Tuberculosis (TB)

What causes TB, and how does it spread?

Mycobacterium tuberculosis; airborne transmission.

How does the body contain TB?

Immune cells form granulomas/tubercles; caseous necrosis is cheese-like tissue death.

What are a Ghon focus and Ranke complex?

Ghon: primary lung lesion. Ranke: calcified lesion plus involved lymph nodes.

How do latent and active TB differ?

Latent: no symptoms, not infectious. Active: symptomatic and may be contagious.

What symptoms suggest active pulmonary TB?

Chronic cough, sputum/hemoptysis, weight loss, anorexia, low fever, night sweats.

How is TB evaluated?

PPD/IGRA, chest X-ray, sputum acid-fast testing/culture, and nucleic acid tests.

What does a positive PPD mean?

TB immune sensitization; it does not independently confirm active disease.

What does Xpert MTB/RIF identify?

TB genetic material and rifampicin resistance.

What are the main TB treatments and precautions?

Isoniazid, rifampicin, pyrazinamide, ethambutol; prolonged therapy and airborne isolation for contagious pulmonary TB.

What is multidrug-resistant TB?

TB resistant to at least isoniazid and rifampicin.