GINA Flashcards
4 asthma phenotypes
- allergic asthma
- non-allergic asthma
- asthma w persistent airflow limitation
- asthma w obesity
characteristics 1. allergic asthma
- childhood onset;
- PMH/FHx eg eczema, allergic rhinitis;
- induced sputum: eosinophilic ariway inflam
- respond well to ICS
characteristics 2. non-allergic asthma
- less short term response to ICS
- sputum profile: paucigranulocytic/neurotph/eosino
characteristics 3. asthma w persistent airflow limitation
airway remodelling in chronic asthma; irreversible airflow limitation
characteristics 4. asthma w obesity
little eosinoph inflam; obese pt w resp symp
4 Patterns of respiratory symptoms suggestive of asthma
- > 1 : wheeze, SOB, cough +/- chest tightness
- at night/early morning
- vary over time & intensity (Reversible)
- symptoms triggered by infection/allergen/exercise etc
5 Symptoms that make asthma diagnosis less likely
- exercise induced noisy inspiration
- chest pain
- SOB w dizziness/lightheadedness/paraesthesia
- isolated cough
- chronic sputum prdn
Diagnostic criteria of asthma in persons > 5 yr old
- pattern respiratory symptom
- documented expiratory airflow limitation AND
- documented excessive variability in lung function
What is documented expiratory airflow limitation?
FEV1 reduced– so FEV1/FVC reduced
normal adult >0.75-0.8
normal child>0.9
what is documented excessive variability in lung function?
positive bronchodilator reversibility test: 15 min after 200-400mcg salbutamol
- increase FEV1 >12% or >200ml from baseline
*withhold bronchodilator: SABA ≥4; BD LABA 24h; OM LABA 36hr
which test is more reliable in assessing variability in lung function?
FEV1 in spirometry > Peak expiratory flow
when should variability in lung function be assessed?
- at diagnosis/ before treatment started as otherwise lung function will improve
- after 3-6 tx
- every 1-2 yr after exacerbation
how to diagnose asthma in pt already on controller treatment
x
tests to exclude asthma
bronchial provocation test
eg inhaled methacholine– negative excludes asthma
but +ve cannot diagnose asthma
pt already on controller treatment– steps in confirming diagnosis
x box1-3 pg 26,27
when to consider differential diagnosis in asthma
normal/near normal FEV1 w frequent resp symptoms
in elderly workup of asthma
- consider CHF – sob at night/exertion – do ECG, CXR BNP, echo TRO
- hx of smoking– consider COPD
in workup of occupational asthma
- ask if symptoms improve when away from work
PEF monitoring at and away from work