TB Flashcards
Where should a patient with TB be admitted?
negative pressure isolation room
AIRBORNE ISOLATION
Where are the cavitations of TB seen & why?
in the upper lobe of the right lung
- because there is the most oxygen there due to low exchange there
What should be excluded in case of any cavitation or consolidation in the bases of both lungs?
septic emboli until proven otherwise
- usually from right sided endocarditis
What are the risk factors for TB?
- endemic country (india, pakistan, Saudi Arabia)
- jail
- IVDU
- smokers
- immunocompromised hosts
- HIV
What is the pathogenesis of TB?
airborne transmission -> droplet nuclei
- exposure to infected person -> inhalation -> alveolar macrophage (high IFN-y) -> hard shell & inactivates TB (latent TB) -> diminished immune system -> reactivation of TB (common in adults)
OR
- alveolar macrophage unable to inactivate TB -> primary infection (common in children)
How should u check for latent TB?
IFN-y assay
What is the risk of reactivation of TB?
- 5% in the first 2 years
- 10% in a lifetime
- 10% every year in HIV
What are the clinical features of pulmonary TB?
- constitutional symptoms
- chronic cough
- dyspnea
- hemoptysis
What are the clinical features of extra pulmonary TB?
- pleurisy
- meningitis
- peritonitis
- lymphadenitis (cervical cold abscess)
- pericarditis
- vertebral (Pott’s disease)
What investigations should be performed for pulmonary TB?
- CXR -> apical cavitation or any findings in HIV patients
- sputum AFB smear x3 with 8 hours in between
- sputum M. TB PCR
- sputum AFB culture (for 6 weeks)
What investigations should be done for extrapulmonary TB?
- AFB smear
- M. TB PCR
- AFB culture
What investigations have the highest sensitivity in diagnosis of TB?
1- AFB culture
2- M. tuberculosis PCR
3- AFB smear
What are the phases of treatment of TB?
INDUCTION PHASE (2 months)
- isoniazid + vit B6
- rifampin
- ethambutol
- pyarzinamide
CONTINUATION PHASE (4-7 months)
- isoniazid + vit B6
- rifampcin
SCREEN ALL TB PATIENTS FOR HIV
When can we discontinue airborne isolation?
when ALL are present
- 2 weeks of treatment
- 3 consecutive sputum AFB are negative (8 hours apart)
- improving respiratory symptoms
What are the side effects of TB drugs?
- isoniazide -> hepatotoxicity, neurotoxicity due to B6 deficiency
- Rifampcin -> hepatotoxicity, gastritis, orange discoloration of body fluids
- ethambutol -> LEAST hepatotoxicity, optic neuritis
- pyrazinamide -> MOST hepatotoxic, hyperuricemia (gout), arthritis
