Acute hyperammonemic encephalopathy due to a portosystemic shunt in a non-cirrhotic adult patient.

Objective: To report a successfully treated hyperammonemia due to a portosystemic shunt in adult patient.

Data Source: A patient with an altered mental status due to severe elevated ammonia level because of a portosystemic shunt.

Conclusions: Hyperammonemia is not always related to liver failure in critically ill patients, but should be considered in all unknown origins of an altered mental status.