Snapshot A 30-year-old man presents to his primary care physician for intermittent generalized abdominal pain. He has a history of diabetes, hyperlipidemia, and obesity. He denies drinking alcohol regularly and has not taken any new medications. Laboratory evaluation reveals elevated liver enzymes and negative viral hepatitis serologies. A hepatic ultrasound shows increased echogenicity of the liver, suggestive of steatohepatitis. Introduction Overview nonalcoholic fatty liver disease (NAFLD) is characterized by fatty changes in the liver in patients without a history of alcoholism this may lead to inflammation and lobular hepatitis or nonalcoholic steatohepatitis (NASH) causes chronic hepatitis Epidemiology incidence common demographics can affect adults and adolescents risk factors obesity hyperlipidemia hypertriglyceridemia diabetes or insulin resistance Pathogenesis mechanism high levels of lipids or triglycerides, insulin resistance, and increased body weight cause fat to accumulate within the hepatic cells, resulting in decreased rate of metabolizing and excreting fat this results in inflammation and eventually fibrosis of the liver Presentation Symptoms often asymptomatic common symptoms vague abdominal discomfort Physical exam inspection hepatomegaly Imaging Ultrasound of the liver indications all patients findings steatohepatitis increased echogenicity coarsened echotexture of the liver cirrhosis nodular surface Studies Serum labs liver function panel elevated AST and ALT elevated alkaline phosphatase viral hepatitis panel to exclude viral cause of chronic hepatitis Invasive studies liver biopsy findings macrovesicular steatosis lobular inflammation with lymphocytes and Kupffer cells ballooned hepatocytes (liver damage) pericellular/perivenular or “chicken-wire” fibrosis Differential Autoimmune hepatitis key distinguishing factors autoimmune hepatitis presents with flares of jaundice, abdominal pain, pruritus, and may progress to encephalopathy positive anti-smooth muscle antibodies Treatment Lifestyle weight loss alcohol cessation good control of diabetes low-fat diet and good control of dyslipidemia Complications NASH-associated cirrhosis Hepatocellular carcinoma