Traumatic renal injury - AAST grade IV injury


There is an injury to the right kidney with a perinephric hematoma.

The patient was recalled for a delayed study, 30 minutes after the initial images had been reviewed and the amount of extravasated contrast from the urinary system was increased. 

Urinary extravasation classifies this as a grade IV injury on the American Association for the Surgery of Trauma (AAST) renal injury scale. 

This case also illustrates the importance of appropriate protocolling of trauma CT - when a renal injury is clinically suspected especially in the presence of hematuria, this should lead to either an automatic acquisition of an excretory phase study or at least a 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 inuries and pneumothoraces.