Intestinal Tuberculosis Mimicking Crohn’s Disease

Abstract

Introduction: Tuberculosis (TB) may involve any organ system including intestines. Intestinal TB (ITB) mimics Crohn’s disease (CD), and it may be difficult to differentiate between these two. In developed countries, the incidence of intestinal TB is very low and more commonly seen in immigrant population. We report a case of ITB initially diagnosed as CD. Case Report: A 58-year-old male from China was referred to our institute for second opinion regarding initiation of infliximab for unremitting CD. Prior to presentation at our institute, he was seen at an outside hospital for abdominal pain, diarrhea, and weight loss. Computed tomography (CT) abdomen showed thickening in terminal ileum (TI) and mesenteric lymphadenopathy. Colonoscopy showed ulcers in TI and ileocecal valve with biopsies showing mild inflammation in the TI, ulcer in the cecum, and normal colonic mucosa. He was started on budesonide with initial improvement in his symptoms. His symptoms worsened again, so he was started on azathioprine. A repeat CT abdomen showed thickening in the TI, along with the inflammation spreading to the mesentry and mesenteric lymphadenopathy up to 2.7 cm in size. This was thought to be reactive and secondary to CD. A CT chest was also done, which showed nodules in the right upper lung and raised concern for TB. While being considered for infliximab infusion, quantiferon TB gold was tested, which came back as positive. We repeated colonoscopy that showed circumferential ulcers in TI and cecum. Biopsies showed ulceration with poorly formed granulomas and positive acid fast bacilli (AFB) stain for AFB. During colonoscopy, a perforation was noted in sigmoid colon. He was taken for surgery with resection of ileocecal segment, primary closure of sigmoid colon perforation, and ileostomy formation. Histopathology showed TB enteritis, necrotizing granulomatous inflammation, and AFB. In the meantime, he was also found to have positive sputum culture for mycobacterium TB. He was started on 4-drug anti-TB treatment with significant improvement in symptoms. After finishing the anti-TB treatment for 1 year, he is currently doing well. Discussion: ITB is a rare disease in the developed world and is more common in immigrants, patients with AIDS, prisoners, and nursing home patients. Most common presentation of ITB is right lower quadrant pain, seen in 90-100% of patients, followed by weight loss (66%), fever (35-50%), and change in bowel habits (20%). Due to its rarity in the developed countries, it may be misdiagnosed as CD. Patients may have drastic complications on steroids and/or immunosuppressive therapy. Early differentiation is needed for effective management of this treatable disease and to avoid complications.