Continuous venovenous hemofiltration rapidly lowers toxic metabolites in a patient with MSUD and imminent cerebral herniation.

Maple syrup urine disease (MSUD) is an inborn error of amino acid metabolism. During catabolic stress encephalopathy and brain swelling that can culminate in brain herniation may occur. Beyond the neonatal period, these metabolic decompensations normally can be treated with a conservative dietary emergency regimen. Nevertheless in exceptionally severe cases also older patients may require extracorporeal interventions. We present the case of a 12-year-old patient with cerebral edema and imminent cerebral herniation. Continuous venovenous hemofiltration (CVVH) caused a prompt decrease of the toxic metabolite levels as well as an improvement of the patient's condition.