The "bladder sign"--an important early marker of retroperitoneal hemorrhage.

Retroperitoneal hemorrhage remains one of the major complications of cardiac and peripheral vascular catheterization. Its high associated morbidity and mortality require vigilance and early intervention. We report six cases of retroperitoneal hemorrhage featuring a "bladder sign." The compression of the bladder described in this series can be visualized on the incidental cystogram that results from contrast given during catheterization. Its significance as a highly specific marker of retroperitoneal hemorrhage should be appreciated.