Nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is excessive fat build-up in the liver due to causes other than alcohol use. There are two types non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Non-alcoholic fatty liver usually does not progress to liver damage or NASH. NASH includes both a fatty liver and liver inflammation. It may lead to complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease. Non-alcoholic fatty liver disease (NAFLD) is excessive fat build-up in the liver due to causes other than alcohol use. There are two types non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Non-alcoholic fatty liver usually does not progress to liver damage or NASH. NASH includes both a fatty liver and liver inflammation. It may lead to complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease. Risk factors include diabetes, obesity, a diet high in fructose and older age. NAFLD and alcoholic liver disease are types of fatty liver disease. NAFLD is related to insulin resistance and metabolic syndrome. It can be diagnosed by a liver biopsy. Treatment is generally with weight loss by dietary changes and exercise. There is tentative evidence for pioglitazone and vitamin E. Those with NASH have a 2.6% risk of dying per year. NAFLD is the most common liver disorder in developed countries, affecting 75 to 100 millions Americans in 2017. Up to 80% of obese and up to 20% normal-weight people might develop it. It is estimated that 24% of the worldwide population is affected in 2017. NAFLD is the leading cause of chronic liver disease as of 2017. About 12 to 25% of people in the United States have NAFLD, while NASH affects between 2 and 12%. The annual economic burden was estimated at US$103 billion in the US in 2016. NAFLD is evidence of hepatic steatosis, and absence of another factor that could explain the fat accumulation in the liver, such as alcohol (over 21 standard drinks/week for men and 14 for women), drug-induced steatosis, heredity or by deficiencies in parenteral nutrition such as choline. Excessive alcohol use (over 30 g daily for men and 20 g for women), drug-induced steatosis, hepatitis C and endocrine conditions are alternative causes of fatty liver unrelated to NAFLD. The NAFLD can be separated into two histological categories: NAFL, and the more aggressive form NASH. According to AASLD, both NAFL and NASH are defined by the presence of at least 5% of hepatic steatosis, but for NAFL there should be no evidence of 'hepatocellular injury in the form of hepatocyte ballooning,' whereas NASH is characterized by the presence of inflammation with hepatocyte injury such as ballooning, with or without any fibrosis. People with NAFLD are likely to be asymptomatic − to have no noticeable symptoms − and often have normal laboratory profiles. NAFLD can cause symptoms related to liver dysfunction. NAFLD can be diagnosed by performing a liver biopsy, and is often incidentally diagnosed following abnormal liver function tests during routine blood tests or after a hepatic steatosis is detected by biopsy. Indeed, in cases of symptoms or signs attributable to liver disease or when tests show abnormal liver chemistries, NAFLD should be suspected and investigated. However, when no symptoms or signs attributable to liver disease are reported or when the tests show normal liver chemistries, but a hepatic steatosis is detected, other metabolic risk factors (e.g., obesity, diabetes mellitus, dyslipidemia) and alternate causes such as alcohol should be investigated. Patients may complain of fatigue, malaise, and dull right-upper-quadrant abdominal discomfort. Mild jaundice may be noticed, although this is rare.