title: Late-onset ornithine transcarbamylase deficiency: treatment and outcome of hyperammonemic crisis.
abstract: Hyperammonemic crises in ornithine transcarbamylase deficiency (OTC) can be associated with devastating cerebral edema resulting in severe long-term neurologic impairment and death. We present an 8-year-old boy who had late-onset OTC deficiency in which early and aggressive management of hyperammonemia and associated cerebral edema, including therapeutic hypothermia and barbiturate-induced coma, resulted in favorable neurologic outcome. Our patient presented with vomiting and altered mental status, and was found to have a significantly elevated serum ammonia level of 1561 μmol/L. Hyperammonemia was managed with hemodialysis, 10% sodium phenylacetate, 10% sodium benzoate, L-arginine, intravenous 10% dextrose, intralipids, and protein restriction. He developed significant cerebral edema with intracranial pressures >20 mm Hg, requiring treatment with 3% saline and mannitol. Despite this treatment our patient continued to have elevated intracranial pressures, which were treated aggressively with non-conventional modalities including therapeutic hypothermia, barbiturate-induced coma, and external ventricular drainage. This therapy resulted in stabilization of hyperammonemia and resolution of cerebral edema. Molecular testing later revealed a hemizygous mutation within the OTC gene. Neuropsychological testing 1 year after discharge showed normal intelligence with no visual-motor deficits, minor deficits in working memory and processing speed, and slightly below average processing speed and executive functioning.
authors.affiliation: Departments of Pediatrics and.
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Bergmann
authors.forename: James
authors.initials: J
authors.lastname: McCabe
authors.forename: T Ryan
authors.initials: TR
authors.lastname: Smith
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Guillaume
authors.forename: Kyriakie
authors.initials: K
authors.lastname: Sarafoglou
authors.forename: Sameer
authors.initials: S
authors.lastname: Gupta
mesh_terms: D017668:Age of Onset; D002648:Child; D006801:Humans; D022124:Hyperammonemia / Q000209:etiology*; D008297:Male; D020163:Ornithine Carbamoyltransferase Deficiency Disease / Q000150:complications* / Q000628:therapy*
keywords: barbiturates; cerebral edema; hyperammonemia; induced hypothermia; intracranial hypertension; ornithine transcarbamylase deficiency