Fulminant liver failure is a syndrome of massive production of hepatocellular necrosis and severe hepatic impairment caused by multiple etiologies, with no previous history of liver disease and the onset of hepatic encephalopathy within 8 weeks of the disease. It has an acute onset, rapid progression and high mortality rate. Early diagnosis and treatment can reduce the mortality rate. Differential diagnosis of progressive liver shrinkage: 1. Psychosis Hepatic encephalopathy with psychiatric symptoms as the only prominent manifestation is easily misdiagnosed as psychosis. Therefore, patients with mental confusion of unknown origin should be alerted to the possibility of hepatic encephalopathy. 2, metabolic encephalopathy such as diabetic ketoacidosis, hypoglycemia, uremia, hypernatremia, hyponatremia, etc. According to the history of the corresponding underlying disease, combined with relevant laboratory tests and blood gas analysis can help identify. 3, cranial lesions Various cerebrovascular accidents (cerebral hemorrhage, cerebral infarction, subdural hemorrhage), intracranial tumors, brain abscess, encephalitis, meningitis, etc. can appear coma and lethargy. According to the neurological symptoms and signs, combined with cranial CT or MR examination, and cerebrospinal fluid examination, most of them can be clearly diagnosed. 4.Toxic encephalopathy Encephalopathy caused by alcoholism, drug poisoning, heavy metal poisoning, based on the history of alcoholism, drug use and special occupational exposure, combined with laboratory tests, can help the differential diagnosis. Particular attention is paid to the differentiation from alcohol-related diseases, such as acute alcoholism and withdrawal syndrome that occurs after withdrawal is similar to the manifestation of HE. The key to differentiation is the history of alcohol consumption, elevated blood alcohol concentration, and more significant bradycardia, fever, and tremor when withdrawing from alcohol.