The following information may help to address your question:
The treatment of citrullinemia type I should be monitored by a metabolic diseases specialist and/or a dietician. Prompt treatment is necessary to prevent the build-up of ammonia, so treatment should be initiated as soon as the diagnosis is made. Mainstays of treatment include:
Long-term management includes blood tests to monitor blood levels of ammonia and amino acids which can help to make adjustments to diet and medical treatments. A physician should be contacted immediately in case of any illness.
With prompt and lifelong treatment, children with citrullinemia type I can often live healthy lives with typical growth and learning. Early treatment can help prevent high ammonia levels. However, even with treatment, some children may still have episodes of high ammonia. This can result in brain damage which can cause lifelong learning problems, mental retardation or spasticity. Individuals often have cognitive impairment. Children with the severe form (plasma ammonia levels greater than 480 µmol/L [or an initial plasma ammonia concentration greater than 300 µmol/L] who are treated promptly may survive for an indeterminate period of time, but usually have significant neurologic deficits.