Is Jejunal Crohn's Disease Rare?
Jejunal Crohn's disease is uncommon but not rare, occurring in approximately 8% of all Crohn's disease patients (about half of the 16% who have disease proximal to the terminal ileum). 1
Epidemiology and Clinical Significance
Crohn's disease proximal to the terminal ileum (L4 classification) occurs in 16% of patients, and approximately half of these will have jejunal involvement, making the true prevalence of jejunal disease around 8% of all Crohn's patients 1
Jejunal involvement represents a more aggressive disease phenotype with higher rates of stricturing disease, increased need for repeated surgery, and higher recurrence rates after surgical resection compared to isolated ileocecal disease 1
Patients with jejunal lesions demonstrate higher relapse rates over 2-year follow-up periods when assessed by capsule endoscopy 1
Clinical Implications for Management
Because jejunal Crohn's disease carries a poorer prognosis, patients should be considered for early introduction of biological therapy rather than following traditional step-up approaches 1
Key Management Principles:
Nutritional assessment and support is essential in all patients with jejunal or extensive small bowel disease, as malabsorption and nutritional deficiencies are common 1
Cross-sectional enterography (MRE or CTE) should be performed at diagnosis to detect the full extent of small bowel inflammation beyond the reach of standard ileocolonoscopy 1
Radiologists should report the number of involved bowel segments, approximate location (proximity to ligament of Treitz), and length of any strictures to guide therapeutic decisions 1
Diagnostic Considerations
Jejunal disease often presents in younger patients, with over 80% of cases developing before age 30 in patients with primary jejunal involvement 2
The terminal ileum may be spared in some cases of jejunal disease, making upper GI and small bowel imaging critical for complete disease assessment 2
Imaging findings of severe inflammation include wall thickness ≥10mm, intramural T2 hyperintensity, restricted diffusion, and small ulcerations on contrast-enhanced studies 1, 3, 4
Common Pitfall:
Do not assume disease is limited to the terminal ileum based on ileocolonoscopy alone—cross-sectional enterography is mandatory at diagnosis to identify proximal disease that would change management strategy 1