title: Pathophysiology of cerebral oedema in acute liver failure.
abstract: Cerebral oedema is a devastating consequence of acute liver failure (ALF) and may be associated with the development of intracranial hypertension and death. In ALF, some patients may develop cerebral oedema and increased intracranial pressure but progression to life-threatening intracranial hypertension is less frequent than previously described, complicating less than one third of cases who have proceeded to coma since the advent of improved clinical care. The rapid onset of encephalopathy may be dramatic with the development of asterixis, delirium, seizures and coma. Cytotoxic and vasogenic oedema mechanisms have been implicated with a preponderance of experimental data favouring a cytotoxic mechanism. Astrocyte swelling is the most consistent neuropathological finding in humans with ALF and ammonia plays a definitive role in the development of cytotoxic brain oedema. The mechanism(s) by which ammonia induces astrocyte swelling remains unclear but glutamine accumulation within astrocytes has led to the osmolyte hypothesis. Current evidence also supports an alternate 'Trojan horse' hypothesis, with glutamine as a carrier of ammonia into mitochondria, where its accumulation results in oxidative stress, energy failure and ultimately astrocyte swelling. Although a complete breakdown of the blood-brain barrier is not evident in human ALF, increased permeation to water and other small molecules such as ammonia has been demonstrated resulting from subtle alterations in the protein composition of paracellular tight junctions. At present, there is no fully efficacious therapy for cerebral oedema other than liver transplantation and this reflects our incomplete knowledge of the precise mechanisms underlying this process which remain largely unknown.
authors.affiliation: Teresa R Scott, Victoria T Kronsten, Robin D Hughes, Debbie L Shawcross, Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, London SE5 9RS, United Kingdom.
authors.forename: Teresa R
authors.initials: TR
authors.lastname: Scott
authors.affiliation: Teresa R Scott, Victoria T Kronsten, Robin D Hughes, Debbie L Shawcross, Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, London SE5 9RS, United Kingdom.
authors.forename: Victoria T
authors.initials: VT
authors.lastname: Kronsten
authors.affiliation: Teresa R Scott, Victoria T Kronsten, Robin D Hughes, Debbie L Shawcross, Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, London SE5 9RS, United Kingdom.
authors.forename: Robin D
authors.initials: RD
authors.lastname: Hughes
authors.affiliation: Teresa R Scott, Victoria T Kronsten, Robin D Hughes, Debbie L Shawcross, Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, London SE5 9RS, United Kingdom.
authors.forename: Debbie L
authors.initials: DL
authors.lastname: Shawcross
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000378:metabolism / Q000503:physiopathology; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D001929:Brain Edema / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D002199:Capillary Permeability; D018450:Disease Progression; D004734:Energy Metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006501:Hepatic Encephalopathy / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D017114:Liver Failure, Acute / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D018384:Oxidative Stress; D011379:Prognosis; D012307:Risk Factors
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D018698:Glutamic Acid; D000641:Ammonia
keywords: Acute liver failure; Ammonia; Cerebral blood flow; Cerebral oedema; Hepatic encephalopathy; Intracranial hypertension; Intracranial pressure