Abdominal Imaging Versus Tissue Biopsy: A Challenging Case of Abdominal TB

Document Type

Conference Proceeding

Publication Date

10-1-2024

Publication Title

Am J Gastroenterol

Abstract

Introduction: Tuberculosis, caused by Mycobacterium tuberculosis, remains 1 of the leading infectious causes of death worldwide. It is classified as either pulmonary or extrapulmonary. The gastrointestinal system involvement in tuberculosis is rare. Case Description/Methods: A 22-year-old man, with no significant past medical history who recently immigrated from Yemen, presented with a 3-month history of abdominal pain, nausea/vomiting, 20-pound weight loss, intermittent fevers, and night sweats. Laboratory tests showed mild microcytic anemia (hemoglobin 11.2 g/L, mean corpuscular volume 67mm3), elevated ferritin, and low iron and total iron binding capacity levels. Computed tomography scan showed extensive soft tissue involvement in the mesentery, enlarged porta hepatis lymph node, mass on bowel loops and liver metastases suggesting peritoneal malignancy spread such as lymphoma (Figure 1). Biopsy revealed necrotizing granulomatous inflammation. Further workup included negative fungal culture, AFB sputum culture smear and MTB polymerase chain rection, AFB blood culture. An abdominal tissue culture was positive for M. tuberculosis, and a positive Quantiferon tuberculosis (TB) test confirmed the diagnosis of tuberculosis. Discussion: Tuberculosis can affect the gastrointestinal system most commonly the leocaecal region and is the sixth most common site of extrapulmonary TB. Bacteria reach the gastrointestinal tract via hematogenous spread, ingestion of infected sputum, or direct spread from adjacent areas. Pathological features include ulcers, fibrosis, bowel wall and omental thickening, enlarged lymph nodes and peritoneal tubercles. Peritoneal TB presents in 3 forms: wet with ascites, dry with adhesions, and fibrotic with omental thickening. Usually presenting with a lower abdominal pain, palpable mass or complications like perianal fistulae, obstruction, perforation, or malabsorption. Only 25% of cases show pulmonary lesions. Ascitic fluid analysis shows high protein, low SAAG, lymphocytic cells, and elevated ADA. Treatment involves at least 6 months of antitubercular therapy. This case highlights the diagnostic complexities associated with extrapulmonary abdominal tuberculosis, emphasizing the necessity for heightened clinical suspicion in high risk populations such as immigrants, immunocompromised individuals, and travelers to endemic regions. It also emphasizes the potential discordance between radiological findings and definitive diagnosis, highlighting the risk of anchoring bias. Maintaining a broad differential diagnosis early in the evaluation process can help minimize anchoring bias.

Volume

119

Issue

10

First Page

S3078

Last Page

S3079

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