There is a perinephric hematoma and blood in the collecting system. The urinary extravasation classifies this is as a grade IV injury on the American Association for the Surgery of Trauma (AAST) renal injury scale. A conservative pathway was followed and subsequent ultrasound imaging (not shown here) showed a normal right kidney.

This case also illustrates the importance of appropriate protocolling of trauma CT - the presence of hematuria following a flank injury should lead to either the automatic acquisition of an excretory phase study or at the least contemporaneous review of the portal venous phase images to allow a prompt decision about further imaging to be made. Best practice also dictates imaging of the chest to look for rib and lung injuries and pneumothoraces.