“Brain on Fire”: Hyperperfusion as a Hallmark of Hyperammonemic Encephalopathy

Abstract

AbstractWe describe a very rare case of acute fulminant hepatic failure as a complication of acute viral hepatitis caused by hepatitis A virus, complicated by hyperammonemic encephalopathy. The brain magnetic resonance imaging (MRI) findings were suggestive of cytotoxic edema involving bilateral cerebral hemispheres. The novel findings of hyperperfusion on arterial spin labeling perfusion MRI and hyperemic hypoxia on susceptibility weighted imaging are discussed. The patient had a rapid progression of cerebral edema and succumbed to the illness despite supportive care. Characteristic neuroimaging findings may help in the diagnosis of acute hyperammonemic encephalopathy of brain MRI, which may be useful in leading to appropriate clinical workup and diagnosis of the underlying cause of hyperammonemia. In our case, hyperammonemic encephalopathy was precipitated by fulminant hepatic failure caused by hepatitis A virus, which is a rare occurrence.