Pediatric patients are at a higher risk of blunt renal injury due to multiple anatomic features, include relatively less protective perinephric fat and surrounding musculature, and larger size of the kidneys in relation to the abdomen compared to their adult counterparts (1). For this reason, it is important to keep a high clinical suspicion for renal injury in the pediatric patient with blunt abdominal trauma, particularly in those with lower rib fractures, direct injury, flank ecchymosis and/or tenderness, rapid deceleration injury, or other significant traumatic mechanism (2). Despite the risk of radiation exposure, the preferred imaging modality for the diagnosis of renal injury in pediatric patients is computed tomography (similar to adults). Studies evaluating the utility of renal ultrasound have demonstrated poor sensitivity with a decreased likelihood of diagnosing low-grade injuries. While ultrasound may be a useful screening tool to evaluate for severe injury, it should not be used to rule out traumatic injury (1). Take home point: Keep a high suspicion for renal injury in pediatric patients with blunt abdominal trauma and confirm the diagnosis with computed tomography of the abdomen and pelvis with contrast.
(1) Fraser, J.D., Aguayo, P., Ostlie, D.J. et al. Pediatr Surg Int (2009) 25: 125. https://doi.org/10.1007/s00383-008-2316-4 (2) Gerstenbluth RE, Spirnak JP, Elder JS. Sports participation and high grade renal injuries in children. J Urol 2002; 168:2575.