Prevalence of non-alcoholic fatty liver disease in children High-calorie diet and lack of exercise make the incidence of obesity grow rapidly, as well as the acceptance of traditional concepts of childhood obesity, childhood obesity has become more and more popular, but the associated diseases brought about by it are a serious threat to children’s health, and non-alcoholic fatty liver disease (NAFLD) is an important cause of chronic liver disease in children. Epidemiologic investigations have found that the prevalence of NAFLD is 13%~14% in ordinary children, and obesity exists in about 90%. Taiwanese scholars used ultrasound to screen 216 children for NAFLD, and the prevalence was 16% in the normal weight group, 50.5% in the overweight group, and 63.3% in the obese group; compared with the normal population, there are significantly high body mass index and waist circumference in children with NAFLD. What are the symptoms and discomforts? Most children with NAFLD have no obvious signs and symptoms. A few can show generalized weakness, right upper abdominal discomfort, enlarged liver or even jaundice, ascites, edema, etc., but these symptoms can not be distinguished from other liver diseases. NAFLD has a family aggregation, and the parents of children with NAFLD have much higher chances of having NAFLD than those of children without NAFLD, so those who have a history of obesity, fatty liver, type 2 diabetes, cardiovascular disease are more likely to have a history of obesity, fatty liver, type 2 diabetes, and cardiovascular disease in the family. Therefore, people with a family history of obesity, fatty liver disease, type 2 diabetes, and cardiovascular disease should be more concerned about the presence or risk of NAFLD. Liver function tests may reveal elevated aminotransferases or even elevated bilirubin, decreased albumin/globulin ratios, or no abnormalities, but they lack specificity and are difficult to differentiate from other liver diseases. Pathologic examination Histologically, there is a big difference between childhood NASH and adult NASH. Ballooning, zone 3 fibrosis and inflammation of the liver parenchyma, which are common in adult NASH, are rarely seen in pediatric NASH. There are two typical pathological subtypes of NASH in children. type 1 NASH, which accounts for l7% of children, is histologically similar to that of adults and is characterized by steatosis with ballooning and intralobular inflammation, with or without perisinusoidal fibrosis, and without inflammation in the portal area. type 2 NASH, which accounts for 5l% of children, is the predominant histologic type, and is characterized by hepatic macrovesicular steatosis with concomitant inflammation in the portal area, with or without portal area fibrosis, and no or small amounts of ballooning. Type 2 NASH in children is more common in males and in younger age groups. The remaining 32% of children with NASH have features of both type 1 and type 2. Liver biopsy is currently the gold standard for the diagnosis of NASH and the only way to confirm the diagnosis. What are the non-invasive tests? Pathologic diagnosis is the gold standard, but most parents find it difficult to accept it, so ultrasound and CT are mandatory. ultrasound has high sensitivity for steatosis >30%, poor sensitivity for steatosis <30%, and the diagnosis of steatosis is compromised by the presence of fibrosis and steatosis at the same time. ultrasound is simple and non-invasive, but it is not quantitative and is only used for epidemiological screening. it is especially difficult to determine NASH. Liver stiffness measurement is a non-invasive test that has been gradually developed in recent years, which can determine the approximate proportion of hepatocytes and the degree of hepatic fibrosis, and according to our observation, the degree of consistency with pathological diagnosis is high, and experienced hepatologists can determine the status of NASH from the fat attenuation index and liver stiffness value. Case description Male, 13 years old, obese, with a family history of obesity, mild abnormalities in liver function ALT, etc., excluding hereditary diseases. Mild abnormalities, exclude genetic diseases, viral hepatitis possible. Pathological diagnosis of severe steatosis with periportal fibrosis in the confluent area, steatohepatitis type 2. Treatment plan for NAFLD in children 1, weight loss is the main non-invasive means of treatment of NAFLD in children, obesity is an important risk factor for NAFLD in children, especially central obesity, but the speed of weight loss should not be too fast, the goal of weight loss is negative calorie balance, generally negative 500-1000kcal calories per day for NAFLD in children. -1000kcal is reasonable for obese patients. Dietary control includes limiting carbohydrate and saturated fat intake (to within 10% of total calories), while dietary control must take into account the nutrients required for normal growth and development in children. Low-calorie diets (<500kcal/d) leading to rapid weight loss can exacerbate steatohepatitis in obese patients. Calorie supply should take into account the child's exercise level in addition to weight and growth factors. Moderate to heavy intensity physical activity (30 min/d, 3-5 times/week) can reduce complications in obese patients. However, it is not clear whether patients with NAFLD can achieve histologic improvement through physical activity alone. 2. Pharmacotherapy. Vitamin E is an antioxidant that may be effective in reducing oxidative stress. Open studies have found that vitamin E 400-1 200 U orally daily for 2-4 months resulted in improvement in serum ALT in obese children. Metformin is the only insulin sensitizing drug that has been studied in children with NAFLD. NAFLD is considered an important cause of chronic liver disease in children. NAFLD can be reversed and prevented with early detection and lifestyle interventions, while it quickly progresses to steatohepatitis and cirrhosis.Clinical diagnosis in children with NAFLD is mainly by ultrasound and biochemical tests, and normal transaminases in children with metabolic syndrome cannot exclude liver puncture. Liver tissue biopsy remains the gold standard for the diagnosis of NAFLD/NASH. There is a lack of evidence-based medicine for the treatment of NAFLD in children, but the successful experience of treating NASH in adults can be taken into account. Children are at a special stage of growth and development, and medication and surgery may not be conducive to weight loss. The consensus is to use dietary calorie control and exercise as the basis for weight loss, and family health education is also important.