How are Urea Cycle Disorders Diagnosed and Treated?
Urea cycle disorders can be detected prenatally using tests such as amniocentesis and chorionic villi sampling. Postnatal diagnosis can be done through a variety of laboratory tests that are available.
Prenatal tests (tests done on the fetus in the uterus) such as chorionic villi sampling and amniocentesis can be carried out to identify deficiencies in the enzymes of the urea cycle at a early stage.
Urea cycle disorder can also be diagnosed following birth with the help of laboratory tests including plasma ammonia concentration, the anion gap, pH, CO2, quantitative analysis of plasma amino acids, and analysis of urine organic acids and urine orotic acid. Urea Cycle Enzyme assays can measure the activity of enzymes involved in the urea cycle.
Genetic testing can identify the specific gene mutation causing the UCD. This can be particularly helpful for diagnosis and genetic counseling.
A plasma ammonia level of 150 mmol/L or higher, along with a normal anion gap and normal serum glucose levels is strongly suggestive of UCD.
Main treatment strategies include -
- Reducing plasma ammonia levels and initiating alternative pathways for ammonia excretion through the administration of medications.
- Some medications are used to scavenge ammonia. These include sodium phenylacetate-sodium benzoate. Arginine and Citrulline administration is also done for most UCDs.
- Sometimes excess ammonia is removed by dialysis which is the quickest and most efficient method to remove ammonia from the body.
- Control in dietary nitrogen intake. This would include consuming less protein and instead consume more carbohydrates
- Reducing the risk of brain damage by ammonia using medications.
- Liver transplantation may be necessary in severe cases. Genetic counseling is also offered to these patients.
