Maple Syrup Urine Disease Treatment & Management
- Author: Olaf A Bodamer, MD, PhD, FAAP, FACMG; Chief Editor: Luis O Rohena, MD more...
The 2 main aspects to the treatment of maple syrup urine disease (MSUD) are long-term management and the treatment of episodes of acute metabolic decompensation. The mainstay in the treatment of MSUD is dietary restriction of branched-chain amino acids.[15, 7, 14]
Aggressively treat episodes of metabolic decompensation. Initiate intravenous glucose infusions (5-8 mg/kg/min for infants) as rapidly as possible. Insulin infusions may be added to promote anabolism. Stop intake of branched-chain amino acids but resume intake as soon as plasma branched-chain amino acids normalize. Whenever possible, continue additional dietary support, including lipids and/or formulas free of branched-chain amino acid. In rare circumstances, hemodialysis or peritoneal dialysis is required to remove branched-chain amino acids and keto acids.
Initial studies using retroviral vectors to infect MSUD lymphocytes have shown stable correction of the enzyme deficiency. However, human gene therapy trials for MSUD remain to be performed.
Several successful pregnancies in patients with MSUD have been reported. The most critical period seems to be the immediate postpartum period. Take particular care to counteract catabolism during this time.
Three successful liver transplantations in patients with classic MSUD have been reported. Children in a different study realized a high rate of patient and graft survival with normal liver function in all patients. The patients who were mentally impaired before transplantation realized no change in neurocognitive function 1 year later. These results suggest that liver transplantation may be an effective treatment for classic MSUD; while it may arrest brain damage, it will not reverse it. However, consider the risks and potential long-term complications of liver transplantation in contrast to the beneficial low-risk dietary therapy that has equally good outcome.
Orthotopic liver transplantation performed at an experienced center has changed the outlook for patients with classic MSUD, who are frequently challenged with frequent episodes of metabolic decompensation. While liver transplantation is not able to reverse neurological damage that has already occurred, it can prevent additional episodes of decompensation and preserve neurological function. If performed early in the disease course, liver transplantation may guarantee normal or near-normal neurological outcomes.
The goal of dietary therapy is normalization of branched-chain amino acids (particularly of leucine) by restricting intake of branched-chain amino acids without impairing growth and intellectual development. Dietary therapy must be lifelong. Several commercially available formulas and foods are available without branched-chain amino acids or with reduced levels of branched-chain amino acids.
Products are available for juveniles and adults, such as MSUD Express. The intake of leucine is calculated on an individual basis following the measurement of plasma branched-chain amino acids. Measure plasma amino acid levels on a regular basis at appropriate intervals for the first 6-12 months of life. In addition to dietary therapy, administer thiamine (10-20 mg/d) for 4 weeks to determine thiamine responsiveness.
Do not restrict activity.
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