American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a key characteristic of acalculous cholecystitis compared to typical acute cholecystitis?

1. Presence of gallstones

2. It can occur without gallstones

3. Requires surgical intervention

4. Primarily results from viral infections

The correct answer is: It can occur without gallstones

Acalculus cholecystitis is characterized by inflammation of the gallbladder that occurs in the absence of gallstones, which distinguishes it from typical acute cholecystitis where gallstones are usually the underlying cause. This condition often occurs in patients who are critically ill or those with certain risk factors such as sepsis, trauma, or in a post-operative setting. This lack of gallstones in acalculous cholecystitis signifies a different pathological process; rather than obstruction of the cystic duct typically seen in acute cholecystitis due to gallstone disease, acalculous cholecystitis may result from ischemia or infection without the obstruction component. Recognizing this difference is crucial for proper diagnosis and treatment strategies, which may vary significantly due to the absence of gallstones in acalculous cases. Other aspects, such as surgical intervention and associations with viral infections, do play roles in the management and pathogenesis of acalculous cholecystitis but do not represent the key differentiating characteristic compared to typical acute cholecystitis.