Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Key Features ++ Typical presentation is infantile encephalopathy; later onset presentations are common with cyclic vomiting or encephalopathy with illness or protein load Diagnosis is suspected with the finding of hyperammonemia frequently with minimal other laboratory findings +++ Clinical Findings ++ Patients with severe defects usually present in infancy with severe hyperammonemia, vomiting, and encephalopathy, which is rapidly fatal Patients with milder genetic defects may present with vomiting, encephalopathy, or liver failure after increased protein ingestion or infection +++ Diagnosis ++ Blood ammonia should be measured in any acutely ill newborn in whom a cause is not obvious Early hyperammonemia is associated with hyperventilation and respiratory alkalosis Prenatal diagnosis is most commonly done by molecular methods +++ Treatment ++ During treatment of acute hyperammonemic crisis, protein intake should be stopped, and glucose and lipids should be given to reduce endogenous protein breakdown from catabolism Long-term treatment includes Low-protein diet Oral administration of arginine or citrulline Sodium benzoate or sodium phenylbutyrate (a prodrug of sodium phenylacetate) Hemodialysis or hemofiltration is indicated for severe or persistent hyperammonemia Liver transplantation May be curative Indicated for patients with severe disorders Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth