Video - Tuberculosis: Pathology review

Tuberculosis (TB) is a chronic infectious disease caused by the bacterium Mycobacterium tuberculosis. The pathophysiology of TB involves a complex interplay between the bacterium and the immune system of the host. When a person inhales air contaminated with M. tuberculosis, the bacteria can enter the lungs and infect the alveolar macrophages, which are the immune cells responsible for clearing foreign particles from the lungs. In most cases, the immune system can contain the infection and prevent the development of active TB disease.

However, in some cases, the bacteria can evade the immune system and establish a latent infection, in which the bacteria remain dormant in the body for years or even decades. Latent TB infection is not contagious and does not cause symptoms, but it can progress to active TB disease if the immune system becomes weakened, such as in people with HIV/AIDS, malnutrition, or other conditions that compromise the immune system.

In active TB disease, the bacteria can multiply and spread throughout the body, causing symptoms such as cough, fever, weight loss, and night sweats. The infection can also damage the lungs and other organs, leading to complications such as pleural effusion, pneumonia, and meningitis.