Pediatric abdominal pain is one of the most common conditions seen in pediatric surgery clinics and a headache for parents. Parents are often overwhelmed by the crying caused by abdominal pain in infants and toddlers, and abdominal pain in school-age children often delays school and interferes with learning. Pediatric abdominal pain is commonly associated with functional disorders such as intestinal flatulence, gastroenteritis, enlarged abdominal lymph nodes due to upper respiratory tract infection, gastrointestinal dysfunction, and constipation. These diseases will disappear after medical or family management of abdominal pain symptoms. Among the surgical diseases causing abdominal pain in pediatric patients, organic diseases are common and often require hospitalization and surgical treatment to cure. These surgical diseases have different characteristics at different ages in pediatric patients: intussusception and incarcerated hernia are common in infants and young children, acute and chronic appendicitis in school-age children, and intestinal obstruction due to various causes. In addition, some uncommon to diseases, such as: congenital intestinal duct malformation, abdominal tumor, congenital hydronephrosis, Crohn’s disease, intestinal tuberculosis, etc. The clinical manifestations are often not specific, and irregular abdominal pain is the first symptom, which sometimes cannot attract sufficient attention of parents. If not treated in time, it can cause adverse consequences and even endanger life. So pediatric abdominal pain must go to a specialist hospital for a comprehensive examination to be safe! The following are the main surgical diseases that cause abdominal pain in children: a. Pediatric acute intussusception: pediatric acute intussusception can occur throughout the year, mostly in the spring and autumn during the active period of viruses and bacteria. From birth to school age can be onset, infants and young children more frequent. It is common in obese and healthy infants and young children within 2 years of age, with sudden onset. Intussusception can cause abdominal colic, which is characterized by the sudden onset of significant irritability and discomfort in previously quiet children, and may include generalized tonicity. The legs are flexed toward the abdomen, the expression is painful, and the symptoms are sudden and abrupt; inexpressible infants, there are bouts of crying and noise, with normal performance or quiet sleep between attacks. As the disease progresses, indifference and drowsiness may occur between episodes of abdominal pain. Vomiting is common, starting with undigested food, followed by vomiting of bile-like material, which may be followed by generalized writhing and breath-holding. In the early stage of intussusception, the child passes a small amount of normal stool, and later blood appears in the stool, followed by dark red blood clots or jam-like stool due to intestinal ischemia and necrosis. Etiology: Most of the causes of acute intussusception in pediatric patients are the consequences of intestinal dysfunction due to viral and bacterial infections, and a few are due to congenital intestinal malformations, tumors and other abdominal organic lesions. Physical examination of acute intussusception: at the onset of the disease, a mass of variable location can be palpated in the abdomen. The mass is usually curved or salami-shaped. Anal finger examination may reveal blood or blood-tinged mucus. The longer the duration of symptoms, the greater the amount of bleeding. Children with prolonged obstruction may develop dehydration and bacteremia, leading to tachycardia and fever, and occasionally hypovolemic or infectious shock. Untimely treatment can be fatal. Treatment is divided into conservative and surgical treatment. The majority of children who are seen in time are cured by conservative treatment. Some children with late presentation require surgical treatment to cure. Intussusception due to organic abdominal pathology also requires surgery to resolve the original pathology in order to cure. The primary cause of an incarcerated hernia is a pediatric inguinal hernia, also known as a “pediatric hernia”. The primary cause of an incarcerated hernia is a pediatric inguinal hernia, also known as a pediatric hernia. It is a common complication of pediatric hernia. Some children with no history of hernia may also present with an “incarcerated hernia” as the first symptom. The clinical manifestations of an incarcerated hernia include a painful mass in the groin or scrotum when a pediatric hernia becomes incarcerated. The child may suddenly cry or point his finger to the mass to indicate pain, and soon the symptoms of intestinal obstruction such as nausea, vomiting, cessation of defecation and exhaustion may occur. On examination, the doctor finds a bulging, hard and painful mass in the inguinal region, which