Hypoglycemia is generally considered to be when blood glucose falls below 2.6 mmol L-1 on more than two consecutive occasions at any age. The definition of hypoglycemia in neonates, preterm infants and low-birth-weight infants is controversial. The prevalence of hypoglycemia is 1.56% in low birth weight infants, 0.44% in full-term newborns, and 0.2% to 0.3% in older infants. Infants born to diabetic mothers are prone to hypoglycemia. Hypoglycemia is a common symptom in pediatrics, which can occur at any age, and many diseases can cause hypoglycemia. Normal children’s blood glucose mainly comes from carbohydrates in food, glycogen decomposition and gluconeogenesis, so that the blood glucose is maintained at 3~7mmol・L-1, blood glucose rises after eating, and the elevated blood glucose will be generated under the action of insulin and glycogen synthase, etc. Glycogen will be stored in the liver, and part of it will be transformed into fat storage. Blood sugar is normal, after fasting for 6~8h, fat will be decomposed under the action of enzymes and glucose will be generated through gluconeogenesis to maintain normal blood sugar and energy supply. In the process of glucose absorption, glycogen synthesis, glycogen decomposition and gluconeogenesis, carriers, enzymes and a variety of hormones need to be involved, therefore, such as insufficient food or reserves, overconsumption, defects of the relevant gluconeogenic enzymes, and the secretion of the gluconeogenic hormones involved in glucose metabolism is abnormal, Therefore, hypoglycemia can be caused by insufficient food or consumption, defects of relevant gluconeogenic enzymes, abnormal secretion of gluconeogenic hormones involved in glucose metabolism, and application of drugs and foods containing inhibitors of metabolic pathways. 2.1 Signs and symptoms of hypoglycemia. Typical acute hypoglycemia often manifests as hunger, weakness, cold sweat, pallor, cold limbs, headache, dizziness, drowsiness, and in severe cases, convulsive coma. Long-term chronic hypoglycemia often lacks typical acute hypoglycemia symptoms and signs, mainly manifested as physical growth retardation and neurological signs and symptoms, such as slow weight gain, short stature, psychomotor retardation, mental retardation, muscle weakness, epilepsy and so on. Neonatal hypoglycemia often manifests as tremor, shaking, cyanosis, convulsion, asphyxia, weakness, unresponsiveness, and shortness of breath. 2.2, signs and symptoms of primary diseases, in addition to symptoms and signs of hypoglycemia, children often have a history of primary diseases and signs and symptoms, ① low birth weight babies are mostly preterm or intrauterine growth retardation, hypoglycemia more than 24h after birth, diabetic mothers born to newborns with hypoglycemia more than a few hours after birth; ② hypoadrenocorticism in children with skin and mucous membrane pigmentation, dehydration, metabolic acidosis, electrolysis. acidosis, electrolyte disorders, low blood sodium and high blood potassium, low blood cortisol; ③ hypopituitarism in children with poor appetite, physical growth backward, short stature, low blood growth hormone levels, thyroxine, corticotropin; ④ hyperinsulinemic children hypoglycemia often occurs soon after meals, good appetite, with rapid weight gain, obesity, no hepatomegaly, acidosis, hyperlipidemia, blood glucose, insulin is often >10U. L-1, often need intravenous dextrose 5-10mg kg-1 min-1 to maintain normal blood glucose; ⑤ malnourished children are often accompanied by emaciation, low body weight, low subcutaneous fat, lack of or insufficient glucose-producing substances, and low hepatic glycogen reserves; ⑥ children with hepatic glycogen accumulation disease have backward growth, hepatomegaly, round face, hyperlipidemia, hyperuricemia, lactic acidemia, and hypoglycemia with no response to stimulation test with glucagon or adrenaline, and the liver biopsy does not respond to the stimulation test with glucagon or adrenaline. No response, liver biopsy glycogen accumulation; (7) glycogen synthesis defects, liver is not large, liver biopsy hepatic glycogen deficiency; (8) galactosemia is often seen in the neonatal period after eating milk jaundice, cataracts, vomiting, hepatosplenomegaly, cirrhosis, growth disorders, intellectual backwardness, amino aciduria; (9) fructose intolerance is often manifested in the consumption of fructose-containing foods vomiting, hypoglycemia, may be accompanied by hepatomegaly, growth disorders, and fructose intolerance is often manifested in the consumption of fructose-containing foods vomiting, hypoglycemia. Fructose intolerance is often characterized by vomiting and hypoglycemia on consumption of fructose-containing foods, which may be accompanied by hepatomegaly, growth disorders, and renal tubular acidosis; ⑩ ketotic hypoglycemia is most common in small, thin children and may be associated with insufficient secretion of adrenal medullary catecholamines, which is usually associated with ketosis in the early morning after infection, starvation, or a low-glucose high-fat diet; vomiting, hypoglycemic convulsions, hypoglycemia, and urine ketone positivity. Diagnosis Hypoglycemia can be diagnosed when blood glucose is less than 2.6 mmol・L-1. However, since hypoglycemia in some diseases often occurs in emergencies or under specific circumstances, it is very important to take a detailed medical history, family history, physical examination, and repeated laboratory tests. However, the induced test has the risk of aggravating the condition, so it should be carried out only under the supervision of experienced specialists and prepared for emergency measures. Treatment The treatment of hypoglycemia includes hypoglycemia treatment and primary disease treatment. In acute hypoglycemia, 10% glucose should be infused at a rate of 2.5mL kg-1 min-1 to raise blood glucose, and then 5-8mL kg-1 min-1 to maintain blood glucose at 4.2mmol L-1 or above. If glucose cannot be infused, glucagon 0.01-0.03mg kg-1, the maximum dose of 1mg intramuscular or subcutaneous injection, blood glucose rises in 5-10min, and the effect disappears in 40-60min, but it is ineffective in glycogen accumulation disease. Seriously ill children should pay attention to keep the airway open, oxygen, and establish effective circulation. The treatment of the cause of the disease includes dietary treatment and drug treatment. Hypoglycemic children should be fed with small amount and multiple meals depending on the time of blood glucose maintenance. Glycogen-accumulating disease children can use raw cornstarch, which can be eaten once in 3-5h, and glucose can be infused intravenously at 6-10mg kg-1 min-1 to maintain blood glucose. In galactosemia, lactose diet should be limited, in fructose intolerance, fructose diet should be limited, and in fatty acid β metabolism disorder, children should be fed before bedtime to avoid prolonged fasting. In multiple carboxylase deficiency, biotin should be given orally at 5-10mg d-1. Corticosteroid supplementation should be given to those with hypoadrenocorticism, and thyroid hormone, growth hormone and corticosteroid replacement therapy should be applied to those with hypopituitarism. For hyperinsulinemia, diazepam 5-15mg kg-1 d-1 in 3 doses can be used to inhibit insulin secretion. In cases of hyperinsulinemia where drug treatment is ineffective, subtotal (80%-90%) resection of the pancreas is performed.