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Emergency: requires immediate attention
Maple syrup urine disease
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Emergency: requires immediate attention

Maple syrup urine disease

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Other Resources UpToDate PubMed

Synopsis

Maple syrup urine disease (MSUD) is a rare inherited metabolic disorder characterized by a deficiency of the branched-chain alpha-keto acid dehydrogenase complex, causing an inability of the body to properly break down amino acids. There are 5 subtypes of MSUD including the most common classic form, second most common intermittent form, intermediate form, thiamine-responsive form, and E3 deficient form. Diagnosis can be made by measuring plasma amino acid concentrations. In newborns with the classic form, MSUD can be detected by screening with tandem mass spectrometry.

Classic MSUD symptoms can present within 48 hours following birth and include sweet-smelling urine that resembles maple syrup, poor feeding, irritability, vomiting, lethargy, dystonia, and apnea. Without treatment, the disease can cause neurological damage or death following central respiratory failure. Treatment during acute episodes of metabolic crisis is aggressive and supportive. Long-term management involves limiting the consumption of branched-chain amino acids and lifelong dietary restrictions. Prognosis can be normal with early intervention and prompt treatment of episodes.

The second most common subtype is intermittent MSUD, which does not present in infancy. Patients have normal intellectual development and growth and only experience symptoms in childhood and beyond following any catabolic stress such as infection, fever, dehydration, etc. The presentation of intermittent MSUD following catabolic stress includes ketoacidosis, anorexia, nausea, vomiting, fatigue, and signs of neurotoxicity including ataxia, cognitive impairment, hallucinations, sleep disturbance, dystonia, and seizures or coma. Treatment and management are similar to classic MSUD treatment and involve prompt and aggressive intervention during acute episodes and long-term dietary restriction of branched-chain amino acids.

Codes

ICD10CM:
E71.0 – Maple-syrup-urine disease

SNOMEDCT:
27718001 – Maple syrup urine disease

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Last Updated: 03/23/2016
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Emergency: requires immediate attention
Maple syrup urine disease
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Maple syrup urine disease (Classic MSUD) : Vomiting, Dystonia, Irritability, Lethargy, Poor feeding
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