Renal artery aneurysms.

The various types of renal artery aneurysms are described, the most common one being the congenital saccular aneurysm. Usually asymptomatic it may be associated with hypertension and generally undergoes atherosclerotic degeneration. An arteriovenous fistula may form and rupture into the renal pelvis or retroperitoneal space in some rare instances. Small, well calcified saccular aneurysms should be left alone and followed; larger, incompletely calcified or non-calcified aneurysms should be removed. Fusiform aneurysmal dilatation of the renal artery occurs distal to a focal fibromuscular dysplastic stenosis. This type is almost invariably found in hypertensive young people. Thrombosis of a branch may occur distal to the aneurysm. These aneurysms should be treated surgically, usually by excision of the stenotic area and its aneurysm, and anastomosis of branches back to the main renal artery. Dissecting aneurysms of the renal artery are the most damaging to the kidney. Complications are thrombosis of the branches, infarction of the kidney and a virulent form of hypertension. An operation should be done to correct the dissection and to remove part or all of the kidney when infarction is severe. Intrarenal arterial aneurysms are prone to hemorrhage and should be removed by local excision or partial nephrectomy.