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Mannitol-induced acute renal failure
H R Dorman1, J H Sondheimer, P Cadnapaphornchai
1Department of Medicine, Wayne State University, School of Medicine, Detroit, Michigan.
Abstract:
Mannitol is widely used to reduce intracranial pressure and is protective against ischemic and nephrotoxic acute renal failure. However, the capacity of this seemingly innocuous agent to produce acute renal failure is not well recognized. We report herein the clinical course of 8 cases of mannitol-induced acute renal failure. In addition, we reviewed all previously reported cases of mannitol-induced renal failure. In the present series, acute oliguric renal failure developed within 3.5 +/- 1.1 (mean +/- SD) days after receiving daily and total mannitol doses of 189 +/- 64 g and 626 +/- 270 g, respectively, over 3.5 +/- 1.5 days. The peak serum creatinine was 5.7 +/- 2.7 mg/dl and peak osmolal gap was 74 +/- 39 mOsm/kg water. Renal tubular epithelial cells containing vacuoles were seen in the urinary sediments of 6 patients. Renal function improved rapidly upon discontinuation of mannitol and/or removal of mannitol by hemodialysis. In those previously reported cases in which the baseline renal function was normal, acute renal failure developed after receiving total mannitol doses of 1171 +/- 376 g. The peak osmolal gap was 107 +/- 17. In contrast, in those with underlying renal compromise, renal function worsened after a total mannitol dose of 295 +/- 143 g. The pathogenesis of mannitol-induced renal failure is not yet established but may be associated with renal vasoconstriction produced by high concentrations of mannitol. This may be averted in clinical practice by monitoring the osmolal gap, rather than serum osmolality alone, when using mannitol infusions for the treatment of intracranial hypertension.
Insights
Mannitol, often used to treat brain swelling, can paradoxically cause acute kidney injury. Monitoring the osmolal gap, not just serum osmolality, is crucial for safe mannitol use in patients.
Area of Science:
- Nephrology
- Pharmacology
- Critical Care Medicine
Background:
- Mannitol is a common osmotic diuretic used to reduce intracranial pressure and protect against certain types of acute kidney injury.
- However, its potential to induce acute renal failure is an underrecognized complication.
Purpose of the Study:
- To report on 8 new cases of mannitol-induced acute renal failure.
- To review previously documented cases to better understand the incidence, clinical course, and risk factors.
Main Methods:
- Case series analysis of 8 patients with mannitol-induced acute renal failure.
- Literature review of previously reported cases.
- Analysis of patient data including mannitol dosage, duration of treatment, serum creatinine, and osmolal gap.
Main Results:
- Acute oliguric renal failure developed within approximately 3.5 days of mannitol administration.
- Patients received average daily and total doses of 189g and 626g of mannitol, respectively.
- Peak serum creatinine reached 5.7 mg/dL with a peak osmolal gap of 74 mOsm/kg water; renal function improved after mannitol withdrawal or hemodialysis.
Conclusions:
- Mannitol can cause acute renal failure, particularly with higher cumulative doses or in patients with pre-existing renal compromise.
- Pathogenesis may involve renal vasoconstriction due to high mannitol concentrations.
- Monitoring the osmolal gap is recommended over serum osmolality alone for safer mannitol administration.