Outline the pathophysiology, diagnosis and management of acalculous cholecystitis in the critically ill.
Pathophysiology (2 marks)
Acalculous cholecystitis is caused by gallbladder stasis from hypomotility that leads to increased intraluminal pressures in the gallbladder wall, resulting in ischemia, inflammation, and potential necrosis. Stasis can lead to bacterial colonisation and progress to infection.
Note: It was important to appreciate that hypomotility is the cause of stasis in this case as opposed to obstruction in the case of calculous cholecystitis
Diagnosis: (4 marks)
Often associated with severe critical illness, trauma or burns, period of “shock” state e.g. post-cardiac arrest, prolonged fasting/on TPN.
History and physical examination generally unreliable – may have abdominal signs.
Features of systemic inflammation, including fever, raised WCC, septic shock, general deterioration during critical illness, but these are non-specific.
May be elevation of LFT’s but again non-specific.
Diagnosis usually based on consideration of possibility when investigating fever or shock in critically ill patient.
Radiology is mainstay of diagnosis
Ultrasonography is most reliable and convenient method- Increased GB wall thickness is primary diagnostic criteria (>3.5mm) Other signs include oedema, peri-cholecystic fluid, intramural gas.
Other imaging modalities:
CT scan- sensitive, not very specific
Cholescintigraphy (HIDA-CCK scan- measures ejection fraction of the GB (<35% abnormal) in response to CCK- time consuming and requires transport of critically ill patient )
Management: (4 marks)
Either single agent regimen; Piperacillin/Tazobactam or Meropenem Or combination regimen; Cefepime or Ceftazidime plus metronidazole
(Note: any suitable regime acceptable). Duration depends on achievement of source control
Very few candidates had any idea about hypomotility in the pathophysiology of the disease. Knowledge gaps existed about pathophysiology, precise USS findings and role of cholecystostomy.
Historical risk factors
Laurila, Jouko, et al. "Acute acalculous cholecystitis in critically ill patients."Acta anaesthesiologica scandinavica 48.8 (2004): 986-991.
Wang, Ay-Jiun, et al. "Clinical predictors of severe gallbladder complications in acute acalculous cholecystitis." Heart 1500 (2003): 8.
Boland, Giles W., et al. "Percutaneous cholecystostomy in critically ill patients: early response and final outcome in 82 patients." American Journal of Roentgenology 163.2 (1994): 339-342.