Prepouch Ileitis - Does It Really Exist Or Is It a Misdiagnosis of Crohnʼs Disease?

Abstract

A 16-year-old girl presented with diarrhea, bloody bowel movements, abdominal cramps, tenesmus, and failure to thrive. Laboratory analysis revealed WBC=8.1 bil/L, HGB=11.4 g/dL, platelets=207 bil/L, Alk.P.=125 U/L. Other liver function tests and kidney function tests were normal. Colonoscopy and biopsy were consistent with extensive ulcerative colitis (UC). She was started on oral prednisone and infliximab (IFX). Her symptoms improved for few months then she relapsed. Extended release budesonide was added to IFX to control her symptoms. She started to develop IFX antibodies. IFX frequency and dosages were increased with no improvement in symptoms despite therapeutic IFX level. She underwent successful restorative proctocolectomy (RPC) with ileal pouch anal anastomosis (IPAA). She was symptom free for 1 year and then she started to develop persistent abdominal pain, and watery diarrhea (8-10 bowel movements). Stool culture, Clostridium difficile toxin, ova and parasite were negative. Ciprofloxacin and metronidazole were given for pouchitis. The patient symptoms improved partially. Colonoscopy showed moderate inflammation in the distal ileal pouch with some aphthous ulcers. Also, ulcerations were noted in the terminal ileum. Microscopic pathology of the ileal pouch showed chronic active inflammation compatible with pouchitis. Microscopic pathology of the terminal ileum (afferent limb) showed chronic active inflammation and ulceration compatible with prepouch ileitis (PPI). She continued her daily metronidazole and ciprofloxacin, which led to partial improvement of her symptoms. Later on, budesonide was used and azathioprine was added to control her symptoms. The patient is doing well for one year. RPC and IPAA is the operation of choice for UC when UC is refractory to medical treatment or in those who develop dysplasia or cancer. Pouchitis is the most common complication after RSC and IPAA. PPI occurs when inflammation extends into the afferent limb of the pouch. Some physicians suggested reclassifying PPI as Crohn's disease (CD) rather than UC with PPI. Inflammation proximal to the pouch has been recently recognized and described as PPI. PPI has distinct pathogenic and histologic features different from CD and it was mentioned that PPI demonstrates morphologic changes similar to pouchitis. The theory that PPI is an extension of inflammatory process of pouchitis is supported by the fact that PPI never occurred without pouchitis. The incidence of PPI is less than 6% from all UC patients who underwent RPC and IPAA. Once PPI is diagnosed, response to antibiotics is less likely, it is more refractory to treatment than pouchitis alone and escalation of treatment should be considered.