CAT Question: Can bedside US accurately diagnose skull fractures in children < 4 years old? 

Background: 

• TBI in children < 14 y/o accounts for about half a million ED visits, 35,000 hospitalizations, and > 2000 deaths annually1
• The highest rate of TBI-related ED visits is in children 0-4 years old1
• The rate of intracranial injury in children with head trauma is 4-12% and the rate may be higher in children ages 0-2 years old2
• Some studies estimate up to a 20-fold increased risk of underlying intracranial injury with overlying skull fracture3 
• CT is the current gold standard test for diagnosing skull fractures but comes with risks including radiation exposure, need for sedation, and increased costs

 Ultrasound has been shown to accurately diagnose fractures in other bones in the body. It is quick, easy, and cost-effective.

Bottom Line: 

• Ultrasound diagnosed skull fractures with good sensitivity and specificity. However, neither study argued it should replace CT scan as the screening imaging method of choice for pediatric skull fractures. 
• POCUS could have utility in resource poor settings as a screening tool to determine which children need to be transferred to a center with a CT scanner. It could also be used as a triaging tool to determine which children should take priority to go to the CT scanner when multiple children have head injuries. 

Study 1: Choi JY, et al. Accuracy of Bedside Ultrasound for the Diagnosis of Skull Fractures in Children Aged 0 to 4 years. Pediatr Emerg Care 2020; 36(5);268-273

• Objective: To investigate the accuracy of bedside US performed by an EM physician in diagnosing skull fractures in children ages 0-4 years old compared to head CT.
• Single center, prospective study including children ages 0-4 with a history of head trauma. 87 children were enrolled. Children received both a skull ultrasound performed and read by an Emergency Medicine fellow and a head CT read by an attending radiologist. Both physicians were blinded to the results of the other test. 
• Results
• 13 (14.9%) had skull fx according to CT
• US sensitivity = 76.9%
• US specificity = 100%
• PPV of US = 100%
• NPV of US = 96.1%
• Limitations: 
• Varying levels of EM physician training with ultrasound (user dependent test)
• Small sample size
• Only included ages 0-4, which limits generalizability 

Study 2: Parri N, et al. Point-of-Care Ultrasound for the Diagnosis of Skull Fractures in Children Younger than Two Years of Age. J Pediatr. 2018;196;230-236

• Objective:To determine the accuracy of bedside ultrasound of the skull in identifying fractures in children < 2 years old with signs of head trauma and ability of ultrasound to determine the type and depth of fracture. 
• Multi-center (5 pediatric EDs), prospective study including children ages 0-2 years old with a history of head trauma. 115 children were enrolled. Children received both a skull ultrasound performed and read by a physician (including PEM physicians, general EM physicians, pediatricians, and residents with attending supervision) and a head CT read by an attending radiologist. Both physicians were blinded to the results of the other test. Physicians were encouraged to use the PECARN decision rule to determine which children received CT scans.
• Results: 
• 88 (76.5%) children had skull fracture according to CT
• US sensitivity = 90.9%
• US specificity = 85.2%
• PPV of US = 95.2%
• NPV of US = 74.2%
• Limitations: 
• Varying levels of physician training 

References

• Faul M, Xu L,WaldMM, et al. Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths 2002–2006.Centers for Disease Control and Prevention, National Center for Injury. Prevention and Control: Atlanta GA; 2010.
• Osmond MH, Klassen TP,Wells GA, et al. Pediatric Emergency Research, Canada (PERC) Head Injury Study Group. CATCH: a clinical decision rule for the use of computed tomography in children with minor head injury.CMAJ. 2010;182:341–348.
• Dunning J, Batchelor J, Stratford-Smith P, et al. A meta-analysis of variables that predict significant intracranial injury in minor head trauma. Arch Dis Child. 2004;89:653–659.
• Brenner DJ. Estimating cancer risks from pediatric CT: going from the qualitative to the quantitative. Pediatr Radiol. 2002;32:228–231.
• Gruskin KD, Schutzman SA. Head Trauma in children younger than 2 years: are there predictors for complications? Arch Pediatr Adolesc Med 1999;153:15-20.
• Choi JY, et al. Accuracy of Bedside Ultrasound for the Diagnosis of Skull Fractures in Children Aged 0 to 4 years. Pediatr Emerg Care 2020; 36(5);268-273
• Parri N, et al. Point-of-Care Ultrasound for the Diagnosis of Skull Fractures in Children Younger than Two Years of Age. J Pediatr. 2018;196;230-236