S5189 Gastrointestinal Tuberculosis: An Uncommon Case

Introduction: Tuberculosis (TB), caused by Mycobacterium tuberculosis, was the most prevalent infectious disease globally before the COVID-19 pandemic, with pulmonary TB being the primary presentation. Extrapulmonary TB (EXPTB) can also occur, with gastrointestinal TB (GITB) being the most frequent infection. Here, we present a case of abdominal TB. Case Description/Methods: A 34-year-old man with no past medical history presented with 7 days of abdominal distension. He had recently moved to Japan 9 months ago from Nepal. Symptoms include early satiety, cough, subjective fevers, and unintentional 20 lbs weight loss over 9 months. He denied abdominal pain or hemoptysis. His vital exams were unremarkable, and physical exam revealed a distended but non-tender abdomen. No pathogenic organisms were isolated from 3 sputum cultures. Abdominal computed tomography (CT) scan revealed bilateral pleural effusion and large volume ascites with peritoneal thickening, raising concern for peritoneal carcinomatosis or disseminated malignancy. Paracentesis was performed. The patient underwent esophagogastroduodenoscopy (EGD) and colonoscopy. EGD showed gastric mucosal erosions with gastric biopsy revealing inflamed gastric mucosa. Colonoscopy revealed a ring-like ulcer in the ascending colon. Biopsy of the ulcer was positive on Ziehl-Neelsen staining, polymerase chain reaction (PCR), and culture confirming Mycobacterium tuberculosis. The patient was diagnosed with tuberculous peritonitis and intestinal tuberculosis. He was started on a 4-drug TB regimen. Follow-up sputum cultures at 2 weeks remained negative. Discussion: Abdominal TB accounts for 1%-3% of all TB cases worldwide. While TB can affect any part of the gastrointestinal tract, the ileocecal region is the most commonly involved site, with some studies also highlighting the ascending colon as a frequent site. Diagnosis of GITB is challenging due to its non-specific symptoms. Ascitic fluid is typically straw-colored, with a white cell count of 500-1500 cells/mm3, protein >2.5 g/dL, and serum-ascites albumin gradient <11 g/L. Adenosine Deaminase levels >30 U/L have a 94% sensitivity for diagnosis. Imaging may show peritoneal involvement, ascites, lymphadenopathy, and bowel wall thickening; however, microbiological diagnosis via endoscopic biopsy has a 100% specificity and positive predictive value. Treatment is a 6-month course of standard anti-TB therapy.