Lecture 11- Tuberculosis Flashcards
(19 cards)
Tuberculosis is?
Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis (MTB). Tuberculosis generally affects the lungs, but can also affect other parts of the body.
TB can cause puss in lungs, what does this look like on xray?
white fluffiness
Where is TB most prevalent
Developing countries
-Africa
TB sufferers in NZ are usually people who
were born overseas and migrate to NZ
Mycobacterium Tuberculosis strains?
M. tuberculosis (know this*)
M. bovis (cow TB)
M. africanum
M. ulcerans
two different classifications of mycobacteria?
1) TB
2) non-tuberculosis mycobacteria (NTM)
- rapid growing
- non rapid growing
Transmission of TB
Pulmonary route
-coughing, gets into alveoli, can float in dust (rare) therefore can be direct and indirect transmission.
Has to touch pulmonary alveoli macrophages.
-can also be drunk (cows milk)
LAM
causes TB to be eatin by WBC, keeps it alive and stops macrophage from signalling others
Commonly the IS doesn’t sufficiently clear all the TB infection… what often happens?
Granuloma ‘prison’ formed.
- Middle= necrotic muck
- outer macrophages that haven’t been allowed to die
- outermost CD4 lymphocytes telling macrophages what to do
Granuloma formed often in chronic diseases (if necrosis occurs then usually TB)
Latent TB infection
Most of the time infection is contained successfully by the granuloma.
Not always permanent
TB reactivation
Granuloma can fail, TB wakes up when there is interference -cancer -age -HIV -steroids -cancer
Extra pulmonary TB
TB in other places
-lymph glands
Miliary TB
TB is everywhere, blood, urine, lungs.
High risk of death
Samoa TB vs NZ TB
Samoan more common
Most common age for TB infection
Infection more common in children
How to diagnose TB
- suspicion
- collect sputum (look for TB)
- chest x-rays
- grow TB in lab
Stain to identify TB
due to mycobacteriums lipid rich wall they retain the stain and you cannot wash it out.
Is there any reason to treat latent TB
if they have rhematoid arthritis so the treatmnt they use (interfere with TNF-a) could reactivate TB
Mantoux problems
inject with TB
-after 72 hours if lump present IS reaction
