Hepatic Encephalopathy (HE) is associated with abnormalities in brain metabolism of glucose, oxygen and amino acids. In patients with acute liver failure, cortical lactate to pyruvate ratio is increased, which is indicative of a compromised cerebral oxidative metabolism. In this meta-analysis we have reviewed the published data on cerebral blood flow and metabolic rates from clinical studies of patients with HE. We found that hepatic encephalopathy was associated with reduced cerebral metabolic rate of oxygen, glucose, and blood flow. One exemption was in HE type B (shunt/by-pass) were a tendency towards increased cerebral blood flow was seen. We speculate that HE is associated with a disturbed metabolism-cytopathic hypoxia-and that type specific differences of brain metabolism is due to differences in pathogenesis of HE.
Keywords: ALF, Acute Liver Failure; CBF, Cerebral Blood Flow; CMR, Cerebral Metabolic Rate; HE, Hepatic Encephalopathy; ICH, Intracranial Hypertension; MHE, Minimal Hepatic Encephalopathy; MRI, Magnetic Resonance Imaging; OHE, Overt Hepatic Encephalopathy; PCS, Portocaval Shunt; cerebral blood flow; cerebral metabolism; hepatic encephalopathy; liver failure; pcMRI, Phase-Contrast MRI.