Tuberculosis Flashcards
Where is mycobacter tuberculosis found in the body when infected?
It is a large rod shaped bacteria that resides in the well aerated upper lobes of the lungs. Usually found within macrophages as it is intracellular parasite
What other bacteria can cause tuberculosis?
M. bovis and M. avium
How is tuberculosis transmitted?
It is transmitted through airbourne particles, there is about a 1/30 chance of transmission
What four things alter the chance of tuberculosis being passed on?
The susceptibility of the exposed person
The infectiousness of the person with TB
Enironmental factors (concentration of TB orgnaisms)
Proximity, Frequency and duration of the exposure
What is a latent TB infection?
2-8 weeks after initial infection macrophages form granulomas surrounding the TB
TB disease occurs when the immune system is no longer able to keep these bacteria from multiplying
How can you detect latent TB infection?
tuberculin skin testing or interferon-gamma release assay. Both not that specific
What is miliary TB?
When it spreads to the rest of the body but this is less common. Can include the CNS which causes meningitis
What symptoms should you suspect TB in?
Unexplained weight loss, anorexia, night sweats, cough or fever that lasts more than 3 weeks
How is active TB diagnosed?
With microscopy and culture of three sputum samples
Can also be done with imaging (CXR shows patchy inflitrates and cavitation)
How is active TB treated?
Managed with prolonged drugs and multiple courses of antibiotics (minimum 6 months)
What are the first line treatment drugs for TB?
isoniazid, rifampicin, ethambutol, and pyrazinamide
What are the two phases that treatment takes place in?
Initial phase is combination of the two drugs for 2 months
two drugs to which the organism is sensitive continued for 4 months
