How is cholecystitis caused? Cholecystitis is divided into acute cholecystitis and chronic cholecystitis. Acute cholecystitis is a common acute abdominal condition with a predominance of female patients. Depending on the presence or absence of stones in the gallbladder, cholecystitis is divided into calculous gallbladder and non-calculous cholecystitis. Non-stony cholecystitis is less common. 1. Acute calculous cholecystitis is most often seen in old and seriously ill patients, such as trauma, burns, long-term parenteral nutrition, or patients after major surgery. Bile stasis and ischemia in the gallbladder may be the cause of the onset. This kind of cholecystitis often occurs with gallbladder necrosis, pus accumulation or perforation. Acute calculous cholecystitis is the most common complication of gallbladder stones, and its etiology is mainly due to obstruction of the gallbladder duct and invasion of pathogenic bacteria. Gallbladder duct obstruction is mostly caused by gallbladder stones, which can lead to increased pressure in the gallbladder due to obstruction of bile drainage and acute inflammation caused by local release of inflammatory factors in the gallbladder. Most pathogenic bacteria enter the gallbladder retrogradely through the cystic duct. Once the gallbladder bile drainage is poor or obstructed the environment within the gallbladder is conducive to bacterial reproduction and growth. 3, chronic cholecystitis is the consequence of repeated multiple episodes of acute cholecystitis or the long-term presence of gallbladder stones. It can lead to atrophy of the gallbladder, thickening of the cystic wall, and diminished gallbladder function. Most patients with chronic cholecystitis have significant connective tissue hyperplasia, lymphocyte and monocyte infiltration in all layers of the gallbladder wall. This leads to a significant decrease in the contractile function of the gallbladder.