Cholecystitis (Greek, -cholecyst, "gallbladder", combined with the suffix -itis, "inflammation") is inflammation of the gallbladder. Although most people with gallstones do not have symptoms and will not go on to develop cholecystitis, cholecystitis occurs most commonly due to blockage of the cystic duct with gallstones (cholelithiasis). This blockage causes a buildup of bile in the gallbladder and increased pressure within the gallbladder, leading to right upper abdominal pain. Concentrated bile, pressure, and sometimes bacterial infection irritate and damage the gallbladder wall, causing inflammation and swelling of the gallbladder. Inflammation and swelling of the gallbladder can reduce normal blood flow to areas of the gallbladder, which can lead to cell death due to inadequate oxygen.