Adult nonhepatic hyperammonemia: a case report and differential diagnosis

Am J Med. 2010 Oct;123(10):885-91. doi: 10.1016/j.amjmed.2010.02.029.


This article presents a case report of nonhepatic hyperammonemia, i.e., elevated serum ammonia secondary to a nonhepatic etiology. It then discusses the importance of broadening one's differential diagnosis to include such nonhepatic causes of elevated ammonia levels, and provides a short review of rarer causes of hyperammonemia in the adult population. Treating the underlying condition is the best way to prevent recurrence of hyperammonemia. However, symptomatic treatment should not be delayed while investigating the underlying source.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Ammonia / blood
  • Diagnosis, Differential
  • Humans
  • Hyperammonemia / chemically induced
  • Hyperammonemia / diagnosis*
  • Hyperammonemia / etiology
  • Liver Diseases / complications
  • Male
  • Metabolism, Inborn Errors / complications
  • Middle Aged
  • Urea / metabolism
  • Valproic Acid / adverse effects


  • Valproic Acid
  • Ammonia
  • Urea