OVERVIEW
Non-alcoholic steatohepatitis (NASH), also known as metabolic steatohepatitis, is a clinical syndrome with pathologic changes similar to those of alcoholic hepatitis but without a history of excessive alcohol consumption, and is more common in middle-aged, especially overweight and obese individuals. NASH is closely related to metabolic disorders such as obesity, insulin resistance, type 2 diabetes mellitus, hyperlipidemia, etc. It is mainly characterized by hepatocellular vesicular steatosis accompanied by hepatocellular damage and inflammation, and in severe cases, it may develop into cirrhosis, for which there is no specific treatment available.
Etiology
The cause of the disease is not clear. Patients usually have insulin resistance and related metabolic disorders, such as hypercholesterolemia and hypertriacylglyceridemia, as well as impaired regulation of glucose metabolism or diabetes mellitus. However, not all obese or diabetic patients suffer from NAFLD, and the possible factors are as follows.
1. Second Strike Theory
The first strike is insulin resistance to hepatocellular steatosis, and the second strike is mild liver injury factors through oxidative stress, lipid peroxidation damage to steatohepatitis.
2. Insulin resistance
Adipose hormones and adipokines released by adipose tissue, especially toxic inflammatory proteins, oxidative stress in hepatocytes.
Symptoms
Early symptoms of the disease are not obvious, the disease progresses slowly, and the disease can be reversed in some patients without special treatment. Deterioration of the disease may lead to scar tissue proliferation or liver fibrosis and progress to cirrhosis, which may be manifested by lack of appetite, fatigue, edema, muscle atrophy, gastrointestinal bleeding and liver failure.
Examination
1. Laboratory examination
Liver function tests show increased transaminases.
2. Imaging examination
Increased liver fat can be seen.
3.Liver biopsy
Hepatic steatosis combined with intralobular inflammation and ballooning can be seen.
4. Non-invasive liver stiffness elastography (FibroScan)
Helps to assess the severity of liver fibrosis.
Diagnosis
1. No history of alcohol consumption or a daily alcohol intake of <20 g of ethanol for women and <30 g for men.
2. Laboratory tests show elevated aminotransferases, and further tests should be performed to rule out drugs, viral hepatitis, and other factors of liver damage.
3. Increased hepatic fat can be seen on imaging, and non-alcoholic steatohepatitis should be considered.
4. Confirmation of diagnosis depends on liver biopsy.
Treatment
1. General treatment
Reducing the weight and waist circumference of overweight or obese people, balancing healthy diet, increasing physical activity, avoiding alcohol consumption, avoiding the application of unnecessary medicines and health care products can help to improve the liver enzymes and liver histological damage, and also beneficial to the prevention and treatment of hyperlipidemia, gout, diabetes mellitus, heart disease, etc. Those who have lost 7%-10% of their body weight within 1 year can improve liver function and reverse liver histological damage to different degrees.
2.Drug treatment
Vitamin E can significantly reduce the serum aminotransferase level of adults with NAFLD and improve the liver histologic damage.
3. Liver transplantation
Liver transplantation is the only life-saving measure for patients with progressive cirrhosis associated with liver failure.
Prognosis
Patients with nonalcoholic steatohepatitis have significantly higher rates of liver disease disability and mortality than those with simple steatohepatitis. Diabetes mellitus is an important indicator of poor prognosis in patients with NAFLD. The presence and degree of hepatic fibrosis is an independent predictor of death from liver disease in patients with nonalcoholic steatohepatitis. Age and degree of liver inflammation were independent predictors of progression of liver fibrosis in patients with nonalcoholic steatohepatitis.