【Overview】 Dyslipidernia in children and adolescents is a disorder of plasma lipid metabolism in children and adolescents, which is mainly manifested as hyperlipidemia, including elevated plasma total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C), and decreased high-density lipoprotein-cholesterol (HDL-C). Dyslipidemia in children and adolescents not only leads to metabolic syndrome, fatty liver, pancreatitis, lipid nephropathy, etc., but is also closely related to atherosclerosis (AS) in adults, which is an independent risk factor for cardiovascular disease in adults. Dyslipidemia in children and adolescents is not rare, and its incidence rate has reached 15% to 20% in individual developed countries, and about 10% in China. 2006 epidemiological survey in Beijing showed that the incidence rate of hyperlipidemia in children and adolescents (6-18 years old) was 9.8%, of which the incidence rate in urban areas was 10.55% (10.16% in boys and 10.94% in girls), and the incidence rate in suburbs was 8.62% (6.6% in boys and 10.94% in girls). The prevalence rate in urban areas was 10.55% (10.16% for boys and 10.94% for girls) and in suburban areas was 8.62% (6.11% for boys and 11.18% for girls). The etiology of dyslipidemia in children and adolescents can be divided into two categories: primary and secondary. The etiology of primary dyslipidemia is still unclear, and there are currently two speculations: ① genetic factors, accounting for the vast majority of pediatric hyperlipidemia. Genetic factors account for the vast majority of pediatric hyperlipidemia. Congenital genetic defects cause abnormalities in receptors, enzymes, or apolipoproteins involved in the transport and metabolism of lipoproteins, affecting plasma lipid levels. Children can have monogenic inheritance, such as familial hypercholesterolemia caused by LDL-C receptor deficiency and familial hypercoeliac disease triggered by a defect in the lipoprotein lipase (LPL) gene; or polygenic inheritance, such as familial polygenic hypercholesterolemia. ② Long-term interaction between the body and environmental factors (dietary habits, lifestyle, etc.), such as long-term excessive intake of sugar, can affect the secretion of insulin, accelerate the synthesis of hepatic very low-density lipoproteins, resulting in hypertriglyceridemia; long-term excessive intake of cholesterol and animal fats, which will easily cause hypercholesterolemia. Because of this, primary hyperlipidemia may also have a certain racial and geographic predisposition. The etiology of secondary dyslipidemia is divided into exogenous and endogenous: ① Exogenous factors: including long-term application of drugs affecting lipid metabolism (e.g., glucocorticosteroids, anticonvulsants), ethanol (frequent excessive alcohol consumption) and smoking (and passive smoking), etc.; ② Endogenous factors: mainly refers to systemic systemic diseases affecting lipid metabolism. Endocrine and metabolic diseases, such as obesity, metabolic syndrome, hypothyroidism, cortisolism, diabetes mellitus, etc.; can also be caused by cancer chemotherapy, nephrotic syndrome, or biliary obstructive diseases such as bile duct stenosis, biliary cirrhosis. [Diagnosis] Children and adolescents with dyslipidemia have insidious onset, slow progress, symptoms and signs are not obvious, and their diagnosis mainly relies on laboratory tests. 1, the clinical manifestations of severe familial hyperlipidemia children may have the following clinical manifestations: ① yellow tumor, the Department of lipid deposition in the dermis formation; was a papule or nodule-like skin elevation, yellow or orange, diameter 2 ~ 5mm, mostly in the elbow, femur, buttocks. Lipoid corneal arches, formed by lipid deposition in the cornea. Liver and spleen enlargement due to massive phagocytosis and absorption of lipoprotein by liver and spleen macrophages; liver ultrasound can show fatty liver. ④ Early onset coronary artery disease or stroke, due to AS caused by lipid deposition in the vascular endothelium; although rare in children and adolescents, it has been reported. When the child presents with unexplained chest pain, left shoulder radiating pain or headache, it should be alerted. ⑤ Vascular ultrasound Doppler: carotid artery and abdominal aorta may show intima-media roughness, middle layer thickening, and altered blood flow spectrum. 2, high-risk groups of lipid screening children and adolescents at high risk of dyslipidemia include: ① genetic factors (family history of cardiovascular disease or dyslipidemia); ② dietary factors (high-fat, high-cholesterol diet); ③ disease factors (hypertension, obesity / overweight, diabetes mellitus, metabolic syndrome, Kawasaki disease, end-stage renal disease, cancer chemotherapy, etc.); ④ long-term application of medications affecting lipid metabolism (eg, glucocorticoids, etc.); ⑤ long-term application of drugs affecting lipid metabolism (such as glucose). Long-term use of drugs affecting lipid metabolism (e.g., glucocorticoids, etc.); ⑤ Smokers and passive smokers. For children and adolescents with the above risk factors, it is recommended that they should be screened for lipids once every 3 to 5 years, i.e., testing the levels of TC, TG, LDL-C, and HDL-C in the early morning fasting blood. If abnormalities are found, the test should be repeated within 1 to 2 weeks. 