Asthma Flashcards
3 features of asthma
Hypertrophy of airway wall
Increased mucous production
Inflammatory cell infilitration
Describe the process of pathogenesis of asthma
1) Allergens activates Th2 cells producting IL4,5 and other mediators
2) IL4 and 13 activate IgE
3) IgE, IL4, IL6, IL9 activates mast cells
4) Mast cells release mediators of inflammation
5) Mediators activate nerve endingsm make mucus, aurway wall oedema
What happens to peak flow, FEV1 and FEV1/ FVC ratio furing an attack
They all decrease
What happens to FEV1 after an attack is finished
Increases by >15% or by >200ml
What do flow volume loop show in asthma
Reduced expiratory flow
Why is gas exchange impaired in asthma
V/Q mismatch with plugged bronchi
What happens to compliance during asthma
It increases
How does regularly monitoring peak flow help diagnose asthma
if there is a 20% diural variation for 3 days a week for 2 weeks its asthma
What 4 things does airflow through the tubes depend on
Radius of tube
Viscocity of tube
Pressure differences across tube
Length of tube
How much should FEV1 increase by after 400microgram salbutamol via spacer
> 15% and 200ml
How much salbutamol is given via nebuliser
2.5micrograms
How much steroids are supposed to be adequate to increase FEV1 by 15%
30micrograms a day for a fortnight
What are some common allergens that trigger asthma
Dust
Grasses
Pollen
Fur
Name some common irritants that trigger asthma
SO2, NO2, O3, cigarrette smoke, hydrocarbons, rape pollen
Why does exercising sometimes trigger asthma attack
Increased ventilation
Leads to cooling
Leads to spasm
