Recall that two different conditions may occur when Mycobacterium tuberculosis bacteria invade the human body:
Active tuberculosis disease and latent tuberculosis infection.
In active TB, infection occurs when an individual inhales droplet nuclei containing M. tuberculosis bacteria. The bacteria reside intracellularly within the macrophages, and the immune system cannot keep them in check. Alveolar macrophages destroy most, but some may multiply intracellularly and are released alive, causing uncontrolled spread and active disease.
Symptoms: Unexplained weight loss, loss of appetite, night sweats, fever, fatigue, chills, coughing for >3 weeks, hemoptysis (coughing up blood), chest pain.
Lab and radiology results: Positive TB skin or blood test, may have an abnormal chest x-ray, may have positive (sputum) acid-fast bacilli (AFB) smear or culture.
