Which finding would indicate bowel perforation after a colonoscopy?

Which finding would indicate bowel perforation after a colonoscopy?

• A. Rebound tenderness with guarding
• B. Hypotension
• C. Absent bowel sounds
• D. Free air under the diaphragm on upright chest X-ray

Answer: (D)

Pneumoperitoneum from a bowel perforation is the most direct clue. If a perforation occurs during colonoscopy, gas from the colon escapes into the peritoneal cavity. The classic finding is free air under the diaphragm on an upright chest X-ray, because air rises and collects beneath the diaphragms, making it easily visible. This radiographic sign is highly specific for a perforation and typically prompts urgent surgical evaluation. Other signs like rebound tenderness with guarding indicate peritoneal irritation but aren’t definitive for perforation itself, hypotension can result from various causes, and absent bowel sounds reflect ileus or severe illness rather than a specific perforation finding. In suspected cases, an upright chest and abdominal radiograph (often followed by CT if needed) are used to confirm pneumoperitoneum and guide management.

Pneumoperitoneum from a bowel perforation is the most direct clue. If a perforation occurs during colonoscopy, gas from the colon escapes into the peritoneal cavity. The classic finding is free air under the diaphragm on an upright chest X-ray, because air rises and collects beneath the diaphragms, making it easily visible. This radiographic sign is highly specific for a perforation and typically prompts urgent surgical evaluation. Other signs like rebound tenderness with guarding indicate peritoneal irritation but aren’t definitive for perforation itself, hypotension can result from various causes, and absent bowel sounds reflect ileus or severe illness rather than a specific perforation finding. In suspected cases, an upright chest and abdominal radiograph (often followed by CT if needed) are used to confirm pneumoperitoneum and guide management.