Makindo Medical Notes

Sigmoid Volvulus

🌀 Expected X-ray findings:
• Massively dilated sigmoid colon arising from the pelvis.
• Classic “coffee-bean” sign with the apex pointing to the right upper quadrant.
• Loss of normal haustral markings in the distended loop.
• Little or no gas in the rectum.
⚠️ If prolonged → risk of ischaemia and perforation (may coexist with free air).

Free Air (Pneumoperitoneum)

💥 Expected X-ray findings:
• Free gas under the diaphragm on erect chest X-ray (right side most sensitive).
• Rigler’s sign: both sides of the bowel wall visible.
• Football sign with large volumes of intraperitoneal air.
🚨 Indicates perforated viscus until proven otherwise → immediate surgical review.

Large Bowel Obstruction (LBO)

🚧 Expected X-ray findings:
• Dilated colon proximal to obstruction (>6 cm; caecum >9 cm).
• Visible haustra that do not extend fully across the bowel lumen.
• Little or no gas in the distal colon or rectum.
• If ileocaecal valve competent → minimal small bowel dilatation.
⚠️ Caecal diameter >12 cm suggests imminent perforation.

Small Bowel Obstruction (SBO)

🔄 Expected X-ray findings:
• Dilated central small bowel loops (>3 cm diameter).
• Valvulae conniventes visible across the full width (“stacked coins”).
• Multiple air–fluid levels on erect films (step-ladder pattern).
• Relative absence of gas in the colon.
⚠️ Early SBO may have a near-normal X-ray — CT abdomen is definitive.

🧠 Rapid Pattern Recognition (Exam & On-Call Pearl)

• 📍 Central loops + valvulae across full width → SBO
• 📍 Peripheral colon + haustra → LBO
• 📍 Single huge loop with direction → Volvulus
• 📍 Gas under diaphragm → Perforation until proven otherwise