On erect chest X-ray, free gas under the right hemidiaphragm is seen. Which of the following conditions does NOT cause pneumoperitoneum?
- A Perforated duodenal ulcer
- B Paralytic ileus ✓
- C Post-laparoscopic surgery (residual CO2)
- D Meckel's diverticulitis with perforation
Correct answer: B. Paralytic ileus
Explanation
Paralytic ileus causes dilated loops of bowel without free peritoneal air (no perforation). Causes of pneumoperitoneum include peptic ulcer perforation, post-surgical (laparoscopy) CO2, Meckel's perforation, colonic perforation, and coitus/pelvic examination in women (via fallopian tubes). Paralytic ileus is caused by intra-abdominal inflammation or drugs and features dilated small and large bowel gas without free air.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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