Acute renal failure following massive mannitol infusion and enalapril treatment

We report a patient with reversible acute oligoanuric renal failure. Intravenous mannitol 25% was infused to treat intracranial edema, during chronic administration of ACE inhibitors for arterial hypertension. Serum creatinine level rose to 5.6 mg/dl from a previous value of 1.2 mg/dl. Measured and calculated serum osmolalities were 310 and 280 mosm/kg respectively. We postulate that the association of afferent arteriolar constriction due to mannitol induced tubulo-glomerular imbalance and efferent dilatation due to ACE inhibitors provoked a sharp reduction in glomerular filtration rate. Alternatively, mannitol infusion may have caused tubular cell swelling with luminal obstruction.