Unilateral Reflux Nephropathy with Contralateral Renal Artery Stenosis Due to Fibromuscular Hyperplasia

Dr. Ross R. Bailey Department of Nephrology, Christchurch Hospital, Christchurch (New Zealand) Dear Sir, The finding of a unilateral small kidney and a contralateral hypertrophied kidney in a patient with hypertension generally implicates the small kidney in the pathogenesis of the hypertension, whether it be of a vascular or non-vascular (parenchymal) aetiology. Recently there have been two reports [1,2] of hypertensive patients with a unilateral small kidney where the latter was thought to be the cause of the high blood pressure, but the patients were found to have a distal stenosis of the contralateral renal artery due to fibromuscular hyperplasia. We report a further such case: A 40-year-old woman was found to have persistent hypertension and was commenced on enalapril 10 mg daily. Prior to treatment the plasma creatinine was 0.08 mmol/l. Ten years previously she had suffered acute pyelonephritis, and an intravenous urogram had shown a small irregularly scarred right kidney characteristic of reflux nephropathy. The contralateral kidney showed compensatory hypertrophy. Four months after starting enalapril she presented with fever, right-loin pain, and a systemic illness and was supected of having acute pyelonephritis. She was started on antibiotics, but 2 days later was no better, and routine blood tests included a plasma creatinine level of 0.16 mmol/l. Three days later she had not improved, and the plasma creatinine had increased to 0.44 mmol/l. Enalapril was discontinued and she was hospitalized. On admission she was apyrexial, had no urinary tract symptoms, and the blood pressure was 170/114 mm Hg. Investigations: A midstream urine specimen showed 2 + protein on dipstick analysis, while on microscopy there were no cells and the specimen was sterile on culture, haemoglobin 107 g/l, plasma creatinine was confirmed at 0.44 ‘ ■■’;-■■■ •