精品论文严重肝病引起的以代谢紊乱为基础的神经课件.ppt

Hepatic Encephalopathy Definition (1) Hepatic encephalopathy (HE) It represents a reversible decrease in neurological function, based upon the disorder of metabolism which is caused by severe decompensated liver disease . 严重肝病引起的以代谢紊乱为基础的神经、精神综合征。主要临床表现为意识障碍、行为失常和昏迷 Definition (2) Subclinical or latent HE diagnosed only by precise mental tests or EEG, no obvious clinical and biochemical abnormalities Incidence/prevalence Universal feature of acute liver failure 50%~70% in chronic hepatic failure Difficult to estimate Etiology Fulminant hepatic failure acute severe viral hepatitis, drug/toxin, acute fatty liver of pregnancy Due to acute hepatocellular necrosis Chronic liver disease cirrhosis of all types , surgically induced portal-systemic shunts, primary liver cancer Due to one or more potentially reversible precipitating factors Common precipitating factor Deterioration in hepatic function Drugs Sedatives potentially hepatotoxic agents Gastrointestinal bleeding Excessive dietary protein Uremia/azotemia Infection Constipation Anesthesia and surgery Hypoxia Diuretics hypokalemia, Alkalosis hypovolemia Pathogenesis (1) Toxic materials derived from nitrogeneous substrate in the gut and bypass the liver HE is caused by several factors act synergistically Several putative gut-derived toxins identified Pathogenesis (2) Postulated factors/mechanisms: Ammonnia neurotoxicity Synergistic neurotoxins Excitatory inhibitory neurotransmitters and plasma amino acid imbalance hypothesis γ-Aminobutyric acid（GABA）/BZ hypothesis Ammonia neurotoxicity Over production and/or hypoeccrisis Poor hepato-cellular function:incomplete metabolism Portal-systemic encephalopathy: bypass Ammonia intoxication Interfere with cerebral metabolism: Depletion of glutamic acid, aspartic acid and ATP Depression cerebral blood flow and oxygen consumption Ammonia neurotoxicity El