Objectives: Crohn disease (CD) has been diagnosed following colectomy for ulcerative colitis (UC). This study aims to determine the frequency of this occurrence, and to identify predictive factors leading to a CD diagnosis.
Materials and methods: A retrospective chart review was performed in patients who have undergone colectomy.
Results: From 1996 to 2006, colectomy was performed in 212 patients, 37 of whom were diagnosed preoperatively with UC. The mean ages at diagnosis and at colectomy were 10.6+/-4.3 years and 13.7+/-3.7 years, respectively. Inflammatory bowel disease serology at diagnosis in 29 patients showed that 26 (90%) were pANCA+. Serology was negative in 3. Ten (27%) had nonspecific inflammation of the upper digestive tract. Radiographs in 25 patients indicated no abnormalities in the small intestine. Before colectomy, patients (n=35) were treated with corticosteroid (97%), 5-ASA (69%), immunomodulator (66%), infliximab (29%), and cyclosporin (11%). The mean postoperative follow-up was 2.6+/-2 years. Six patients (16%) were found to have CD. All 6 patients were pANCA+ with elevated anti-OmpC (n=4), ASCA immunoglobulin A (n=2), and ASCA immunoglobulin G (n=1). The CD group had higher mean anti-OmpC compared with the UC group, 16.9+/-5.2 and 6.2+/-3.4, respectively (P<0.005). Weight z score at time of surgery was lower in the CD group (-1.38+/-0.79) than in the UC group (0.29+/-0.24), P<0.05.
Conclusions: The possibility of CD remains in a small fraction of patients who undergo colectomy for medically refractory UC. A lower weight and a higher anti-OmpC titer may be predictive of CD.