Asthma clinical features adults and children Flashcards
what characterises asthma?
- increased responsiveness of the trachea and bronchi to various stimuli and manifested by a
- widespread narrowing of airways that
- changes in severity either spontaneously or as a result of therapy
what 2 things does airway inflammation mediated by the immune system cause?
- widespread narrowing of airways
- increased airway reactivity (spontaneous airway narrowing or stimuli induced airway narrowing)
what is the prevalence of asthma in children? which gender is most affected?
10-15%, M>F
what is the prevalence of asthma in adults? which gender is most affected?
5-10%; F>M
what is the first proven risk factor for asthma?
genetics; atopy-
- inherited tendency to IgE response to allergens
- asthma, eczema, hayfever, food allergy
- markers, skin prick tests, IgE
which atopy is most influential? maternal or paternal?
maternal is x3 more influential than paternal
which genes are involved?
- immune response genes (IL4, IL5, IgE)
- airway genes (ADAM33)
what is the second proven risk factor for asthma?
occupation
how much of the asthma of adult onset does occupation account for? what factors does it interact with?
10-15% of adult onset asthma, interactions with smoking and atopy
what is the third proven risk factor for asthma?
smoking (including maternal smoking and smoking from grandmother)
what causes does maternal smoking have? (without necessarily going to asthma)
decreased FEV1 and increased wheezy illness, airway responsiveness, asthma, severity
how might maternal smoking affect the baby?
mouse work suggests epigenetic modification of ovocytes
what is the third proven risk factor for asthma?
obesity
what is a high BMI associated with?
asthma, wheezing, airway hyperactivity
what is the fourth proven risk factor for asthma?
diet
what diet are associated with increased risk of asthma?
lack of antioxidants, n-3 polyunsaturated fatty acids, too many ,-6 polyunsaturated fatty acids, variations in vitamin D intake
what diet is decreased FEV1 associated with?
lack of vitamin E, C, D and beta-carotene
what diet is increased wheeze associated with?
lack of vitamin E, C, lack of fruit and margarine
what diet is increased asthma associated with?
lack of selenium, D, fast food and margarine
what diet is decreased wheeze & asthma associated with?
increase of oily fish consumption and butter
is supplementation in established disease effective?
no, changing diet is a preventive measure
what is the fifth proven risk factor for asthma?
reduced exposure to microbes/ microbial products (children born on farms less likely to develop asthma)
is microbial diversity important in reducing the risk of asthma and allergy?
yes
what is the sixth proven risk factor for asthma?
indoor pollution: chemical household products (volatile organic compounds, formaldehyde, fragrances)
what are the commonest environment allergens and causes of atopy/ asthma?
house dust mite, cat, grass pollen
what is the particularity of cat allergen exposure?
evidence to show exposure maybe protective
what could be the other causes of wheeze?
localised airway obstruction, inspiratory stridor, tumour, foreign body
what could be the cause of generalised airflow obstruction?
asthma (reversible AFO), COPD (irreversible AFO), bronchiectasis, bronchiolitis, cystic fibrosis
what is the typical history for asthma?
wheeze, SOB (dyspnoea), chest tightness, cough, paroxysmal cough, usually dry, occasional sputum
what could trigger a variable symptom?
exercise, cold air, smoke, perfume, URTIs, pets, tree, grass pollen, food, aspirin, daily variation (nocturnal/ early morning), weekly variation (occupation, better at weekends & holidays?), annual variation (environmental allergens)
how do you exclude COPD as a diagnosis?
gas trapping: increased residual volume and total lung capacity, RV/ TCL > 30%
in what cases could there be no reversibility?
severe brochoconstriction or no bronchoconstriction
how do you check for atopic status?
skin prick testing, total and specific IgE, eosinophilia (full blood count)
how do you check for variability of airflow obstruction?
peak flow charts