3.Diagnostic criteria of dyslipidemia for children and adolescents over 2 years of age are shown in Table 1; children under 2 years of age have unstable lipid levels and there is no reference standard for dyslipidemia. 4, dyslipidemia classification after laboratory examination to determine hyperlipidemia, should be further clarified is primary or secondary hyperlipidemia, and according to the clinical classification of dyslipidemia classification, in order to facilitate the selection of drugs and cause-specific treatment. Clinical classification: (1) Hypercholesterolemia: fasting blood TC↑. (2) Hyperglyceridemia: fasting blood TG↑. (3) Mixed hyperlipidemia: fasting blood TC and TG are ↑. (4) Low high-density lipoprotein anemia: fasting blood HDL-C ↓. Differential diagnosis] The differential diagnosis of dyslipidemia in children is mainly the identification of secondary hyperlipidemia. The most common diseases causing hyperlipidemia in children include simple obesity, metabolic syndrome, nephrotic syndrome and so on. 1, simple obesity children due to eating more, less activity and lead to excessive accumulation of body fat, can be accompanied by elevated blood lipids, thickening of subcutaneous fat, weight more than 20% of the average standardized body weight calculated according to the height, or more than the average standardized body weight calculated according to the age plus two standard deviations (SD). 2.Metabolic syndrome is a group of complex metabolic disorder syndrome, the main clinical manifestations of central obesity, accompanied by hypertension, hyperlipidemia and hyperglycemia. 3.Nephrotic syndrome is a group of clinical syndromes caused by a variety of etiological factors with increased permeability of glomerular basement membrane as the main change. Typical manifestations are “three highs and one low”, i.e., large amount of proteinuria, hypoproteinemia, high degree of edema and hyperlipidemia. Dietary intervention is a necessary and preferred treatment measure for children with dyslipidemia, regardless of the cause. It is necessary to adjust the diet structure, change eating habits, adopt reasonable nutritional patterns, and reduce the intake of saturated fatty acids and cholesterol. The aim is to reduce blood cholesterol levels and to achieve the desired goals of LDL-C <110mg/dl (2.85mg/L) and TC <170mg/d1 (4.40mg/L) as much as possible. The dietary intervention can be divided into the following two sets of dietary programs (Table 2). The first dietary regimen is usually chosen first, and the second dietary regimen is changed when the efficacy is not satisfactory for more than 3 months. Attention was paid to regular lipid testing to determine efficacy. The type, extent and start time of dietary intervention should be individualized and monitored, taking into account a variety of factors such as the child's age, type of hyperlipidemia, responsiveness and compliance to treatment. It is important to meet the growth and developmental needs of children, and it is not advisable to excessively restrict cholesterol intake while ensuring adequate supply of energy, vitamins and minerals. Since polyunsaturated fatty acids can promote the oxidation of cholesterol in the liver to bile acids and their excretion, the consumption of polyunsaturated fatty acids (e.g. linoleic acid, linoleic acid, peanut oil, corn oil, etc.) should be the mainstay of dietary intervention, and this is more important than simply restricting the intake of cholesterol. Dietary interventions should be implemented in a gradual, step-by-step manner. If the beginning is to reduce the intake of food rich in high cholesterol and saturated fatty acids, eat less animal offal, egg yolk, lard, fast food, etc.; further reduce the intake of meat, fish, chicken, duck, etc.; patients with severe hyperlipidemia, the transition should be gradual to cereals, legumes, fruits, vegetables-based. Cooking methods should be baked, grilled, steamed, boiled, try not to fry. Dietary interventions for infants and children under 2 years of age are usually not advocated to prevent growth disorders due to inadequate energy intake and lipid-vitamin deficiencies. However, the U.S. 2012 guidelines for the management of dyslipidemia and the prevention of atherosclerosis suggest that infants and young children who have a family history of obesity or cardiovascular disease can be advised to drink low-fat milk from 12 months of age. 2, exercise intervention in children and adolescents with dyslipidemia another proven non-pharmacological treatment is regular exercise, for obesity or metabolic syndrome associated hyperlipidemia, exercise intervention is particularly applicable. Aerobic exercise (brisk walking, jogging, swimming, etc.) can