Clinical manifestations (1) Abdominal pain Typically, acute appendicitis starts with pain in the mid-upper abdomen or around the umbilicus, which shifts and fixes in the right lower abdomen after a few hours. The early stage is a kind of visceral nerve reflex pain, so the pain in the middle and upper abdomen and around the umbilicus is more diffuse and often cannot be localized exactly. When the inflammation spreads to the plasma membrane layer and the wall peritoneum, the pain becomes fixed in the right lower abdomen, and the original upper middle abdominal or periumbilical pain is reduced or disappears. Therefore, the absence of a typical history of metastatic right lower abdominal pain does not exclude acute appendicitis. (2) Gastrointestinal symptoms The gastrointestinal symptoms of simple appendicitis are not prominent. There may be nausea and vomiting in the early stage due to reflex gastric cramps. In pelvic appendicitis or perforated appendiceal gangrene, there may be increased frequency of defecation. (3) Fever Usually only low fever, no chills, and septic appendicitis usually does not exceed 38℃. High fever is usually seen in cases of gangrenous appendix, perforation or peritonitis. The presence of chills and jaundice suggests a possible complication of purulent portal phlebitis. (4) Induration and rebound pain Abdominal induration is a manifestation of inflammatory irritation of the wall peritoneum. The appendiceal pressure point is usually located at the Mai’s point, which is the junction of the middle and outer 1/3 of the line between the right anterior superior iliac spine and umbilicus. The pressure point may change with the anatomical location of the appendix, but the key is a fixed pressure point in the right lower abdomen. Rebound pain is also known as Blumberg’s sign. In patients with obesity or posterior appendicitis of the appendix, the pressure pain may be mild, but there is significant rebound pain. (5) Tension of the abdominal muscles This sign is present when the appendix is suppurating, and is particularly pronounced in gangrenous perforation complicated by peritonitis. However, in elderly or obese patients with weaker abdominal muscles, the presence or absence of abdominal muscle tension can only be determined by examining the contralateral abdominal muscles at the same time for comparison. Treatment (1) Non-surgical treatment Anti-infective treatment with antibiotics is available. Once the inflammation absorbs and subsides, the appendix can return to normal. When the diagnosis of acute appendicitis is clear and there are indications for surgery, but the patient’s circumstance or objective conditions do not allow, non-operative treatment can be taken first to postpone surgery. If acute appendicitis has combined with limited peritonitis and formed inflammatory masses, non-operative treatment should also be used to make the inflammatory masses absorb before considering elective appendectomy. Patients should be bed rested, fasted, and given intravenous input of water, electrolytes and calories, etc. (2) Surgical treatment In principle, acute appendicitis should be treated by appendectomy except for the mucosal edema type which can be cured after conservative treatment.