Miliary Tuberculosis in a Crohn's Disease Patient: The Risk beyond the Screening.

Tumor necrosis factor alpha (TNFα) antagonist is recognized as an effective treatment to achieve clinical remission and healing mucosal in patients with moderate to severe active Crohn's disease. Considering that it plays a central role in immune-mediated modulation, there are some obvious concerns about its long-term safety. There is evidence that it may increase the risk of opportunistic infections such as tuberculosis, particularly reactivation of previous latent infection. Due to the global high incidence of tuberculosis and its frequent severity in immunocompromised patients, the exclusion of latent infection is currently part of the screening prior to anti-TNFα therapy. Only a few cases of life-threatening disseminated tuberculosis have been reported in immunocompromised patients probably related to widespread use of higher-accuracy screening tests, such as interferon-γ release assays. However, despite negative screening, the risk of active tuberculosis infection remains during treatment. In that instance, tuberculosis infection becomes considerably more difficult to diagnose due to its altered pattern presentation (extrapulmonary and disseminated infection) and is harder to treat because of the high rate of resistance and its associated relevant morbidity and mortality. We report an enigmatic case of a miliary tuberculosis despite negative latent infection screening, using interferon-γ release assays, in a Crohn's disease patient undergoing treatment with infliximab and azathioprine, focusing on the screening and diagnostic and therapeutic challenge. This case enhances the awareness of anti-TNFα therapy management and the need for strategies to diagnose and treat tuberculosis in this context.