not only control body weight, but also improve dyslipidemia by lowering serum TC, TG, and LDL-C levels, and increasing the proportion of HDL-C and the activity of apolipoprotein Al. A practical exercise prescription suitable for Chinese children's physique has been developed in China. Exercise for at least 30 minutes a day and be active at least 5 days a week for a long time. However, attention should be paid to pediatric exercise protection, preferably under the leadership of a specialized coach to avoid skeletal muscle injury. Children's dietary intervention and exercise intervention should not be implemented alone, both at the same time, together with the family school education in order to change the child's bad habits, can receive the best results of non-pharmacological treatment. 3, drug therapy in the past on children and adolescents dyslipidemia drug treatment period and method of more controversial. 2009 "children and adolescents dyslipidemia prevention and treatment of expert consensus" put forward, children and adolescents can be applied to drug treatment of hyperlipidemia, but there are the following strict indications: children over the age of 10 years, dietary treatment for 6 months to 1 year is ineffective, LDL-C ≥ 4.92mmol / L ( 190 mg/dl) or LDL-C ≥4.14 mmol/L (160 mg/dl) with: (i) a definite family history of early-onset coronary heart disease (<55 years old at the onset of a first-degree male relative and <65 years old at the onset of a first-degree female relative); and (ii) concurrent presence of two or more coronary heart disease risk factors in children with failure of control, can be treated with drug therapy. The age of pharmacologic lipid-lowering therapy can be appropriately advanced to 8 years of age for the pure subtype of familial hypercholesterolemia. The appropriate lipid-lowering drugs for children and adolescents include: (1) Statins: i.e., cholesterol biosynthesis rate-limiting enzyme inhibitors (HMG-CoA reductase inhibitors), which are particularly suitable for children with familial hypercholesterolemia. Their main effect is to inhibit the hepatic synthesis of endogenous cholesterol without affecting enzyme or hormone secretion and without interfering with growth and sexual maturation. Dosage: Start with the lowest dose, taken at bedtime, and test fasting lipid levels after 4 weeks, with a treatment goal of LDL-C <3.35mmol/L (130mg/dl). If the therapeutic goal was achieved, the medication was continued and the test was repeated after 8 weeks and 3 months; if it was not achieved, the dose was doubled and the test was repeated after 4 weeks, and the dosage was gradually increased to the maximum recommended dose. The ideal goal of treatment is LDL-C <2.85 mmol/L (110 mg/dl). Adverse drug reactions, especially myopathy and hepatic damage, should be prevented during dosing, and creatine phosphate kinase (CK) and liver function should be monitored. (2) Bile acid chelating agent: also known as bile acid binding resin, is an alkaline anion exchange resin. Its role is to bind with bile acids, affecting the hepatic and intestinal circulation, increasing the excretion of cholesterol and bile acids, and at the same time, enhancing the activity of hepatic LDL-C receptor, reducing the level of LDL-C in the blood. The drug is not absorbed by the organism, highly effective and safe, suitable for children. The representative drug is cholestyramine (cholestyramine), usage: 0.3g/(kg.d), oral, twice a day, according to the response, gradually adjust the dose, the maintenance amount of no more than 2 ~ 4g / d. The drug has no obvious side effects, the oral a bit of odor, which may affect the children to take; a small number of children with steatorrhea; long-term use of the fat-soluble vitamins may affect the absorption of fat-soluble vitamins, the use of the drug at the same time should be supplemented with vitamins A, D, E, K. (3) Nicotinic acid, a kind of tobacco, a kind of tobacco, (3) Niacin: adult hyperlipidemia prevention and treatment guidelines recommend routine use of drugs. In the body of nicotinamide adenine dinucleotide (NAD) coenzyme system into NAD to play a lipid-lowering effect, can make TC, LDL-C and TG levels down, and make HDL-C levels rise. Although China's "Expert Consensus on Prevention and Treatment of Dyslipidemia in Children and Adolescents" does not recommend niacin as a routine lipid-lowering drug for children and adolescents, because of its small clinical side effects, "Zhufutang Practical Pediatrics" suggests that children can be applied, and the dosage: 0.15mg/(kg.d). 4, primary treatment of pediatric secondary hyperlipidemia, not only to treat the surface, but also to treat the root cause, that is, actively treat the primary disease. Commonly, there are endocrine or metabolic diseases, such as hypothyroidism, cortisolism, diabetes mellitus, nephrotic syndrome, lipodystrophy, etc.; biliary obstructive diseases, such as bile duct stenosis, biliary cirrhosis, etc.; renal diseases, such as nephrotic syndrome, chronic renal failure.