Primary pulmonary tuberculosis

Primary pulmonary tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis that primarily affects the lungs. It represents the initial infection in individuals who have not previously been exposed to the organism. Upon inhalation of airborne droplets containing the bacteria, the organism establishes a primary focus of infection (Ghon focus) in the lung parenchyma, often accompanied by involvement of the regional hilar or mediastinal lymph nodes, forming what is known as the Ghon complex. In many cases, the immune system contains the infection, and the disease remains latent. However, in some individuals—particularly young children, immunocompromised persons, and those with certain genetic susceptibilities—the infection can progress to active disease. Key symptoms of active primary pulmonary tuberculosis include persistent cough (often lasting more than two weeks), fever, night sweats, weight loss, fatigue, and occasionally hemoptysis (coughing up blood). Chest pain and shortness of breath may also occur. In children, primary TB may present with hilar lymphadenopathy, which can cause airway compression. The disease can spread beyond the lungs to affect other body systems including the lymphatic system, bones, central nervous system, and kidneys (extrapulmonary tuberculosis), particularly in immunocompromised individuals. Susceptibility to tuberculosis has a multifactorial basis, involving both environmental exposure and host genetic factors. Several genetic loci have been implicated in susceptibility to mycobacterial infections, including variants in genes involved in the immune response such as those in the interferon-gamma pathway (e.g., IFNGR1, IFNGR2, IL12B, IL12RB1, STAT1) and other immune-related genes. Mendelian susceptibility to mycobacterial disease (MSMD) represents a group of rare genetic conditions that predispose individuals to severe mycobacterial infections. Treatment of active pulmonary tuberculosis involves a standardized multi-drug regimen typically consisting of isoniazid, rifampicin, pyrazinamide, and ethambutol for an initial intensive phase of two months, followed by a continuation phase of isoniazid and rifampicin for four months. Drug-resistant forms require longer and more complex treatment regimens. BCG vaccination provides partial protection, particularly against severe forms of TB in children.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Primary pulmonary tuberculosis