ABSTRACT
Effective management requires a precise diagnosis, but vigorous therapy should be initiated immediately on recognition of the hyperammonemia. Hyperammonemia may also be seen in acute exacerbation of disorders of fatty acid oxidation. A number of patients with various urea cycle disorders have received partial or total orthotopic liver transplants to provide enzyme replacement or somatic gene therapy, respectively. Chronic management of patients with urea cycle defects has also been effective using mixtures of the keto and hydroxy-acid analogs of essential amino acids. The central function of the urea cycle is the irreversible detoxification of ammonia to urea. Estimates based on multicenter studies and data from newborn screening indicate prevalences for all urea cycle disorders to be 1:35,000 newborns with large variation among single diseases in the USA. Symptomatic hyperammonemia may also result from a urinary tract infection in which the infecting Proteus mirabilis has urease activity, which produces ammonia from urea.
