Delayed Presentation of a Traumatic Retroperitoneal Hematoma With Low-Grade Renal Injury After a Low-Speed Electric Scooter Handlebar Impact in a Child: A Case Report

Electric scooters (e-scooters) are an increasingly common cause of injury in children, but their capacity to cause occult intra-abdominal injury is under-recognized. We report a seven-year-old boy with type 1 diabetes mellitus who presented to the pediatric emergency department seven days after a witnessed low-speed fall from an electric scooter with a direct handlebar impact to the right abdomen. He was initially asymptomatic, developed right-sided abdominal pain on the second day after injury, and became progressively pale. On arrival, he was hemodynamically stable, with right upper quadrant tenderness and fullness, no peritonism, and no external signs of injury. Bedside sonography showed no free intraperitoneal fluid, but marked anemia prompted contrast-enhanced computed tomography (CT), which demonstrated a large right retroperitoneal hematoma extending from the subhepatic region into the right hemipelvis, a right perinephric hematoma, and no active contrast extravasation. Targeted renal Doppler ultrasonography identified a small inferior-pole cortical laceration that was not discernible on computed tomography, and the renal injury was classified as low grade. He received a single red blood cell transfusion, was managed nonoperatively in a pediatric high-dependency unit, and was discharged in stable condition on day 5. This case shows that a low-speed handlebar impact without external signs can cause major retroperitoneal bleeding with a delayed presentation, that unexplained anemia after blunt abdominal trauma warrants cross-sectional imaging despite normal vital signs and negative bedside sonography, and that large retroperitoneal hematomas can be managed nonoperatively in stable children without active extravasation.