The anatomical development of children varies by age and the pathology is naturally different. In newborns, the appendix is relatively short and thick and has a relatively large opening with a funnel-shaped root. The younger the age, the lower the incidence of pediatric appendicitis, which is clinically more common in school-aged children. The pathology of pediatric appendicitis is divided into the cicatricial, septic, gangrenous, and obstructive types. The khat type is only seen in the early stages of appendicitis in older children and may heal spontaneously in the late stages or turn into suppuration or gangrene; the typical suppurative pathology is mostly seen in infants and young children, starting from the submucosa with suppurative cell infiltration in all layers and an enlarged, scarlet, pus-filled appendix, with clinical abdominal pain and fever and significant local pressure pain, which soon spreads to peritonitis, especially in infants under 3 years old who have become peritonitis at the time of consultation. Diagnosis is confirmed by fever, abdominal distension, a harder abdomen, and pus in abdominal puncture; gangrenous type is mostly seen in school-age children, along with vascular embolism, rapid necrosis of the appendix, with little peripheral exudation, but early fibrin-purulent adhesions, easily forming limited. Abscess; obstructive type is mostly seen in ascaris appendicitis and pinworm appendicitis, no obvious changes in the appearance of the appendix, mostly in school-age children, clinical abdominal pain is severe but not heavy pressure pain, generally no fever, can be healed without secondary infection, worm exit, but ascaris has burrowing, can compress the tip of the normal appendix perforation, multiple ascaris from this burrowing into the peritoneal cavity, forming ascaris peritonitis, the main pathology from mechanical stimulation, no The main pathology comes from mechanical stimulation, no purulent pathological reaction, clinical abdominal pain, pressure pain, fever are not serious, the development of the disease is slow, there are chronic toxic symptoms, very similar to tuberculous peritonitis, but soon the occurrence of multiple intra-abdominal abscesses centered on ascaris, it is manifested as serious toxic symptoms, the mortality rate of misdiagnosed late cases is very high. The pathology of pediatric acute appendicitis develops rapidly. The course of the disease in older children is generally within one week and can also be divided into four stages: 1. Simple appendicitis stage Various inflammatory changes are within the appendiceal organ. Peripheral exudation is low and the reaction is mild. The infection gradually spreads outward after about 12 to 24 hours of onset. 2, the period of infection diffusion peritoneal inflammation around the appendix, there is pus, and gradually spread to the whole abdominal cavity for diffuse peritonitis. The younger the age, the faster it spreads, and after 48 hours, it is often the peritonitis phase. Clinically, there is fever, toxicity, abdominal distension, whole abdominal pressure and muscle tension. However, the right lower abdomen is still relatively significant. 3.Infection-limited stage Fibrin deposition in the exudate (pus moss), mutual adhesion of the appendix and surrounding organs, limiting the spread of infection, peripheral exudate begins to be absorbed, and an infiltrative mass is formed around the appendix, also known as the infiltrative stage. It is about the 3rd to 4th day after the onset of the disease and after 72 hours. The general condition of the child improves, with improvement in spirit and appetite compared to the previous day, but local pressure pain and muscle tension are prominent and limited. Rectal palpation and abdominal wall double diagnosis in the right lower abdomen with infiltrative mass and pressure pain. 4.Appendiceal abscess stage The infection is limited and gradually absorbed and healed. However, if the appendix has become a necrotic foreign body or a fecal stone is trapped in the abdominal cavity, it becomes the core of infection and forms an abscess, and the clinical fever is still present but the abdominal pain gradually decreases. The pressure pain is still present and a spherical mass about 5-10 cm in diameter can be palpated (double coaptation). It forms in about 1 week and often takes several weeks to gradually resolve. The progression varies according to the type of pathology and age, and abscesses rarely form in infants and children under 3 years of age and tend to develop into peritonitis. In children under school age, the diffuse phase is not obvious and transitions directly to the limited phase. However, gangrenous forms are more common in school-aged children, while necrotic appendixes tend to form abscesses. In addition, post-onset medication has an impact. Large amounts of antibiotics may facilitate the transition to the limited stage or delay the spread, limit the spread, and alter the clinical course.