Rationale: Hydronephrosis caused by retroperitoneal hematoma after a seatbelt injury is a unique clinical entity.
Patient concerns: A 21-year-old man, who had been wearing a seatbelt, was brought to our hospital after a motor vehicle collision, complaining of abdominal pain. Computed tomography (CT) revealed retroperitoneal hematoma in the upper pelvic region. Since he was hemodynamically stable throughout admission, he was managed conservatively. Seventeen days after initial discharge, the patient revisited our emergency department due to right back pain.
Diagnoses: CT scans indicated retroperitoneal hematoma growth resulting in hydronephrosis of the right kidney.
Interventions: Laparoscopic drainage of the retroperitoneal hematoma was successfully performed.
Outcomes: His symptoms resolved after the surgery. Follow-up CT scans three months later demonstrated complete resolution of the hydronephrosis and retroperitoneal hematoma.
Lessons: Our case highlights a patient with delayed hydronephrosis because of retroperitoneal hematoma expansion after a seatbelt injury.