Mannitol-induced acute renal failure

Mannitol is widely used because of its osmotic diuretic action and its presumed antioxidant properties. In pre-existent renal dysfunction, however, mannitol may accumulate leading to potentially deleterious effects. We describe a 71-year-old woman with moderate chronic renal failure due to diabetic nephropathy who developed acute anuric renal failure after mannitol administration for post-traumatic reflex sympathetic dystrophy. After haemodialysis symptoms of acute renal failure rapidly disappeared with recovery of pre-existent renal function. Daily measurement of the osmolal gap as a simple and accurate way of monitoring patients receiving mannitol infusion is emphasized. A rapid increase in the osmolar gap should prompt adjustment of the dose or even discontinuation of mannitol, especially in the case of pre-existent risk factors.