Acute acalculous cholecystitis

Acute acalculous cholecystitis (AAC) is a dangerous complication of medical and surgical illnesses, and it is most commonly encountered in the intensive care setting. Although uncommon, recent reports have indicated an increasing incidence. AAC occurs most often following major trauma or nonbiliary surgical procedures, but it may be seen in conjunction with a variety of medical illnesses as well. Transfusion, narcotics, mechanical ventilation, total parenteral nutrition, and sepsis have been associated with AAC, but it is likely that ischemic injury to the gallbladder is the most important pathogenetic factor. Primary infection of the biliary tract is not an important factor in the development of AAC, except in the acquired immunodeficiency syndrome. The incidence of gangrene and perforation is high in AAC in contrast to acute calculous cholecystitis. The clinical presentation may be highly variable; thus, a high index of suspicion is required for diagnosis. Fever, leukocytosis, and right upper quadrant tenderness are the most common findings. Early ultrasonography is appropriate when AAC is suspected, although computed tomography and cholescintigraphy may be useful in selected patients. Delay in diagnosis longer than 48 hours is associated with a perforation rate of 40%. Urgent cholecystectomy is the preferred treatment, but percutaneous cholecystostomy is an acceptable alternative in patients unable to withstand surgery.