Acute Hepatic Encephalopathy Presenting as Cortical Laminar Necrosis: Case Report
A 55-year-old man was admitted to the emergency room with generalized tonic-clonic seizures and stuporous mentality, without regaining consciousness for two hours. He was a chronic alcoholic with alcoholic liver cirrhosis. The initial blood ammonia level was 1002 µmol/L (normal range 12-47 µmol/L), and the liver function test results were mildly deranged (bilirubin, 0.91 mg/dL; aspartate aminotransferase, 63 IU/L; alanine aminotransferase, 30 IU/L; pulmonary trunks 1.30 international normalized ratio). Other serum electrolytes and blood glucose levels were within normal ranges (glucose, 113 mg/dL). Anticonvulsant was initially administered intravenously, and the seizures immediately disappeared. Lactulose enema was administered to decrease the patient's blood ammonia level. Electroencephalography performed 3 days after the onset of symptoms showed continuous generalized slowing without epileptiform discharges, suggesting a moderate diffuse of cerebral dysfunction. No hypotensive or hypoxemic episode was observed during the admission days.\nDiffusion-weighted imaging (DWI) (b = 1000), 5 hours after the onset of seizures, showed relatively symmetric bilateral high signals in both temporo-fronto-parietal cortex, including insular and cingulate cortex, with restricted diffusion on the apparent diffusion coefficient (ADC) map (). The initial differential diagnosis was acute hepatic encephalopathy, hypoxic ischemic change, and other metabolic encephalopathy.\nOn the fourth day, MRI was performed at 3.0 tesla (Achieva; Philips Medical Systems, Best, the Netherlands), with T2-weighted (TR, 3000 ms; TE, 80 ms), fluid-attenuated inversion recovery images (FLAIR) (TR, 11000 ms; TE, 125 ms; TI, 2800 ms), and T1-weighted inversion recovery (TR, 2000 ms; TE, 10 ms) and intravenous contrast-enhanced images. An interval increase in the extent of brain cortical edema was noted in both cerebral hemispheres, while the occipital cortex and perirolandic regions were uniquely spared. Symmetric high signals were observed in both the medial thalami, basal ganglia, periventricular and cerebellar white matter on the T2-weighted and FLAIR images. Basal ganglia showed subtle high signal on the T1-weighted image in both globus pallidus (). No pathologic contrast enhancement was seen.\nAfter one month of medical treatment and supportive care, the patient's blood ammonia level decreased to 49 µmol/L, and his seizure attack did not recur. But the patient's intellectual function was impaired. Follow up brain MRI revealed a diffused cortical atrophy in both temporo-fronto-parietal lobe and curvilinear, gyriform high signals on the T1-weighted image in both temporal cortex. In addition, bilateral basal ganglia showed obvious high signals on the T1-weighted image (). These findings were considered as a cortical laminar necrosis, presumably, the consequence of extreme toxic effect of ammonia.