Acute cholecystitis is an acute inflammatory disease of the gallbladder wall caused by chemical irritation (concentrated bile or pancreatic juice returning to the gallbladder) and bacterial infection. Chronic cholecystitis is a chronic inflammatory lesion of the gallbladder, the majority of which coexist with cholelithiasis and are called chronic lithotripsy. Chronic cholecystitis has a chronic onset and can also come from repeated episodes of acute cholecystitis. Because chronic nonstone cholecystitis is rare, the diagnosis cannot be made solely on the basis of roughness or thickening of the gallbladder wall.