TB Flashcards
population infected with TB
1/3 of the population
rate of new TB cases falling globally
TB description
chronic, granulomatous disease caused by the bacterium mycobacterium tuberculosis
TB caused by
Mycobacterium tuberculosis
mycobacterium tuberculosis
phagocytksed by macrophages an dis found in membrane bound particles known as phagosomes
infected phagosomes
does not mature to fuse with lysososomes/acidity
granuloma formation
body contains intracellular mycobacterium tuberculosis within macrophages
transmission of TB
aerosol transmission occurs from persons with infectious active TB disease
spread by droplet nulclei
droplets of TB
remain suspended for long periods
expelled when a person with infectious TB coughs, sneezes, speaks or sings
after environmental exposure
70% uninfected
30% infected
after infected with TB
5-10% primary tuberculosis
90-95% latent TB infection
after latent infection established
containment and persistence
a portion will develop reactivation disease
risk factors for developing reactivation disease
10% healthy adults
20% children <5 years
30% HIV+ patients
40% children <2 years
ghon complex
peripheral lesion and casiating lymph nodes
majority will heal lesion and remain asymptomatic, some will develop latent infection, some will develop progressive primary tuberculosis
reactivation of latent TB
secondary tuberculosis
secondary tuberculosis
localised caveating destructive lesions or progressive secondary TB
miliary Tb
massive haematogenous dissemination from progressive primary or secondary TB