How is cholecystitis classified? It is well known that acute cholecystitis is mostly caused by bile duct obstruction and bacterial invasion. In the development of acute inflammation of the gallbladder, it can be divided into the following types: 1. Acute simple cholecystitis: the mildest type, characterized mainly by congestion and edema of the gallbladder wall and loss of mucosal epithelial cells, with mostly negative bacterial cultures. There are generally no obvious complications at this time, and most patients are cured with conservative treatment. 2, Acute pyogenic cholecystitis: At this time, the edema of the gallbladder wall is obviously worse, the gallbladder is enlarged due to obstruction of the cholecystic duct, pus may be present in the gallbladder, the serous membrane is dark red, purulent fibrin-like deposits may be seen on the surface of the gallbladder, and a large net may envelop the gallbladder to prevent the spread of infection into the abdominal cavity. This may occur. At this stage, the patient may show increased pain in the right upper abdomen, and the body temperature can rise significantly to 39 °C. 3, acute gangrenous cholecystitis At this time, the gallbladder is very dilated, the gallbladder serosa membrane changes black, swelling of the gallbladder can cause ischemic gangrene of the gallbladder wall, because continuous compression of the gallbladder wall by stones in the gallbladder can worsen necrosis of the gallbladder wall and eventually lead to perforation of the gallbladder. Complications such as diffuse peritonitis, portal veinitis, and even sepsis can occur in patients at this stage. This stage often requires urgent surgical treatment.