A 45-year-old man with ulcerative colitis for 12 years presents with acute severe bloody diarrhea and abdominal distension. Plain abdominal X-ray shows transverse colon diameter of 8 cm with loss of haustrations and mucosal islands. This complication is best described as:
- A Toxic megacolon ✓
- B Volvulus
- C Colonic perforation
- D Colonic obstruction
Correct answer: A. Toxic megacolon
Explanation
Toxic megacolon is defined as colonic dilatation greater than 6 cm with systemic toxicity, most commonly complicating ulcerative colitis. Loss of haustrations and mucosal islands (pseudopolyps projecting into the dilated lumen) are characteristic. Volvulus shows a single loop with coffee bean or bird beak sign. Perforation shows pneumoperitoneum. Obstruction shows proximal dilatation with distal collapse.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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