Unilateral Renal Parenchymal Disease with Contralateral Renal Artery Stenosis of the Fibrodysplasia Type

In patients who have hypertension and a unilateral small kidney, hypertension may have either a vascular (renal artery stenosis) or nonvascular (urologic) cause. Generally, the hypertension can be attributed to the abnormal-sized kidney, and nephrectomy of the shrunken kidney or correction of the stenotic artery will result in the normalization of blood pressure. We report eight cases of hypertension in young women shown to have a small kidney by intravenous urography. The abnormal-sized kidney was considered to be due to either agenesis or dysplasia and reflux. Although the diseased kidney was thought to be the cause of the high blood pressure, these patients were unique in that they had a stenosis of the contralateral renal artery of the fibrodysplasia type, which was predominantly localized in the distal part of the artery and frequently extended into the peripheral branches. Successful anatomic correction of the stenotic artery without surgery on the contralateral small kidney resulted in the normalization of blood pressure. This previously unrecognized combination of parenchymal disease of one kidney and renal artery stenosis of the fibrodysplasia type on the contralateral side should be considered in patients with hypertension and a unilateral small kidney. Such recognition could prevent the unnecessary treatment of these patients with an angiotensin-converting enzyme inhibitor or nephrectomy.