Question

A 60 year old obese female presents with abdominal pain, distension, and increased bowel sounds. There are multiple air fluid levels and air in the biliary tree on imaging. She also has a history of hysterectomy 2 years back. What is the probable diagnosis?

• A. Gall stone Ileus
• B. Small bowel obstruction
• C. Large bowel obstruction
• D. Paralytic ileus

Hint:

Look for Rigler's triad: small bowel obstruction + pneumobilia + ectopic gallstone -- a rare but classic cause of obstruction in elderly females.

Answer 1

The Correct Option is A

Step 1: Identify the key clinical and radiological findings.
The patient has: (1) abdominal pain and distension; (2) increased bowel sounds -- indicating mechanical obstruction (paralytic ileus would have absent bowel sounds); (3) multiple air-fluid levels on X-ray -- small bowel obstruction pattern; (4) air in the biliary tree (pneumobilia/aerobilia) -- the most critical clue.

Step 2: Interpret pneumobilia in this context.
Air in the biliary tree (pneumobilia) in a patient with small bowel obstruction is pathognomonic of gallstone ileus. It indicates the presence of a cholecystoenteric fistula -- an abnormal communication between the gallbladder and the small bowel through which a large gallstone has eroded and entered the bowel lumen.

Step 3: Recall Rigler's Triad.
Rigler's triad on plain X-ray is diagnostic of gallstone ileus: (1) small bowel obstruction; (2) ectopic gallstone (usually at the ileocaecal valve); (3) pneumobilia (air in the biliary tree). This patient has findings consistent with Rigler's triad.

Step 4: Why this specific patient?
Gallstone ileus is more common in elderly obese women -- this patient is 60 years old, obese, and female. It is an uncommon cause of mechanical small bowel obstruction accounting for 1-4% of cases but is the most common cause in elderly patients without prior abdominal surgery.

Conclusion: Gallstone ileus is the correct diagnosis based on Rigler's triad findings.