A 28-year-old man presents with low-grade fever, evening sweats, right iliac fossa pain and diarrhoea. Colonoscopy shows ileocaecal valve deformity with a pulled-up caecum and transverse ulcers. Biopsy shows confluent granulomas with central caseation. Which finding most strongly favours intestinal tuberculosis over Crohn disease?
- A Non-caseating granulomas away from crypt rupture
- B Caseating granulomas with detection of acid-fast bacilli or Mycobacterium tuberculosis on PCR ✓
- C Skip lesions with cobblestoning on colonoscopy
- D Elevated faecal calprotectin with raised ESR
Correct answer: B. Caseating granulomas with detection of acid-fast bacilli or Mycobacterium tuberculosis on PCR
Explanation
Caseating granulomas plus demonstration of M. tuberculosis by AFB smear, culture or PCR is the definitive discriminator favouring intestinal tuberculosis, and anti-tubercular therapy is mandatory before immunosuppression. Non-caseating granulomas, skip lesions and cobblestoning all favour Crohn disease. Faecal calprotectin and ESR are nonspecific markers elevated in both conditions and cannot separate them.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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