Case Presentation: A 26-year-old female presented to the emergency department (ED) with weight loss, abdominal pain, nausea, vomiting, and severe constipation. The patient denied any typical symptoms of tuberculosis, such as night sweats, fevers, chills, cough, or difficulty breathing. Her temperature was 37.1°C, HR 95, respiratory rate 16, BP 120/70, SpO2 99% on room air. Labs were notable for hemoglobin 9.5, platelets 492, WBC 5.7, CMP unremarkable. CT scan of the abdomen showed evidence of a closed loop obstruction, without discrete transition point, no free intra-abdominal air, small to moderate amount of ascites with peritoneal thickening and subtle areas of nodularity, with no distinct mass. She had no family history of malignancy and no prior abdominal surgeries. During admission, labs showed negative HIV, coccidiosis serologies, Histoplasma Ab, and positive QuantiFERON-TB. Diagnostic paracentesis yielded 500 ml straw-colored fluid. SAAG was 1.0. Total cell count 835, 11% neutrophils, 77% lymphocytes, 9% monocytes, 2% eosinophils. Cytology was negative for malignancy but showed reactive mesothelial cells and chronic inflammation. Bacterial and fungal cultures were negative. Acid fast smear was negative for mycobacterium. She underwent ultrasound-guided biopsy of her left lower quadrant peritoneal nodule. Bacterial, fungal, and mycobacterial cultures from the nodule were all negative. Pathology revealed granulomatous inflammation with scattered acid-fast bacilli, consistent with chronic mycobacterial infection and negative for neoplasm. CT chest was obtained showing scattered sub-6 mm bilateral upper lobe pulmonary nodules. Infectious disease was consulted, and she was started on isoniazid 300 mg PO daily, rifampin 600 mg daily, pyrazinamide 1000 mg/d and ethambutol 800mg/d and pyridoxine 50 mg daily. Upon treatment, her bowel function returned, and her diet was advanced.
Discussion: Tuberculosis is a highly infectious disease and a leading cause of death worldwide.[11] Approximately 10.6 million new cases develop each year.[11] It is particularly endemic in sub-Saharan Africa and Southeast Asia.[11] It is much less common in the United States, with 3 out of 100,000 cases reported yearly.[15] Instances of tuberculosis seeding the peritoneum are exceedingly rare, accounting for 1-2% of all cases.[10-11] Closed loop obstruction is an uncommon complication of peritoneal tuberculosis; further, she was not immunocompromised and had atypical symptoms, adding to the case complexity.[6] Diagnostic paracentesis highlights the low sensitivity of ascitic fluid analysis for tuberculosis, as acid-fast smears are often negative, with sensitivity rates below 50%, and cytology is typically non-diagnostic.[12-14] Tuberculosis was confirmed by peritoneal nodule biopsy, showing the importance of utilizing a definitive diagnostic tissue-based sampling technique in clinical management, particularly when the index of suspicion remains high.[12-14] Current diagnostic guidelines indicate imaging, ascitic fluid analysis, and peritoneal biopsy for confirmation.[8,12-14]
Conclusions: Atypical tuberculosis presenting in the peritoneum creates a diagnostic challenge for clinicians, and advancing clinical awareness of this unique presentation will help in the timely intervention and treatment of this disease while also supporting diagnostic protocols to improve patient outcomes, particularly in low prevalence regions.