Clinical meaning
Tuberculosis is caused by Mycobacterium tuberculosis, an acid-fast bacillus transmitted through airborne droplet nuclei. When inhaled, the bacteria reach the alveoli where macrophages attempt to contain them, forming granulomas (tubercles). In most people (90-95%), the immune system contains the infection in a latent state. Reactivation occurs when immunity weakens, allowing bacteria to multiply and cause active disease with cavitary lesions typically in the upper lobes.
Exam relevance
Risk factors: - Close contact with active TB case - HIV/AIDS - Immigration from TB-endemic countries - Homelessness or incarceration - Immunosuppressive therapy - Malnutrition - Substance abuse - Healthcare workers
Diagnostics: - Monitor temperature and report fever - Observe for chronic cough, night sweats, and weight loss - Collect sputum specimens as ordered (early morning × 3 consecutive days) - Monitor adherence to medication regimen - Report any adverse effects of TB medications (nausea, jaundice, visual changes)