adult asthma features Flashcards
(43 cards)
defining features
increased responsiveness of trachea and bronchi to various stimuli
manifested by widespread narrowing of airways that changes in severity either spontaneously or as a result of therapy
airway inflammation is mediated by the immune system
symptoms of asthma
SOB Wheeze (check severity) cough (paroxysmal, usually dry), sputum is occasional chest tightness (pain) diurnal variability episodic atopy
signs of asthma
wheeze on auscultation eczema obstructed spirometry PEF changes response to treatment
epidemiology of asthma in children
10-15%m>f
epidemiology of asthma in adults
5-10%
f>m
how many deaths are caused by asthma each year
1000
2/3 are preventable
proven risk factors of asthma
genetic
occupation
smoking
genetic risk factor
atopy
strongest risk factor: personal, familial atopic tendency
maternal atopy is the main influencer (3x father)
2 groups of genetic associations: immune response genes (IL-4, IL-5, IgE); airway genes (ADAM33)
disease clustering in families may be linked to environmental exposure
define atopy
inherited tendency to IgE response to allergens
asthma, eczema, hayfever and food allergy
occupation risk factor
10-15% of adult onset asthma
interactions w/ smoking and atopy
high risk jobs: bakers, welders, lab workers w/ animals, working w/ shellfish etc.
smoking risk factor
maternal smoking during pregnancy: reduced FEV1, increased wheezy illness, increased airway responsiveness, increased asthma and severity
grandmother effect - epigenetic modification of oocytes
what is the grandmother effect
link between smoking and OR asthma age 5
mother smoked - 1.5
maternal grandmother smoked - 2.1
mother and maternal grandmother smoked - 2.6
possible risk factors of asthma
obesity diet reduced exposure to microbes indoor pollution environmental allergens
obesity risk factor
BMI +vely associated w/ asthma, wheezing, airway hyperreactivity
diet risk factor
reduced antioxidant, n-3 polyunsaturated FA, increased n-6 polyunsaturated FA, increased/decreased vit D has associations w/:
- reduced FEV1
- increased wheeze
- increased asthma
- reduced wheeze and asthma; increased oily fish consumption and butter
supplementation in established disease is ineffective
reduced exposure to microbes risk factor
includes microbial products (endotoxin, glucans, extra capsular polysaccharide)
children born on farms are less likely to develop asthma
microbial diversity appears to be important in reducing risk of asthma and allergy
indoor pollution (chemical household products) risk factor
volatile organic compounds
formaldehyde
fragrances
cleaners at increased risk (OR 1.97)
people who use sprays weekly: 1.49x more likely to be asthmatic
people who use sprays 4x/wk: 2.11x more likely to be asthmatic
mothers who use sprays during pregnancy: children increased asthma
environmental allergens risk factor
house dust mite cats grass pollen exposure doesn't initiate atopy/asthma factors associated w/ affluence increase the likelihood of sensitisation to local allergens
house dust mites
warm, humid houses europe and coastal australia 200x own weight in droppings allergen is a protease in droppings exposure - pillows and bed
cats
universal exposure to allergen
evidence to show exposure may be protective
once sensitised, exposure is a major problem
clinical aspects
try to differentiate from other causes of wheeze
- localised airway obstruction, inspiratory stridor, tumour, foreign body
- generalised airflow obstruction: asthma (reversible AFO), COPD (irreversible AFO), bronchiectasis, bronchiolitis, CF
clinical Hx
symptoms evidence of variable symptoms: triggers and diurnal variation/weekly variation (occupational)/annual variation (environmental) PMH drugs FMH - atopic disease SH
symptom triggers
exercise cold air smoke perfume URTIs pets tree and grass pollen food aspirin
past medical Hx
childhood asthma
bronchitis
eczema
hay fever
