Acute cholecystitis is an inflammation of the gallbladder, typically caused by the obstruction of the cystic duct, which is the tube that transports bile from the gallbladder to the duodenum. The obstruction is often caused by the presence of gallstones, which are hard deposits of bile that form in the gallbladder. In some cases, the obstruction may be caused by a tumor, a stricture, or a pocket of pus.
The most common cause of acute cholecystitis is gallstones, which form when the bile produced by the liver is either too concentrated or contains too much cholesterol. This causes the bile to become thick and form crystals, which can then stick together to form gallstones. These stones can block the cystic duct, preventing the bile from draining properly and causing the gallbladder to become inflamed.
In some cases, acute cholecystitis can be caused by an infection, such as from a virus or bacteria. The infection can irritate the gallbladder, leading to inflammation and pain. It can also cause the gallstones to grow larger, which can further obstruct the cystic duct.
In rare cases, acute cholecystitis can be caused by an injury or trauma to the area, such as a tear in the gallbladder wall. This can cause the gallbladder to become inflamed and fill with fluid, leading to the symptoms of acute cholecystitis.
In summary, the main cause of acute cholecystitis is the obstruction of the cystic duct, typically caused by the presence of gallstones. In some cases, it can also be caused by an infection or injury.