An empyema is an abscess in the gallbladder. It may be a complication of acute cholecystitis or the result of infection of a mucocoele.
The gallbladder is distended with pus and may be palpable. Often there is a swinging pyrexia. Part of the gallbladder wall may become necrotic causing perforation. This is often walled off by the omentum, forming a localised abscess, and may present as a palpable gallbladder mass. Sometimes a perforation from the gallbladder may lead to the formation of a subphrenic abscess or a generalised peritonitis. However, necrosis is rare because of the rich blood supply to the gallbladder from both the cystic artery and the hepatic bed.
The empyema must be drained at once. This can usually be achieved by ultrasonic or radiographic (CT)-guided placement of a pig tail catheter. If this is not possible, the gallbladder must be drained surgically. Occasionally, a cholecystectomy is possible and safe.