S4948 Unraveling the Diagnosis: Mycobacterial Infection Presenting as Suspected Inflammatory Bowel Disease

Introduction: Intestinal tuberculosis (ITB) is rare in developed countries but should be considered in high-risk populations due to its clinical and endoscopic overlap with Crohn’s disease (CD). This case highlights a young woman with suspected CD, later diagnosed with ITB and Mycobacterium avium complex (MAC) co-infection. It underscores the importance of thorough microbiologic testing in distinguishing ITB from inflammatory bowel disease. Case Description/Methods: A 30-year-old woman, born in Lebanon and living in Ecuador for 10 years, presented with a month of abdominal pain, nausea, vomiting, and fevers. Computed tomography showed terminal ileal hyperenhancement, suggesting CD. Despite steroids, symptoms persisted. Labs showed elevated C-reactive protein (134 mg/L), negative autoimmune and infectious serologies, and a positive TB Quantiferon®. Colonoscopy revealed ileal erosions and colitis with ulceration. Biopsies showed non-necrotizing granulomas, and acid-fast bacillus (AFB) staining and polymerase chain reaction confirmed Mycobacterium tuberculosis and MAC. She was treated with RIPE therapy (rifampin, isoniazid, pyrazinamide, ethambutol) and azithromycin for MAC, with symptom resolution. Discussion: ITB and CD share clinical and endoscopic features, including granulomas and ulceration, making differentiation challenging. While CD typically shows non-caseating granulomas, ITB may present with caseating granulomas and AFB. This case highlights the diagnostic value of AFB staining and polymerase chain reaction in patients with high-risk exposures or poor response to CD therapy. Early recognition and appropriate treatment of ITB are crucial to prevent complications and improve outcomes.