ENLmedical.com: Conditions And Concerns: Medical Encyclopedia: Maple syrup urine disease

Maple syrup urine disease

Causes and Risks:
Maple syrup urine disease (MSUD) is caused by the inability to metabolize the amino acids leucine, isoleucine, and valine. The disease is so named because urine from affected people smells like maple syrup.

In the most severe form, MSUD causes severe acidosis during the first week of life. This is characterized by progressively poorer feeding, vomiting , seizures , lethargy , and finally coma . Untreated infants die in the first few weeks of life. MSUD also occurs in an intermittent form and a mild form. Even the mildest form, MSUD results in retardation and bouts of acidosis precipitated by stresses such as illness.

Prevention:
Genetic counseling is suggested for prospective parents with a family history of maple syrup urine disease.

Symptoms:

family history of MSUD
urine which smells like maple syrup
feeding difficulties
lethargy
vomiting
seizures
coma

Signs and Tests:

urine amino acids (elevated levels of the amino acids leucine, isoleucine, and valine)
plasma amino acids (elevated levels of leucine, isoleucine, and valine)

Treatment:
Treatment of the acute episode:

Acute acidosis is treated to restore normal pH.
Peritoneal dialysis can be used to remove the high levels of amino acids .

Long range treatment:
Treatment includes a special diet. Strict compliance is necessary to prevent neurological damage. This requires close supervision by a registered dietitian or physician, and cooperation by parent(s). The diet includes a synthetic infant formula without the amino acids leucine, isoleucine, and valine. Affected people must remain on this diet permanently.

Prognosis:
If left untreated, life-threatening neurological damage may result. Despite dietary treatment, stressful situations can still precipitate bouts of acidosis and death may occur during these episodes.

Complications:

neurological damage
acidosis episodes (may be fatal)

Call Your Healthcare Provider:
Call your health care provider if you have a family history of MSUD and are contemplating starting a family. Also call if you have a newborn who exhibits symptoms suggestive of maple syrup urine disease.