Medical Care
As in all hyperammonemic states, immediately restrict dietary protein in patients with citrullinemia. Emphasize other nonprotein caloric sources to compensate.
Intravenous sodium benzoate, sodium phenylacetate, and arginine are important therapeutic avenues for reduction of blood ammonia levels. Intravenous benzoate and phenylacetate are investigational new drugs. In severe cases, hemodialysis may be indicated to rapidly reduce the blood ammonia level.
Long-term management requires close dietary monitoring and oral administration of sodium phenylbutyrate and arginine.
In every case, a biochemical geneticist should administer definitive short- and long-term treatment with sufficient laboratory backup to obtain rapid ammonia and amino acid levels.
Surgical Care
As is the case for the other members of the family of urea cycle disorders, liver transplantation can be performed. The procedure has been used in several cases with excellent results, [17] the most successful report being that of a partial orthoptic transplant from a sibling in an adult (type II) patient. [18]
Consultations
See the list below:
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Geneticist
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Metabolic disease specialist
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Dietitian
Diet
As in all hyperammonemic states, immediately restrict dietary protein in patients with citrullinemia.
Emphasize other nonprotein caloric sources to compensate.
Prevention
Prenatal diagnosis of citrullinemia is possible and is available at academic centers. Molecular diagnosis is possible, using amniocytes or chorionic villi.
Further Outpatient Care
Patients with citrullinemia must be under the ongoing care of a biochemical geneticist or metabolic disease specialist with expertise in the care of urea cycle disorders.
A trained nutritionist should monitor the low-protein diet, which is essential in treatment.
Frequent monitoring of growth and blood amino acid levels is imperative in order to make adjustments before essential amino acid levels fall below normal and the child becomes catabolic.
Under no circumstances should a primary care provider provide follow-up for a patient with citrullinemia without the frequent input of a specialist.
Transfer
Any infant or child noted to have hyperammonemia should be considered for transfer to a medical center for further evaluation.
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Urea cycle. Compounds that comprise the urea cycle are numbered sequentially, beginning with carbamyl phosphate. At the first step (1), the first waste nitrogen is incorporated into the cycle; also at this step, N-acetylglutamate exerts its regulatory control on the mediating enzyme, carbamyl phosphate synthetase (CPS). Compound 2 is citrulline, the product of condensation between carbamyl phosphate (1) and ornithine (8); the mediating enzyme is ornithine transcarbamylase. Compound 3 is aspartic acid, which is combined with citrulline to form argininosuccinic acid (4); the reaction is mediated by argininosuccinate (ASA) synthetase. Compound 5 is fumaric acid generated in the reaction that converts ASA to arginine (6), which is mediated by ASA lyase.
