 2024;8(7):482-490. doi:10.1016/S2352-4642(24)00104-4. PMID 38843852

By |2026-01-08T21:25:20-08:00Jun 10, 2024|Pediatrics, Radiology, Trauma|
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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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ALiEM AIR Series | Psychosocial Module 2024

Welcome to the AIR Psychosocial Module! After carefully reviewing all relevant posts in the past 12 months from the top 50 sites of the Digital Impact Factor [1], the ALiEM AIR Team is proud to present the highest quality online content related to related to psychosocial emergencies in the Emergency Department. 3 blog posts met our standard of online excellence and were approved for residency training by the AIR Series Board. More specifically, we identified 1 AIR and 2 Honorable Mentions. We recommend programs give 1 hours of III credit for this module.

AIR Stamp of Approval and Honorable Mentions

In an effort to truly emphasize the highest quality posts, we have 2 subsets of recommended resources. The AIR stamp of approval is awarded only to posts scoring above a strict scoring cut-off of ≥30 points (out of 35 total), based on our scoring instrument. The other subset is for “Honorable Mention” posts. These posts have been flagged by and agreed upon by AIR Board members as worthwhile, accurate, unbiased, and appropriately referenced despite an average score.

Take the AIR Psychosocial Module at ALiEMU

Interested in taking the AIR quiz for fun or asynchronous (Individualized Interactive Instruction) credit? Please go to the above link. You will need to create a free, 1-time login account.

Highlighted Quality Posts: Psychosocial

SiteArticleAuthorDateLabel
Rebel EMLow Dose vs Standard Dose Take-Home Buprenorphine From the EDTara Persaud Holmes, MD, MBA5 June 2023AIR
Don’t Forget the BubblesMedical Emergencies in Eating DisordersOwen Hibberd, Kat Priddis29 Sep 2023HM
RCEM LearningAcute DystoniaEsther Wilson12 Aug 2023HM

(AIR = Approved Instructional Resource; HM = Honorable Mention)

If you have any questions or comments on the AIR series, or this AIR module, please contact us!

Lin M, Phipps M, Chan TM, et al. Digital Impact Factor: A Quality Index for Educational Blogs and Podcasts in Emergency Medicine and Critical Care. Ann Emerg Med. 2023;82(1):55-65. doi:10.1016/j.annemergmed.2023.02.011, PMID 36967275

By |2024-04-30T10:28:32-07:00May 8, 2024|Approved Instructional Resources (AIR series), Psychiatry|
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ALiEM AIR Series | Renal Module (2023)

Welcome to the AIR Renal/GU Module! After carefully reviewing all relevant posts in the past 12 months from the top 50 sites of the Digital Impact Factor [1], the ALiEM AIR Team is proud to present the highest quality online content related to related to renal / GU emergencies in the Emergency Department. 6 blog posts met our standard of online excellence and were approved for residency training by the AIR Series Board. More specifically, we identified 3 AIR and 3 Honorable Mentions. We recommend programs give 3 hours of III credit for this module.

AIR Stamp of Approval and Honorable Mentions

In an effort to truly emphasize the highest quality posts, we have 2 subsets of recommended resources. The AIR stamp of approval is awarded only to posts scoring above a strict scoring cut-off of ≥30 points (out of 35 total), based on our scoring instrument. The other subset is for “Honorable Mention” posts. These posts have been flagged by and agreed upon by AIR Board members as worthwhile, accurate, unbiased, and appropriately referenced despite an average score.

Take the AIR Renal/GU Module at ALiEMU

Interested in taking the AIR quiz for fun or asynchronous (Individualized Interactive Instruction) credit? Please go to the above link. You will need to create a free, 1-time login account.

Highlighted Quality Posts: Renal / GU

SiteArticleAuthorDateLabel
EMCritAcute Kidney InjuryJosh FarkasMarch, 16, 2023AIR
EMCrit Hepatorenal SyndromeJosh FarkasApril 3, 2023AIR
EM DocsUrine trouble: approach to pediatric UTIJoe RaveraDecember 7, 2022HM
EM DocsTesticular TorsionBrit LongAugust 8, 2023HM
EM OttawaTesticular torsionAlex ViauJuly 27, 2023HM

(AIR = Approved Instructional Resource; HM = Honorable Mention)

 

If you have any questions or comments on the AIR series, or this AIR module, please contact us!

 

Reference

  1. Lin M, Phipps M, Chan TM, et al. Digital Impact Factor: A Quality Index for Educational Blogs and Podcasts in Emergency Medicine and Critical Care. Ann Emerg Med. 2023;82(1):55-65. doi:10.1016/j.annemergmed.2023.02.011, PMID 36967275

 

By |2024-04-30T10:31:18-07:00May 2, 2024|Approved Instructional Resources (AIR series), Genitourinary, Renal|
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