POM 14 - Patient with tuberculosis Flashcards
what are the 2 main classifications of mycobacteria
TB
non tuberculous mycobacteria
what are the 3 types of non tuberculous mycobacteria
rapid growing
non rapid growing
other
what disease can non tuberculous mycobacteria cause
leprosy
how does TB enter the body
breathing in TB particle and TB lands in nose or lungs
TB will cause disease if it lands in what anatomy - why is this
if it lands in lungs
TB wants to be eaten by lung macrophage
what is a lung macrophage called
pulmonary alveolar macrophage
what happens when TB is phagocytosed by lung macrophage
LAM on surface of TB binds to complement receptor of pulmonary macrophage
LAM makes TB preferentially phagocytosed by pulmonary macrophages
what happens when lysosomes attempt to kill TB
TB resists
how does TB survive intracellularly
changes cellular function by stopping apoptosis and induces macrophage to stay alive
what does the immune system do once the TB survives in the macrophages
takes antigen producing cells and macrophages taken antigen to the lymph nodes and find helper T cells which recognize Tb and recruits other cell
overall TB is carried to the local lymph nodes
how does the immune system ‘quarantine’ the bacteria infected cells
via a granuloma
puts uninfected macrophages around infected cell - forms ball around gooey necrotic centre
when the granuloma has been put in place around the TB cells how is the granuloma sustained
helper T cells form sphere around outside to continuously bombard macrophage jail with signals to keep their integrity and keep them alive/robust
what can happen with latent TB infections
can be reactivated if something upsets the immune system and the granuloma can fall apart to spread TB
what is the primary cytokine the helper T cells use to bombard the granuloma
tumor necrosis factor alpha (TNFa)
what is miliary TB
TB which has disseminated everywhere
what are the 7 outcomes of primary TB infection
focus
pleural
cavitation
enlarged nodes
TB bronchopneumonia
pericardial disease
miliary
what is ghons focus outcome in primary TB infection
calcium in lungs/lymph node
what is pleural outcome in primary TB infection
Tb on periphery of lungs and alveoli bursts
what is cavitation outcome in primary TB infection
abscess where the granuloma eats away at the lung tissue
a variant of pulmonary Tb
what is enlarged nodes outcome in primary TB infection
enlarged lymph nodes which squashes the airways
what is pericardial disease outcome in primary TB infection
TB sitting next to heart and erodes through heart and explodes causing infection in pericardium
this infection then goes onto squish the heart and impede heart function
how is TB transmitted
droplet and airborne transmissions
cutaneous and gastrointestinal tract from drinking milk used to be as well but not anymore
how is TB diagnosed - 4 ways
chest xray - but is non specific
sputum specimens via acid fast bascillus
TB PCR to find DNA of TB
TB culture
how is the ziehl neelsen stain performed for TB - 4 steps
- smear specimen on slide
- apply carbo-fuchsin stain
- apply heat
- wash with HCl in ethanol
