ACE inhibition can improve orthostatic proteinuria associated with nutcracker syndrome.

Left renal vein entrapment syndrome (nutcracker syndrome) was documented by magnetic resonance angiography (MRA) as a cause of orthostatic proteinuria in a 14-year-old girl female adolescent. Because of continuous proteinuria we performed a left renal biopsy which showed moderate mesangial hypercellularity. Her overt orthostatic proteinuria disappeared after a treatment of angiotensin-converting enzyme (ACE) inhibition. Nutcracker syndrome remains a rare but important cause of elevated protein excretion, which can induce mesangial changes and be improved by ACE inhibitor treatment.