Severe hyponatremia in a patient with renovascular hypertension: case report.

We report a 2-year-old boy with renovascular hypertension caused by stenosis of the left renal artery that was successfully treated by percutaneous transluminal angioplasty (PTA). He initially presented with severe hyponatremia, hypokalemia, polyuria, transient proteinuria and weight loss. This phenomenon is known to occur in patients with renovascular and malignant hypertension, called hyponatremia hypertensive syndrome, but was thought to be rare in children. Renovascular hypertension should be considered as a cause of hyponatremia in children. In addition, PTA is an appropriate treatment even in very young children with renovascular hypertension.