Introduction Differentiating Crohn's disease from UC and IBDU is vital for children. Appreciable phenotypic differences exist between adult and paediatric-onset Crohn's disease (PCD) at diagnosis. Guidelines (JPGN 2010;50:S1–S13) for PCD diagnosis recommend assessment by upper-gastrointestinal endoscopy (UGIE), colonoscopy with terminal ileal (TI) biopsy and small-bowel imaging (SBI). We aimed to establish the relative contribution of each part of evaluation to PCD diagnosis.
Methods We performed a retrospective case note review on the cohort of PCD (diagnosis <17 years of age) patients from a regional PIBD centre from 1997 to 2009. Patients undergoing full endoscopic examination at first presentation including attempted TI biopsy, UGIE and SBI were included; pathology reports provided location of PCD defined by granulomatous inflammation.
Results Pathology and endoscopy reports were available for 105/114 (92%) patients with PCD undergoing full evaluation at diagnosis. TI biopsy was achieved in 63% (66/105). Histopathological-defining PCD features in TI alone were present in 11% (7/66). Diagnosis was achieved on the basis of SBI in 10% of all cases (10/105) with non-specific gastrointestinal histopathology for PCD including 5% of cases (3/66) where TI biopsy was achieved. Histopathological-defining PCD features were seen in UGIE alone in 8% (8/105); 7/8 cases included colonoscopy and TI biopsy where TI biopsy was not diagnostic. Sensitivity of colonoscopy alone for PCD was 77%; for colonoscopy+TI biopsy was 83%, improving to 90% when SBI was added and to 98% when UGIE was added to the evaluation (two patients had non-Crohn's specific intestinal inflammation with extra-intestinal granulomatous inflammation).
Conclusions Differentiation of PCD from UC can be challenging, requiring careful correlation of clinical, endoscopic, pathological and radiological findings. Our data strongly supports the recommendation that children suspected of IBD should have full endoscopic/radiological evaluation at diagnosis. Many children undergo evaluation by adult gastroenterologists, more accustomed to the adult CD phenotype, and may be tempted to forgo full ileocolonoscopy (IC) and UGIE. We demonstrate the need for both UGIE and IC, significantly improving diagnostic yield in PCD.