Cholecystitis

Cholecystitis is inflammation of the gallbladder, most often caused by a blockage in the cystic duct.

Gallstones are the usual cause, but critically ill patients may develop acalculous cholecystitis due to bile stasis and reduced blood flow.

The pathophysiology begins with bile trapped inside the gallbladder, leading to increased intraluminal pressure.

As pressure builds, venous outflow is restricted, followed by impaired lymphatic drainage. The resulting congestion causes swelling and tissue hypoxia.

As oxygen delivery continues to decline, ischemia develops, especially in the fundus, the gallbladder's most distal and least well-perfused part.

This lack of oxygen damages the mucosal lining and triggers an inflammatory response. Neutrophils infiltrate the gallbladder wall, and retained bile salts further irritate the tissue.

If the condition progresses, the wall may become necrotic or even perforate.

Secondary bacterial infection may develop in cholecystitis, commonly involving Escherichia coli or Klebsiella species.