Steatohepatitis

Steatohepatitis is a form of fatty liver disease characterized by hepatic steatosis with inflammation and hepatocellular injury. It encompasses alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH). In ASH, chronic heavy alcohol use initiates liver injury that leads to fat accumulation, inflammation, and fibrosis. In NASH, steatosis occurs in people with metabolic risk factors such as obesity, type 2 diabetes, insulin resistance, and dyslipidemia; oxidative stress and inflammatory pathways contribute to hepatocyte injury and ballooning degeneration. The histologic hallmarks are macrovesicular steatosis, lobular inflammation, hepatocellular ballooning, and varying degrees of fibrosis; Mallory-Denk bodies may be present.

Most patients are asymptomatic; others may report fatigue, mild right upper quadrant discomfort, or hepatomegaly. Laboratory findings often show mildly elevated transaminases, with ALT sometimes predominating in NASH and a variable pattern in ASH.

Diagnosis relies on history, imaging, and laboratory tests. Imaging can detect fat in the liver, while liver biopsy remains the gold standard for distinguishing steatohepatitis from simple steatosis and for staging inflammation and fibrosis. Noninvasive scores and elastography can estimate fibrosis.

Management focuses on risk factor modification and avoidance of triggers. For ASH, abstinence from alcohol is essential; for NASH, weight loss through diet and physical activity, and control of diabetes and dyslipidemia, are central. No drugs are universally approved specifically for steatohepatitis; certain agents (for example, vitamin E or thiazolidinediones) may be considered in select patients, and several therapies are under investigation. Prognosis varies with the severity of fibrosis and the presence of cirrhosis.