What is the primary etiology of terminal ileal ulcers in India?

Etiology of Terminal Ileal Ulcers in India

In India, the primary etiology of terminal ileal ulcers is intestinal tuberculosis, followed by Crohn's disease, non-specific ulcers, and infectious causes. 1, 2

Common Etiologies of Terminal Ileal Ulcers in India

Infectious Causes

• Intestinal tuberculosis is the most common cause of terminal ileal ulcers in India, reflecting the high endemic prevalence of tuberculosis in the region 1, 2
• Tuberculosis typically affects the ileocecal region and terminal ileum with characteristic features including circumferential ulcers, strictures, and occasionally perforation 1, 3
• Other infectious causes include Yersinia, Salmonella, Shigella, and Campylobacter species, which can cause acute terminal ileitis that may resolve with appropriate antimicrobial therapy 4

Inflammatory Bowel Disease

• Crohn's disease is the second most common cause of terminal ileal ulcers in India, characterized by transmural inflammation, skip lesions, and granulomas on histopathology 4, 2
• The incidence of Crohn's disease in India has been increasing in recent years, making differential diagnosis with tuberculosis particularly important 2
• Ulcerative colitis with "backwash ileitis" can present with terminal ileal ulcers in approximately 20% of patients with extensive colitis, showing continuous inflammation extending from the colon 1, 4

Non-specific Terminal Ileal Ulcers

• Studies from India have shown that approximately 40% of terminal ileal ulcers may be non-specific without a definitive etiology despite extensive workup 5
• These non-specific ulcers often resolve spontaneously without specific treatment, as demonstrated in a randomized controlled trial 6

Diagnostic Approach

Endoscopic Evaluation

• Ileocolonoscopy with multiple biopsies is the gold standard for diagnosis of terminal ileal ulcers 4, 7
• Endoscopic features that suggest tuberculosis include circumferential ulcers, patulous ileocecal valve, and cecal involvement 2
• Crohn's disease typically shows aphthous ulcers, longitudinal ulcers, and cobblestone appearance 1, 4

Histopathological Features

• Tuberculosis: Large granulomas, often multiple and confluent, with caseous necrosis and presence of acid-fast bacilli (though sensitivity is low) 1, 2
• Crohn's disease: Focal (discontinuous) chronic inflammation, transmural involvement, small non-caseating granulomas, and crypt architectural distortion 1, 4
• Non-specific ulcers: Mild to moderate inflammation without granulomas or specific features 5

Imaging

• Cross-sectional enterography (CT or MRI) helps assess the extent and severity of terminal ileal inflammation 4
• Tuberculosis typically shows asymmetric wall thickening, mesenteric lymphadenopathy with central necrosis, and ascites 2
• Crohn's disease shows symmetric wall thickening, "skip lesions," and "creeping fat" sign 4, 2

Microbiological Testing

• PCR-based tests for Mycobacterium tuberculosis from tissue samples have improved sensitivity compared to conventional AFB staining and culture 2
• Stool cultures for other infectious causes should be performed, especially in acute presentations 1, 4

Differential Diagnosis Challenges

Tuberculosis vs. Crohn's Disease

• Differentiating between intestinal tuberculosis and Crohn's disease is particularly challenging in India due to overlapping clinical, endoscopic, and histological features 2
• Misdiagnosis can lead to catastrophic consequences as tuberculosis requires anti-tubercular therapy while Crohn's disease needs immunosuppressive therapy 2
• In cases of diagnostic uncertainty in TB-endemic regions like India, a therapeutic trial of anti-tubercular therapy with assessment of early mucosal response at 2 months is often employed 2

Management Considerations

• For confirmed tuberculosis, standard anti-tubercular therapy for 6-9 months is recommended 1, 2
• For Crohn's disease, treatment options include 5-ASA compounds, immunomodulators, and biologics depending on disease severity 1
• Non-specific terminal ileal ulcers often resolve spontaneously without specific treatment, with studies showing no significant difference in outcomes between patients treated with mesalazine and those followed without intervention 6, 5

Complications and Prognosis

• Untreated tuberculosis can lead to strictures, perforation, and fistula formation 1, 3
• Crohn's disease has a chronic relapsing course with approximately 50% of patients requiring surgery within 10 years of diagnosis 1
• Non-specific terminal ileal ulcers generally have a favorable prognosis with most patients showing symptomatic and endoscopic resolution within 3-6 months 5