Nonalcoholic Steatohepatitis (NASH)

Excerpt

Nonalcoholic, fatty liver disease (NAFLD) is defined as the ectopic accumulation of fat in the liver (hepatic steatosis) when no other causes of secondary liver fat accumulation are present. Although, minor deposition of fat can occur in the liver of healthy adults, deposition of fat in at least 5% of hepatocytes is considered pathologic. NAFLD includes both nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH) which is diagnosed when there is evidence of inflammatory activity and hepatocyte injury in a steatotic liver tissue. The diagnosis of NAFLD should not be made in a patient who has a history of significant alcohol consumption. The acceptable level of daily alcohol consumption is considered to be less than 20 g/day in men and 10 g/day in women. These cutoff values are not accurately defined, especially in patients with prior history of heavy alcohol use and those who are prone to NASH. NASH can progress to liver fibrosis, cirrhosis, and hepatocellular carcinoma with about 30% to 40% of patients developing fibrosis. NASH is not a diagnosis of exclusion and can be associated with other liver conditions such as chronic hepatitis C. NASH is classified into two types, primary; which is related to obesity and diabetes in the absence of excessive alcohol intake, and secondary; which is toxin or drug induced. This article will focus on primary NASH.