Case Presentation: A 72-year-old man from Bangladesh, who immigrated to the U.S. 4 years ago, presented with ten days of constipation and progressively worsening abdominal pain. He reported no alcohol use, recent travel, known tuberculosis (TB) contact, IV drug use or incarceration history. The patient appeared frail and vital signs were within normal limits. His abdomen was tense, distended, and positive for shifting dullness. Laboratory parameters revealed normal liver and kidney functions, negative HIV and viral hepatitis serologies, negative IGRA TB test, normal CEA level, and elevated CA-125 of 307 u/ml (0-35 u/ml). Chest X-ray was unremarkable. CT abdomen and pelvis with contrast revealed abundant abdominal ascites with loculated components within the mesentery. 550 mL of yellow ascitic fluid was then drained via diagnostic paracentesis showing total RBCs of 250/mm3, WBCs of 1065/mm3 with 98% lymphocytes, adenosine deaminase of 40 U/L (0-9.5 U/L), SAAG <1.1 g/dl. Cytology was negative for malignant cells and peritoneal fluid acid fast stain and mycobacterial culture were negative as well. Endoscopy and colonoscopy were also negative for gastrointestinal pathology. Exploratory laparoscopy revealed diffuse miliary white plaques along all peritoneal and visceral surfaces. Peritoneal biopsy revealed granulomas with focal necrosis and rare acid-fast bacilli confirming the diagnosis of peritoneal tuberculosis. Patient was started on rifampin, isoniazid, pyrazinamide, and ethambutol immediately after biopsy. Symptoms improved days after treatment and in a two-month follow-up visit, ascites and abdominal distention significantly improved.
Discussion: Abdominal TB represents 5% of all cases of TB worldwide (1). Any intra-abdominal organs can be involved, but most commonly affects the peritoneum, intestine and liver. Although uncommon in the US, CDC reported in 2017 that out of 1,887 cases of extrapulmonary TB, 6.2% were peritoneal (2). Peritoneal TB commonly occurs after reactivation of latent TB in the peritoneum; however, it also occurs in patient with active pulmonary TB or miliary TB via direct hematogenous spread to the peritoneum (3). Clinical diagnosis is often difficult given the non-specific presentation, with ascites and abdominal pain being the most common manifestations (93% and 73% respectively) (4). However, diagnosis needs to be confirmed by demonstrating mycobacterium TB in peritoneal fluid or by peritoneal biopsy (5). Peritoneal TB poses a diagnostic challenge and may require extensive work up to confirm it. A high index of suspicion is required, especially in patients with risk factors, such as HIV patients or immigrants from highly endemic regions. Accurate and timely diagnosis is crucial for early initiation of the appropriate treatment thus prevention of serious complications. The approach to antituberculous therapy for peritoneal TB will be the same as that for pulmonary TB (6).
Conclusions: It is important to consider tuberculosis as an etiology of ascites even in patients without history of exposure or prior infection. Ascitic fluid ADA is helpful in making the diagnosis but peritoneal biopsy is often required for definitive diagnosis.