Hepatic encephalopathy

The presence of hepatic encephalopathy, whether it occurs in patients with acute or chronic liver injury, indicates liver failure and is a serious complication. The pathogenesis of hepatic encephalopathy remains elusive, but the importance of ammonia, the glutamine–glutamate cycle, the involvement of other putative humoral factors and receptors as well as the importance of astrocytes are described. Patients with hepatic encephalopathy may present with a wide variety of clinical features ranging from easily overlooked mild cognitive impairment to coma with cerebral oedema. Although essentially a clinical diagnosis supportive data may be obtained from a variety of diagnostic tools and these are described. In the management of patients with hepatic encephalopathy the importance of removal of precipitants such as infection, reduction in dietary nitrogen load using agents such non-digestible disaccharides, is described, as is the management of hepatic encephalopathy in patients with fulminant hepatic failure. Finally, the importance of recognizing encephalopathy as a sign of liver failure is discussed and its presence should trigger the consideration of liver transplantation, where appropriate.