Clinical Features and Outcomes of Paediatric Patients with Isolated Colonic Crohn's Disease

Objectives: Adult studies suggest that patients with isolated colonic Crohn's disease (L2 CD) exhibit unique characteristics differentiating them from patients with ileo-caecal (L1) CD and ulcerative colitis (UC). We aimed to characterize clinical features and outcomes of paediatric patients with L2. Methods: Retrospective data was collected through the Porto IBD group of ESPGHAN on paediatric patients with L2, L1 or UC at different time-points. Outcome measures included time to 1st flare, hospital admissions, initiation of anti-TNFα drug, stricture and surgery. Results: Three hundred patients were included: 102 L1, 94 L2 and 104 UC. Rates of hematochezia at presentation were 14.7%, 44.7% and 95.2%, while rates of fever were 12.7%, 26.6% and 2.9%, for patients with L1, L2 and UC, respectively (P < 0.001 for all comparisons). Skip lesions were identified in 65% of patients with L2, and granulomas in 36%, similar to L1 patients. Rates of ASCA and pANCA positivity significantly differed between the three groups: 25.4% and 16.7% for patients with L2, compared with 55.2% and 2.3%, and 1.8% and 52.9% for patients with L1 and UC, respectively. Response rates to exclusive enteral nutrition were comparable between L1 and L2 (78.3-82.4%), as was the response to oral steroids (70.4-76.5%) in the three groups. While times to 1st flare and admission were similar between groups, patients with L1 were commenced on anti-TNFα earlier. Moreover, stricturing phenotype and need for colectomy were very rare in patients with L2. Conclusions: Significant differences are observed in the clinical presentation and outcomes of paediatric patients with L2, compared to patients with L1 and UC.