Tuberculosis

Question 1

Who gets TB in descending order?

Answer 1

Foreign born 
Aboriginal 
Inner city population
Incarcerated Individuals
Health care workers (less so)

Question 2

What happens if TB is inhaled?

Answer 2

• coughed out or non-specific immune system eliminates it –> (TB SKIN TEST NEGATIVE)
• progression to primary ACTIVE tuberculosis –>cough, fevers, weight loss –>contagious
• immune system walls it off so you get LATENT tuberculosis –> (Tuberculin skin test positive) –>
  You are not infectious to others in this stage.

Question 3

What is the pathogenesis of TB?

Answer 3

Macrophage engulfs organism –> presents antigen

CD4 cells release gamma interferon, TNF alpha and other cytokines (IL1,2,10) which mediate granuloma formation

Question 4

What is a granuloma?

Answer 4

consists of epitheloid cells or tissue macrophages surrounded by lymphocytes mediating the reaction

Question 5

T or F: most granulomas do not heal

Answer 5

F:

Most of these heal with fibrosis - 10% calcify

Question 6

Who usually gets sick with TB?

Answer 6

Immunocompromised people
HIV
Recent contacts or recent tuberculin skin test converters
Fibronodular CXR changes (bad X-rays)
Diabetes, Renal Disease, Malnourished, Silicosis, Head and Neck Cancers,

Question 7

How to diagnose latent Tb?

Answer 7

TST – purified protein derivative
Interferon Gamma Release Assays
–>Quantiferon Gold

Question 8

What is a negative TST score?

Answer 8

0-4 mm

Question 9

How to treat TB?

Answer 9

Isoniazid daily for 9 months
Second-line:
Rifampin for 4 months
Isoniazid and Rifampin for 4 months

Question 10

How to diagnose active TB?

Answer 10

Send samples for TB cultures:
Sputum
Induced Sputum
Bronchoscopy and Post Bronchoscopy Sputum

Question 11

What are symptoms of active TB?

Answer 11

cough > 3 weeks
fever
night sweats 
weight loss
hemoptysis

Question 12

What to expect on chest xray of TB?

Answer 12

Hilar or mediastinal lymphadenopathy
Infiltrate or consolidation - Opacification of airspaces within the lung parenchyma
Nodule with poorly defined margins
Pleural effusion

Question 13

Which is more sensitive for TB: induced sputum , spontaneous sputum, or a bronchoscopy?

Answer 13

Induced sputum equal to bronscopy, but spont. sputum inferior

Question 14

What are the major drug for TB?

Answer 14

INH = H
Rifampicin = R
Pyrazinamide = Z
Ethambutol = E
(Streptomycin)

2 months HRZE + 4 months HR

Question 15

T or F: Co-infection with TB drives HIV viral replication

Answer 15

T

Rapid progression to disease in the newly infected