Acute cholecystitis occurs in approximately one-third of patients with gallstones.
In western countries, cholesterol stones predominate and is almost three times as high in women as it is in men. The incidence of acute cholecystitis increases with age and multiparity. Secondary sonographic criteria are less specific but include wall thickening of greater than 3 mm and ductal dilatation. Complications of acute cholecystitis include emphysematous and gangrenous cholecystitis as well as perforation.