Case Presentation: A 40-year-old immigrant from Bangladesh with a history of uveitis presented to the emergency department for evaluation of abdominal pain. He first developed fevers 10 days prior to admission, when he was visiting his hospitalized mother in Bangladesh. He subsequently noticed increased abdominal girth and returned to the United States for additional evaluation. Of note, his uveitis was treated with adalimumab for the past 2 years. He had a negative QuantiFERON-TB Gold In-Tube (QFT-GIT) test prior to initiating treatment. Upon admission, ultrasound confirmed ascites but a normal liver. Paracentesis revealed 4100 RBC/uL, 5600 WBC/uL (47% lymphocytes), protein of 6.1g/dL, LDH of 868 U/L and adenosine deaminase (ADA) of 6.7 U/L. The SAAG was <1.1. Preliminary ascitic fluid cultures were negative. Tuberculin Skin Test (TST) and QFT-GIT were negative. Given the high clinical suspicion for active tuberculosis (TB) infection, the patient underwent exploratory laparoscopy. He was found to have many peritoneal tubercules. He was started on antituberculosis treatment and discharged home. One month later, the ascitic fluid cultures grew Mycobacterium tuberculosis.

Discussion: This is a case of active peritoneal TB infection in a man treated with an anti-tumor necrosis factor alpha (anti-TNF) monoclonal antibody. Screening for active TB and latent TB infection (LTBI) is mandatory prior to the initiation of treatment with anti-TNF drugs. However, there is no consensus on how patients should be monitored for active TB infection once started on an anti-TNF drug. Clinical manifestation of TB in patients on biologic agents if often atypical and extrapulmonary, placing them at risk for delayed diagnosis and disseminated disease. The sensitivity of QFT-GIT detecting LTBI in immunocompetent adults is 80-92%. That sensitivity decreases in active TB and immunocompromised hosts. In differentiating between TB and non-TB etiologies of ascites, fluid analysis, including ADA, can be helpful. However, the gold standard for diagnosis remains culture of ascitic fluid and/or peritoneal biopsy via laparoscopy.

Conclusions: Patients treated with anti-TNF drugs are at increased risk for primary and reactivation TB infection but more likely to have a false negative screening test result. Clinicians must maintain a high index of suspicion as such patients often present atypically.