Hepatic Encephalopathy and Nitrogen Metabolism

Hepatic encephalopathy is a major complication of liver cirrhosis and acute liver failure and represents an important issue of clinical and socioeconomic relevance. Hyperammonemic syndromes due to inborn errors of metabolism can also trigger encephalopathy. Much effort has been devoted during recent decades to understand the pathogenesis of hepatic encephalopathy, not only at the level of molecular and cell biology, but also at the neurophysiological and neuropsychological level. Considerable advances in the understanding of the syndrome and its relation to nitrogen metabolism have been achieved since the introduction and application of modern techniques of cell and molecular biology, neurophysiology and functional brain imaging, including magnetencephalography, positron emission tomography and functional magnetic resonance imaging and spectroscopy. In addition, novel approaches for diagnosis and treatment of hepatic encephalopathy have been developed in recent years and our understanding of the basic mechanisms of ammonia metabolism and inborn hyperammonaemic states has improved considerably. Although many questions are still open, recent scientific advances strengthen the view that hepatic encephalopathy is a consequence of disturbed astroglial hydration and glia–neuronal communication with pathologically altered oscillatory electrical coupling and processing in the brain. The most recent developments in research on hepatic encephalopathy, inborn hyperammonaemic syndromes and nitrogen metabolism, including clinical aspects, were presented by international acknowledged experts in this active research field at the 12th International Symposium on Hepatic Encephalopathy, which was held from June 1 to 4, 2005 in Solingen, Schloss Burg, Germany. This book comprehensively summarizes the most important novel issues on hepatic encephalopathy and nitrogen metabolism and is of interest not only for scientists in the field, but also for interested clinicians. This update of present knowledge will provide a platform for future research in the field of hepatic encephalopathy and nitrogen metabolism.