Cholecystitis is inflammation of the gallbladder. It most commonly comes on suddenly (acute cholecystitis), due to a gallstone blocking the outflow of bile along the main duct leading out of the gallbladder.
The trapped bile causes irritation of the gallbladder, which may become infected. Rarely, acute cholecystitis may be due to other causes, such as a serious injury.
The main symptom of acute cholecystitis is severe, persistent pain in the upper right abdomen that spreads to the right shoulder. Other symptoms may include fever, nausea, vomiting, loss of appetite, and a bulge in the abdomen.
Treatment is usually with pain relievers, antibiotics, and surgery to remove the gallbladder