(p. 885) Acute acalculous cholecystitis in the critically ill 

Acute acalculous cholecystitis (AAC) may occur in surgical or injured, critically-ill, and systemically-ill patients, with diabetes mellitus, malignant disease, abdominal vasculitis, congestive heart failure, cholesterol embolization, shock, and cardiac arrest. Children may also be affected, especially following a viral illness. The pathogenesis of AAC is complex and multifactorial. Ischaemia/reperfusion injury and the associated pro-inflammatory response and oxidative tissue stress, appear to be the central mechanisms, but bile stasis, opioid therapy, positive-pressure ventilation, and parenteral nutrition may all contribute to development of the disease. Ultrasound of the gallbladder is most accurate for the diagnosis of AAC in the critically-ill patient. Computed tomography is probably of comparable accuracy, but carries both advantages and disadvantages. Percutaneous cholecystostomy is now the treatment of choice, controlling AAC in about 85% of patients, despite the known high prevalence of gallbladder infarction (~50%) and perforation (~10%). Rapid improvement may be expected when AAC is diagnosed correctly and cholecystostomy is performed timely. The mortality (historically ~30%) of percutaneous and open cholecystostomy are similar, reflecting the severity of illness, but improved resuscitation and critical care may portend a decreased risk of death.