Acalculous cholecystitis is inflammation of the gallbladder in the absence of stones. It may be acute or chronic, and often gives rise to a clinical picture similar to calculous cholecystitis. The cause may be non-specific or it may be due to one of the cholecystoses.

Acute forms are often seen in patients recovering from major surgery, trauma, burns, or multisystem failure. It is best confirmed by radioisotope scanning. The diagnosis is often missed and there is a 20% mortality.

Oral cholecystography is most useful in the diagnosis of those presenting chronically.