Reactivation of Pulmonary Tuberculosis During Treatment of Chronic Myelomonocytic Leukemia

A 76-year-old woman from a tuberculosis (TB) endemic region with chronic myelomonocytic leukemia (CMML) on Azacitidine presented with a non-productive cough. A CT scan of the chest revealed a lobulated opacity in the right upper lobe and antibiotic therapy was initiated for a potential bacterial pneumonia. However, a high suspicion for pulmonary TB remained given her nation of origin, immunosuppression, and imaging findings. Three sputum and bronchoalveolar lavage (BAL) acid-fast bacilli (AFB) smears with PCR testing for Mycobacterium tuberculosis were negative, as were examinations for other potential fungal or bacterial etiologies of the patient’s symptoms and imaging findings. While awaiting final TB culture results from BAL, her CMML underwent a transformation to acute myeloid leukemia (AML). Given the urgent need for initiation of chemotherapy, empiric treatment for TB was commenced while awaiting the final TB culture. Within 48-hours of initiating therapy for TB, the patient’s fevers subsided. One week after discharge our team was notified of a positive M. tuberculosis culture from BAL. We suspect that our patient had a latent TB infection which reactivated due to her CMML. This case highlights the importance of maintaining a high clinical suspicion for TB in high-risk patients, even in the case of initially negative laboratory examinations. Further, it demonstrates the importance of screening and treating latent TB in patients with leukemias.