Terminal Ileitis: Causes and Treatment
Terminal ileitis has multiple etiologies beyond Crohn's disease, including infectious causes, medication effects, and other inflammatory conditions, requiring targeted treatment based on the underlying cause rather than assuming it's always Crohn's disease. 1
Causes of Terminal Ileitis
Inflammatory Bowel Disease
- Crohn's Disease: Most common cause of terminal ileitis, characterized by transmural inflammation that can occur throughout the GI tract, with the terminal ileum being a common localization 2
- Ulcerative Colitis: Can present with "backwash ileitis" - continuous extension of inflammation from the cecum into the terminal ileum in up to 20% of patients with extensive colitis 2
Infectious Causes
- Bacterial infections (Yersinia, Salmonella, Campylobacter)
- Mycobacterium tuberculosis
- Parasitic infections
- Viral enteritis 3
Medication-Induced
- Non-steroidal anti-inflammatory drugs (NSAIDs) 4
Other Conditions
- Spondyloarthropathies
- Vasculitides
- Ischemic enteritis
- Eosinophilic enteritis
- Lymphoid hyperplasia
- Malignancies (lymphoma, adenocarcinoma)
- Sarcoidosis
- Amyloidosis 1, 3
Diagnostic Approach
Clinical Features Suggesting Crohn's Disease
- Younger age (median 27 years)
- Male predominance
- History of chronic abdominal pain
- Diarrhea
- Weight loss
- Anemia
- Higher platelet counts
- Lower mean corpuscular volume (MCV)
- Radiologic signs of complicated disease (strictures, fistulas) 5
Essential Diagnostic Tests
Laboratory evaluation:
- Complete blood count
- Inflammatory markers (CRP, ESR)
- Stool studies for infectious causes
- Fecal calprotectin (sensitive marker for intestinal inflammation)
Endoscopic evaluation:
- Ileocolonoscopy with biopsies
- Assess for characteristic features:
- Crohn's disease: Discontinuous inflammation, cobblestoning, deep ulcers
- Infectious: More diffuse, superficial inflammation
- NSAID-induced: Diaphragm-like strictures, superficial erosions
Imaging:
- CT or MR enterography to assess extent of disease and complications
- Particularly valuable for detecting strictures, fistulas, or abscesses 2
Treatment Approach
For Crohn's Disease Terminal Ileitis
Medical therapy:
- Corticosteroids for acute flares
- Immunomodulators (azathioprine, 6-mercaptopurine, methotrexate)
- Biologics (anti-TNF agents, vedolizumab, ustekinumab)
- Step-up approach based on disease severity 2
Surgical management:
- Consider for isolated terminal ileal Crohn's disease
- May be equally effective as medication-based treatment
- Can reduce need for long-term immunosuppression
- Indicated for strictures, fistulas, abscesses, or medically refractory disease 6
For Non-Crohn's Terminal Ileitis
- Infectious causes: Appropriate antimicrobial therapy
- NSAID-induced: Discontinuation of the offending drug
- Backwash ileitis in UC: Treatment directed at the underlying UC
- Vasculitis/spondyloarthropathies: Treatment of the underlying condition 3, 4
Important Clinical Considerations
- Misdiagnosis of Crohn's disease can lead to inappropriate treatment and potentially unnecessary surgery 4
- Terminal ileitis found incidentally during surgery for suspected appendicitis should not automatically lead to resection, as this carries risk of complications 2
- In cases of isolated terminal ileitis without clear etiology, a period of observation with follow-up endoscopy may be warranted before committing to long-term immunosuppressive therapy
Prevention of Recurrence in Crohn's Disease
For patients who undergo surgical resection for Crohn's terminal ileitis:
- Postoperative prophylaxis with thiopurines or anti-TNF agents is recommended
- High-dose mesalazine is an option for patients with isolated ileal resection
- Endoscopic surveillance is important to detect early recurrence 2