cannot be returned to the abdominal cavity. If there are bloody stools and signs of poisoning, intestinal necrosis may appear, which is the most serious complication. Neonatal hernias have their own peculiarities and are not easy to detect, sometimes they are only manifested as inability to feed or vomit or they are seen as intestinal obstruction. In some cases, the intestinal canal and the ipsilateral testicle are found to be necrotic during surgery and have to be removed. Once a pediatric hernia is “stuck”, it should be taken to the hospital immediately. The treatment can be divided into two types: manual repositioning and surgical treatment. Pediatric appendicitis The peak incidence of pediatric acute appendicitis is between 6 and 12 years of age, and is less common in children under 5 years of age and even less common in children under 1 year of age. The onset of pediatric appendicitis is seasonally related, with a high incidence of appendicitis in March and April, when there are many upper respiratory tract infections, and in July and August, when there is a high incidence of gastroenteritis. The clinical manifestations of pediatric appendicitis: 1) Abdominal pain: Due to difficulties in history taking and narration, a typical history of metastatic abdominal pain is often not available, the abdominal pain is widespread, and sometimes abdominal pain is not the first symptom. 2) Gastrointestinal symptoms are often obvious and prominent. Vomiting is often the first symptom, and the vomiting is heavy and long-lasting, and may produce dehydration and acidosis due to massive vomiting and inability to eat. The symptoms are more severe, with early onset of fever, up to 39-40°C, and even seizures, hyperthermia, convulsions and seizures, which are due to the instability of the central temperature and the intense inflammatory response in young children. 4) Pressure pain and muscle tension The pressure point is mostly above the right lower abdominal wheal point. In infants and young children, the position of the appendix is high and the mobility is large, and the pressure point is on the inner upper side. Patience, gentleness and careful examination should be performed, with comparative examinations up and down, left and right. 5) Upper respiratory tract symptoms The incidence of upper respiratory tract infections in children is high, and these diseases may be a trigger for the development of acute appendicitis in children. Therefore, pediatric patients often have upper respiratory tract diseases before the clinical manifestations of acute appendicitis. Pediatric acute appendicitis has the following characteristics: 1) weak defenses of the pediatric organism , due to deficiencies in humoral immune function, lack of complement and poor phagocytosis of neutrophils, coupled with unstable thermoregulatory function. As a result, high fever, elevated leukocytes are more pronounced than in adults, and toxic symptoms are more severe. 2) Clinical symptoms of acute appendicitis in older children are similar to those in adults. The appendix wall is very thin and the muscle layer is less organized, so after inflammation, lymphedema is serious, which can cause appendiceal cavity obstruction and blood flow obstruction, so it is easy to perforate. The younger the appendix is, the higher the incidence of perforation, and after perforation, diffuse peritonitis is formed, and it is difficult to form limited abscesses by adhesion, which is due to the incomplete development of the greater omentum and too rapid perforation. Perforation can occur in septic appendicitis from 14 to 24 h after the onset of the disease. In contrast, diagnosis is difficult when the young age cannot accurately express the nature of abdominal pain and cooperate with physical examination. Treatment is based on the principle of early detection and early treatment, and surgical treatment should be performed once the diagnosis is clear. Some atypical appendicitis can only be diagnosed after consultation with an experienced specialist. Chronic appendicitis is also common in children, mostly in older children aged 7 to 12 years, and is thought to be a residual condition after the acute appendicitis has subsided. If there is a typical history of an acute appendicitis episode followed by persistent or recurrent right lower abdominal pain without other positive signs, chronic appendicitis is highly likely. Chronic appendicitis is often triggered by acute attacks due to strenuous activity, prolonged walking and poor diet. Some chronic appendicitis only presents with atypical symptoms such as loss of appetite, epigastric discomfort, nausea after rising in the morning, and acid reflux. There is some difficulty in diagnosis. In conclusion, the causes of abdominal pain in children are complex and the clinical manifestations are varied. The most scientific is to go to the hospital in time.