Acalculus cholecystitis (AAC) is a disease which is frequently unrecognized. It occurs due to gallbladder ischemia and bile stasis with an estimated incidence of 1.5%. It is common in septic patients or in patients recovering from abdominal sepsis. It is most commonly diagnosed in the ICU setting and diagnosis is often delayed due to the severity of underlying disorder.
Causes of Acalculus Cholecystitis are diverse and most commonly the patients are sick and being managed in ICU. These can be divided into
- Cardiac causes
- Abdominal aortic aneurysm 0.7 to 0.9%
- Valvular diseases and Post Coronary Artery Bypass Grafting.12%
- Congestive Heart Failure
- Trauma and Burns
- Diabetes Mellitus, Abdominal vasculitis
- Cholesterol embolization of the cystic artery
- Resuscitation from hemorrhagic shock or cardiac arrest
- Malignancy such as Leukemias
- Metastasis to Porta Hepatis
- PTBD (percutaneous trans hepatic biliary drainage procedures)
- BMT (Bone marrow transplant) 4%
- Secondary infection of Gall Bladder
- Obstructive Biliary system
The pathophysiology of Acalculus Cholecystitis includes
1.Bile Stasis due Dehydration which leads to inspissated bile.
2. Mucosal injury of the gall bladder wall.
3. Lysophosphatidylcholine is an agent in bile which is directly responsible.
4. Total parenteral nutrition
Gallbladder ischemia is central to the pathogenesis of AAC. An interrelationship between ischemia and stasis has been suggested, leading to hypo perfusion of the gall bladder It has been hypothesized that the fundamental lesion leading to AAC is failure of the gallbladder micro circulation with cellular hypoxia leading to cell death.
Jaundice caused by Acalculus Cholecystitis may be caused most often by sepsis-related cholestasis, or rarely by extrinsic compression of the common duct by stones.
AAC represents 50% to 70% of all cases of acute cholecystitis in toddlers and older children. Dehydration is a common precipitant, as are acute bacterial infections and viral illnesses, such as hepatitis and upper respiratory tract infections. Portal lymph adenitis with extrinsic cystic duct obstruction may be etiologic in viral infections. Recent reports suggest that the pathogenesis may be similar to that in adults
Ultrasound Abdomen is helpful in diagnosis and the ultrasound findings are-
Gallbladder wall thickness >3 mm, intramural lucencies, gallbladder distension, pericholecystic fluid and intramural sludge. CT Scan of the Abdomen has higher sensitivity in detecting acalculus cholecystitis.
Frequently, the diagnosis is delayed and the disease progresses to ischemia, gangrene and perforation.
Treatment at bedside is percutaneous cholecystostomy and some times cholecystectomy
The mortality of AAC is high in the range of 30% but effective early treatment can ensure cure.