Asthma Flashcards
What level of airflow obstruction differentiates between asthma and COPD?
> 15% is reversible in asthma, <15% of obstruction in COPD
Describe the aetiology of intrinsic asthma
Starts in middle aged, no trigger to be found
Describe the aetiollogy of extrinsic asthma
atopic individuals, positive skin prick test results, 90% of chilhood cancers and 50% of adult, often accomopained by eczema. Type 1 hypersensitivty reaction mediated by IgA
Name 2 genes associated with atopic individuals
ADAM33 - increases airway hyper responsiveness and airway remodelling
PHFF11 - increased IgE production
Describe the bronchial provocation test
Assesses for airway hyper responsivness - ask patient to inhale increasing amounts of histamine, in 20% of pop will produce transient airflow limitation
Describe the 3 characteristics of asthma
Airflow limitation (usually reversible)
airway hypersensitivity
Inflammation of the bronchi
Describe management and symptoms in step 1 asthma
Occasional symptoms > daily PRN bonchodilators (salbutamol)
Step 2 asthma
Symptoms more than 3 x a week
PEFR <80% predicted
Low dose inhaled corticosteroids (200-400ug, up to 800ug)
step 3 asthma
Severe sympatoms
PEFR 50-80% predictor
LABA (long acting B2 agonist)i.e. sertide is a combo LABA and corticosteroid
step 4 asthma
Severe symps not controlled by high dose corticosteroids
50-80% PEFR
Higher dose inhaled corticosteroid - up to 2000ug, consider a leukotriene receptor antagonist (e.g. monteleukast)
Step 5 asthma
Severe symptoms, deterioating
<50% predicted PEFR
Add prednisolone 40mg daily
Step 6 asthma
Detioarting despite pred, <30% predicted PEFR
admit to hospital
Describe how to manage a life-threatening asthma attack
Give magnesium sulphate 1.2-2g IV over 20 minutes
Give nebulized salbutamol every 15 minutes
Give ipratropium bromide every 4-6 hours
After attack give orally prednisolone for 5 days
