Tuberculosis

Question 1

Tuberculosis (TB) Etiology/ causes?

Answer 1

Inhalation of droplets containing Mycobacterium tuberculosis

Question 2

Primary TB Pathophysiology?

Answer 2

1. TB bacilli are phagocytosed by alveolar macrophages,
2. inducing a T-cell-mediated immune response.
3. Macrophages and T cells kill most of bacilli,
4. but a few residual bacilli lay dormant
   in the Ghon complex (primary TB)

Question 3

Secondary TB Pathophysiology?

Answer 3

Upon reinfection or immunosuppression, these organisms become activated

Question 4

Complications from TB?

Answer 4

1. TB may spread via lymphatics or blood and result in miliary TB
   (seeding of distal organs)
2. other extrapulmonary TB manifestations (meningitis and Pott disease of the spine).

Question 5

Primary TB gross fx?

Answer 5

1. Ghon complex (lesion in upper part of lower lobe that becomes calcified);
2. enlarged caseous hilar lymph nodes

Question 6

Secondary TB gross fx?

Answer 6

1. Tubercle formation (cavitary lesion) in lung apex or hilar lymph nodes;
2. caseating granuloma made of epithelioid cells, fibroblasts, and giant cells

Question 7

Primary TB clinical signs?

Answer 7

asymptomatic

Question 8

Secondary TB clinical signs?

Answer 8

constitutive symptoms:
fatigue, 
weight loss, 
fever, 
productive cough with hemoptysis

Question 9

TB Lab findings?

Answer 9

Positive Mantoux/PPD test,

calcified Ghon complex on CXR,

acid-fast bacilli in sputum and confirmed by culture

Question 10

TB Treatment?

Answer 10

Patient is first placed on a combination therapy of PIR for 2 months while tapering
down to RI for 4 more months

Question 11

What does Mantoux/PPD test do?

Answer 11

Indicates delayed hypersensitivity after primary TB infection