Cholecystitis is inflammation of the gallbladder, which occurs most commonly due to obstruction of the cystic duct with gallstones (cholelithiasis). Blockage of the cystic duct with gallstones causes accumulation of bile in the gallbladder and increased pressure within the gallbladder. 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 insufficient oxygen. Not everyone who has gallstones will go on to develop Cholecystitis.
Risk factors for cholelithiasis and cholecystitis are similar and include increasing age, female sex, pregnancy, certain medications, obesity, rapid weight loss, and Native American or Mexican American ethnicity.