**Question:** Acalculous cholecystitis is seen in

A. Acute viral hepatitis
B. Acute alcoholic hepatitis
C. Acute pancreatitis
D. Acute pyelonephritis

**Correct Answer:** A. Acute viral hepatitis

**Core Concept:** Acalculous cholecystitis refers to an inflammation of the gallbladder that does not involve the presence of gallstones (calculi). This condition can be caused by various factors.

**Why the Correct Answer is Right:** Acalculous cholecystitis is most commonly associated with acute viral hepatitis (mainly hepatitis A and E viruses) due to the direct viral invasion of the gallbladder wall, leading to inflammation. This is different from calculous cholecystitis, which is caused by the presence of gallstones (calculi) trapped within the gallbladder.

**Why Each Wrong Option is Incorrect:**

B. Acute alcoholic hepatitis is a liver disease caused by excessive alcohol consumption. Although alcohol can lead to cholestasis and potentially biliary tract inflammation, it is not directly associated with acalculous cholecystitis.

C. Acute pancreatitis is an inflammation of the pancreas, not the gallbladder. The pathophysiology of acalculous cholecystitis involves different mechanisms than those seen in acute pancreatitis.

D. Acute pyelonephritis is an inflammation of the kidney, not the gallbladder. The cause and pathophysiology of acalculous cholecystitis differ from that of acute pyelonephritis.

**Clinical Pearl:** Understanding the differences between acalculous cholecystitis and calculous cholecystitis is crucial for accurate diagnosis and appropriate treatment planning in clinical practice. While both conditions can present with similar symptoms, the underlying causes and management strategies are distinct.