Hepatic Encephalopathy Mimicking Acute Dominant Middle Cerebral Artery Ischemic Stroke: A Case Report.

Hepatic encephalopathy and hyperammonemia are common in the setting of liver disease and have been associated with both generalized and focal neurological deficits. We report a case of hepatic encephalopathy with transaminitis in the setting of hyperammonemia clinically mimicking acute dominant middle cerebral artery (MCA) syndrome. A 59-year-old right-handed woman had new-onset expressive aphasia, left gaze deviation, and right hemiparesis consistent with MCA stroke. Her symptoms began 12 h after transarterial chemoembolization, a procedure to embolize blood supply and provide cytotoxic agents to a hepatocellular carcinoma tumor. Thrombocytopenia and age-indeterminate hypodensities on brain CT precluded intravenous thrombolytic administration. MRI revealed predominantly dominant hemisphere subcortical restricted diffusion with no cortical involvement. Due to a mismatch between the MRI findings and the neurological symptoms, she underwent digital subtraction cerebral angiography to assess candidacy for intra-arterial thrombectomy, which revealed completely patent MCAs with intact filling of the distal branches. Liver enzymes and ammonia were elevated. The patient was treated with lactulose and intravenous fluids. After normalization of liver enzymes, the patient's neurological deficits resolved. Reversal of this patient's focal symptoms with medical management could potentially be explained by the recovery of blood flow-metabolic demand mismatch caused by worsening liver dysfunction and hyperammonemia. As acute stroke therapies and interventions increase in utility for large artery acute ischemic stroke, it is vital to recognize hepatic encephalopathy and liver failure as part of the differential diagnosis for patients presenting with MCA syndrome.