Mycobacterial Infections Flashcards
What are the bacteria that cause typical TB? (7) Which two are the main organisms that cause TB?
**M. TB** M. Bovis **M. Africanum** M. Microti M. Canetti M. Caprae M. Pinnipedii
What is atypical TB?
Non-TB mycobacteria that grow slowly
What are the two bacteria that comprise the MAC complex?
M. Avium
M. intracellulare
What is the natural source of non-TB bacteria?
Water sources
Progressive lung disease with non-TB bacteria usually occurs in whom?
In patients with underlying bronchiectasis or COPD
What are the two distinct forms of MAC?
Fibrocavitary disease
Fibronodular disease
What is the fibrocavitary disease seen with the MAC complex infection? In whom is it seen? How does it appear on CXR?
TB-like disease with Cavitary lesions. Seen in older male smokers with COPD.
Usually upper lobe predominance on x-ray.
What is the fibronodular disease seen with the MAC complex infection? In whom is it seen? How does it appear on CXR?
TB like disease seen in nonsmoking women over 50 yo, and without underlying lung disease
Diffuse interstitial infiltrates and bronchiectasis
What is the natural source of M. Kansasii? How does this present?
Water (tap water in endemic cities)
TB cavitary lesions with chest pain, cough, hemoptysis and night sweats
true or false: the drugs used to treat atypical TB are the same as typical TB, making culturing them clinically insignificant
false–different drugs
Who usually gets fast growing atypical TB infections? Are cavitations more or less common?
White, middle aged females
Usually infiltrates–rarely cavitary lesions
True or false: there is no other test besides a culture to differentiate TB from non TB
True
True and false: the ssx of atypical TB are the same as usual TB
True
What is the treatment for atypical TB (3)? How long?
Macrolide + rifampin + ethambutol
12-18 months
What is the most common infectious cause of death worldwide? #2?
1 = HIV 2 = TB
What fraction of the world’s population is infected with TB?
1/3
Where in the world are the highest rates of infection with TB?
Sub-saharan africa
Islands of southeast Asia
What are the three possible consequences of TB droplet inhalation? What is the most common?
- Immediately cleared without issue
- immediate onset of disease
- Latent infection with reactivation years later**
True or false: most patients with exposure to TB clear it without issue
True
True or false: in patients who are infected with TB, most of the time is is contained
true
What is primary TB?
When initial infection with TB is not controlled by local defenses and spreads to regional lymph nodes
What is a Ghon complex?
Localized Lymphadenopathy in the lung that is caused by tuberculosis.The lesions consist of a calcified focus of infection and an associated lymph node
Why are the cavitary lesions with TB usually seen in the apices of the lung?
Most aerated area of the lung
What happens with TB infection if the cell mediated immunity is inadequate?
Hematogenous spread, causing active disease. Becomes infectious.