Unexplained hyperammonemia in the emergency department: Late-onset ornithine transcarbamylase deficiency in a 75-year-old man.
Jae Hyuk Lee, Sungbae Moon, Haewon Jung et al.
✦ AI-curated · Sources linked
Case in brief
A 75-year-old man presented to the emergency department with acute confusion and vomiting, which progressed to coma. Initial tests showed unexplained hyperammonemia, peaking at 487 μmol/L. Despite an initial lactulose enema, his condition worsened, necessitating endotracheal intubation and emergent hemodialysis. Genetic testing confirmed late-onset ornithine transcarbamylase deficiency. He was managed successfully and discharged without neurological sequelae.
What made this case unusual
This case illustrates late-onset ornithine transcarbamylase deficiency in a geriatric patient, a rare presentation of an X-linked urea cycle disorder.
Diagnostic / clinical pearl
Clinicians should consider urea cycle disorders in the differential diagnosis of unexplained hyperammonemia, even in older patients.
Why it matters
The case emphasizes the importance of thorough family history and timely hemodialysis to prevent neurological damage in atypical presentations.