["Some patients who undergo ileal pouch-anal anastomosis (IPAA) surgery for ulcerative colitis (UC) or indeterminate colitis are subsequently diagnosed with Crohn's disease (CD). Making the diagnosis of CD in patients with IPAA can be difficult, but it is important for prognostic and therapeutic purposes. The aim of this study was to identify diagnostic features of CD in patients with IPAA.", "We evaluated 87 patients who had undergone IPAA for inflammatory bowel disease. Patients were classified as having UC (n = 28), CD (n = 27), or indeterminate colitis (n = 32) based on review of the original colectomy pathology and the postoperative clinical course. Each patient underwent a pouch endoscopy with biopsies of the pouch and afferent limb. Both the endoscopist and pathologist were blinded to the patient's diagnosis.", 'Afferent limb ulcers (ALUs) were seen on endoscopy in 12 of 27 patients with CD (45%) and 4 of 28 patients with UC (14%) (P = 0.019). After excluding patients who had taken nonsteroidal anti-inflammatory drugs (NSAIDs) within the past month, ALUs were found in 7 of 18 patients with CD (39%) and 0 of 17 patients with UC (P = 0.010). Controlling for NSAID use and smoking, the odds ratio for ALUs indicating CD was 4.67 (P = 0.03). In the UC population, ALUs were seen in 4 of 11 patients (36%) who had taken NSAIDs in the past month and 0 of 17 patients who had not taken NSAIDs (P = 0.016).'] Do afferent limb ulcers predict Crohn 's disease in patients with ileal pouch-anal anastomosis?