Where the Kidney is Concerned, How Much Mannitol is Too Much?

OBJECTIVE: To report a case of mannitol-induced acute renal failure (ARF). CASE SUMMARY: A 31-year-old woman who had been on long-term warfarin therapy for atrial fibrillation was admitted to the hospital with hemoptysis. Following reversal of her anticoagulation, she had a tonic-clonic seizure nine days after admission. An emergency computed tomography scan revealed cerebral edema, which was initially treated with hyperventilation and steroids. Two days later, a repeat scan showed progression of the cerebral edema with midline shift. Mannitol 550 g was infused over the next 28 hours, precipitating ARF. Despite prompt hemodialysis to reverse the renal failure, the patient died. This case of apparent mannitol-induced ARF illustrates several pathophysiologic effects of this agent. DISCUSSION: Case reports in the literature discussing mannitol-induced ARF are reviewed and compared. A relationship between dose and ARF and its reversal with hemodialysis is postulated. CONCLUSIONS: It is likely that sufficient doses of mannitol may lead to ARF. Limitation of dose may prevent and treatment with hemodialysis may reverse ARF in these instances.