Initial treatment of a neonate with MSUD requires a prompt reduction in the levels of the BCAAs. High levels of leucine are very toxic and can lead to brain injury resulting in mental retardation, neurological difficulties in walking and speech, seizures, or death. Dialysis is no longer the preferred method of reducing high levels of BCAAs. A much more effective treatment is the administration of intravenous (IV) solutions of amino acids that do not contain the BCAAs and which have glucose (a type of sugar) added for additional calories. Using IV solutions, developed specifically for this purpose, allows the excess leucine, valine and isoleucine to be utilized for protein synthesis in the body, thus rapidly decreasing the BCAA levels. Sometimes insulin or a similar agent is also given to speed up the utilization of the excess BCAAs. Adding additional isoleucine and valine helps prevent deficiencies of these two BCAAs since these levels drop more rapidly than leucine. Low levels of isoleucine can cause severe rashes on the infant and prevent anabolism.
Long-term treatment of MSUD involves a carefully controlled diet which strictly limits dietary protein in order to prevent the accumulation of BCAAs in the blood. The major component of the diet is a special formula designed for children with MSUD. These MSUD formulas do not contain any leucine, isoleucine or valine but are otherwise nutritionally complete. They contain all the necessary vitamins, minerals, calories and the other amino acids needed for growth.
Initially the infant will be given an MSUD formula supplemented with carefully controlled amounts of a protein-based formula such as Enfamil or Similac. The protein-based formula provides the infant with the limited amount of BCAAs needed to grow and develop normally. Frequent monitoring of blood levels and adjustments in the formula mixture are necessary to ensure the correct balance of leucine, isoleucine, and valine.
As children with MSUD grow, they continue taking the special formula. They are allowed other foods which are weighed or measured in the home to supply the prescribed amount of leucine each day. Typically the MSUD diet does not include any high protein foods such as meat, nuts, eggs, and most dairy products. Children gradually learn to accept the responsibility for controlling their diets. There is no age at which diet treatment can be stopped. Lifelong therapy is essential for an optimal outcome.
A liver transplant is an optional treatment. A donor liver from a person who does not have MSUD has enough enzyme activity to allow the person with MSUD to live free of the affects of MSUD. After transplant, the person with MSUD still carries the gene for MSUD which can be passed to their offspring. However, they are no longer in danger of a metabolic crisis and can eat a normal diet. The liver from the recipient is sometimes transplanted into another person needing a liver in a domino transplant.
|Last Updated on Monday, April 05 2010 12:12|