Renal artery stenosis and nephrotic syndrome: a rare combination in an infant

Abstract

We describe an uncommon pediatric finding of unilateral renal artery stenosis, which presented as nephrotic syndrome, hypertension, failure to thrive, and hyponatremia. The child was a previously well 8-month-old male who looked well but had mild periorbital edema with severe hypertension. After 3 days of captopril therapy, the nephrotic-range proteinuria significantly improved. However, the hypertension persisted. Renal imaging revealed a small left kidney with reduced parenchymal uptake and no significant excretion. A renal angiogram demonstrated left renal artery stenosis with increased left renal vein renin activity. The hypertension resolved within 24 h of a left nephrectomy, but non-nephrotic-range proteinuria persisted for 8 months post operatively. Pathology of the left kidney was consistent with fibromuscular dysplasia. Although a few glomeruli (1%) had changes consistent with focal segmental glomerulosclerosis, such a few abnormal glomeruli were unlikely to account for the nephrotic syndrome. Hypertension-induced changes in the unaffected right kidney probably caused the nephrotic-range proteinuria.