Utility of hemodialysis in maple syrup urine disease.

Maple syrup urine disease (MSUD) is an inborn error of metabolism stemming from a deficiency in 2-ketoacid dehydrogenase and resulting in the systemic accumulation of branched chain amino acids (BCAAs). Affected children may suffer profound developmental and cognitive impairment from exposure to high levels of BCAA and their associated neurotoxic metabolites. Endogenous renal clearance of BCAA is limited and several therapeutic modalities including intensive nutritional regimens, exchange transfusions, peritoneal dialysis, and continuous hemofiltration have been utilized in neonates with MSUD, all of which have had varying success in reducing systemic BCAA levels. In this report, a symptomatic 7-day-old 3-kg neonate with MSUD underwent treatment with a combination of early hemodialysis and aggressive enteral feedings of a metabolically appropriate formula. This approach results in a 75% reduction of systemic toxin levels within 3 h. When compared to other reported modalities of therapy for symptomatic neonates with MSUD, this approach appears to be most efficacious. Moreover, by minimizing the amount of time that an affected neonate is exposed to neurotoxic levels of BCAAs, long-term developmental and cognitive capabilities may be preserved.