Management of Pulmonary Tuberculosis in 2025: An Update for the Respirologist

Abstract

Despite being a curable illness, tuberculosis (TB) remains the most common cause of death from an infectious agent, with a reported 10 million infections and 1.25 million TB-related deaths reported globally in 2023. In Canada, the incidence of TB has remained at approximately 5.1 per 100,000 for many years. However, foreign born and Indigenous populations are disproportionately affected by TB, with the Inuit population experiencing the highest TB incidence in Canada, at a reported rate of 70 per 100,000 in 2020.³ Drug-resistant TB is reported in less than 10% of TB isolates in Canada, the majority being isoniazid mono-resistant. Multidrug-resistant TB (MDR-TB), defined as resistance to both isoniazid (INH) and rifampin (RIF), is detected in fewer than 4% of drug-resistant TB isolates in Canada.

TB is caused by the Mycobacterium tuberculosis (MTB) bacillus, and is spread when people infected with TB aerosolize the bacteria through coughing, laughing, singing, or talking. Following initial infection, the risk of developing active TB disease is greatest in the first 2 years, then decreases significantly, with an estimated lifetime risk of approximately 10%. In addition to several host factors, the risk of TB reactivation increases in the setting of immune suppression, including HIV infection, malignancy, organ or bone marrow transplant, and immunosuppressive treatments such as prednisone and tumour necrosis factor (TNF)-alpha therapy. Prior to initiating treatments that may increase the risk of reactivation, latent TB infection should be considered and appropriate investigations performed.