UMEM Educational Pearls

Category: Critical Care

Title: Hyperammonemia in the Critically Ill

Keywords: hyperammonemia, hepatic failure, cerebral edema (PubMed Search)

Posted: 10/16/2007 by Mike Winters, MD (Updated: 12/7/2019)
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Hyperammonemia in the Critically Ill

  • Patients with acute hyperammonemia have significant morbidity and mortality 
  • Fulminant hepatic failure is the most common cause of acute hyperammonemia in adult ICUs
  • Other causes include TPN, GI hemorrhage, steroid use, trauma, multiple myeloma, infection with urease-splitting organisms, and drugs (salicylates, valproate) 
  • Cerebral edema, intracranial hypertension, seizures, and herniation are the most significant effects
  • Initial management should focus on treating intracranial hypertension - mannitol, hypothermia, N-acetylcysteine have been used
  • Lactulose has not been shown to reduce mortality in acute hyperammonemia but is unlikely to be harmful

Clay AS, Hainline BE. Hyperammonemia in the ICU. Chest 2007;132:1368-1378.