NONALCOHOLIC STEATOHEPATITIS

Objective: To determine the clinical relevance of nonalcoholic steatoh epatitis (NASH) and to review the available literature on the epidemio logy, clinical features, histology, pathogenesis, clinical course, and management of this condition. Data Sources: Pertinent articles in Eng lish identified through a MEDLINE search (1966 to the present) and the bibliographies of relevant articles. Study Selection: All studies, in cluding case reports, evaluating the salient features and clinical pro file of NASH. Data Extraction: Data were selected from all articles th at fit the study selection criteria. Data Synthesis: Nonalcoholic stea tohepatitis is a distinct clinical entity characterized by elevated pl asma liver enzyme levels and liver biopsy findings that are identical to those seen in alcoholic hepatitis; patients with NASH, however, do not consume alcohol in quantities known to cause liver injury. Patient s with NASH are typically obese, middle-aged women with asymptomatic h epatomegaly who are diabetic or hyperlipidemic and present with an unr elated medical problem. Analysis of liver biopsy specimens is the corn erstone of diagnosis; hepatic morphologic findings range from mild fat ty degeneration and inflammation to cell degeneration, fibrosis, and c irrhosis with or without the presence of Mallory hyaline bodies. Eleva ted levels of free fatty acids in the liver are thought to be responsi ble for the development of steatohepatitis. Although NASH is most ofte n a benign disease with an indolent course, patients with this conditi on occasionally develop cirrhosis, portal hypertension, and hepatic fa ilure. In some cases, NASH may be reversed with weight reduction. Conc lusion: Nonalcoholic steatohepatitis is an important differential diag nosis for asymptomatic patients with chronically elevated plasma liver enzyme levels, especially if obesity, diabetes, or hyperlipidemia are present. Analysis of liver biopsy specimens is necessary for diagnosi s and must be done in all patients with unexplained abnormal liver fun ction and negative results on a noninvasive workup. Prognosis is good in most patients. The precise role of weight reduction and ursodeoxych olic acid therapy in the favorable alteration of the natural history o f this disorder needs to be addressed in large, well-controlled studie s.