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.
