Postcatheterization retroperitoneal hematoma due to spontaneous lumbar arterial hemorrhage.

A patient developed retroperitoneal hemorrhage after cardiac catheterization, initially thought to be a complication of the puncture. Diagnostic evaluation revealed the source to be spontaneous bleeding from a lumber artery, which was successfully embolized. Spontaneous hemorrhage is a recognized complication of anticoagulation therapy and must be considered in the differential diagnosis even in the face of a seemingly obvious source of bleeding.