Asthma Flashcards
state the normal FEV1/FVC
70% of lung volume in first second.
Describe the definition of asthma
Airflow obstruction due to narrowing of airways + worsened by inflammation ( increases mucous)
- chronic inflammatory disease that involves overreactive constriction of bronchial SM
- REVERSIBLE airflow limitiation
State the risk factors for asthma - Genetic
- Inherited tendency to IgE response to allegens ( asthma, eczema, hayfever, food allergy
- genetic ( maternal atopy most influential 3x father)
- Genetic associations: (1)Immune response genes ( I-4, IL-5, IgE)
(2) Airway genes; ADAM33
State the proven risk factors for asthma
Genetic, occupation, smoking,
State the possible risk factors for asthma
Obesity, diet, exposure, indoor/outdoor pollution, pets
State risks for asthma - smoking
-Maternal smoking during pregnancy
State possible risk factors for asthma - diet
FEV1 decreases: -decrease vitamin E, C, D, B-carotene
Increase wheeziness: -decreases vitamin E & C, fruit, margarine
Increase asthma:
-decreases selenium, fast food, margarine
Decreases wheeze & asthma:
-Increases oily fish consumption, butter
State the possible risk factors - exposure
- Reduced exposure to microbes/microbrial products may cause asthma
- Children born on farms are less likely to develop asthma.
- possible exposure to endotoxins, glucans, extracapsular poysaccharide
State the possible risk factors for asthma - indoor pollution
- chemical household products
- voltatile organic compounds, formaldehyde, fragrances.
- mothers using sprays during pregnancy more likely to have asthmatic children. Cleaners also have a high risk
State the environmental allergens and atopy/asthma
House dust mite ( protease in droppings) found in pillows/bed
Cats, grass pollen(timothy grass)
-these exposures will increase the liklihood of sensitisation to local allergens
Other causes of wheeze
-localised airway obstruction: inspiratory stridor tumour, foreign body
- Generaised airflow obstruction:
- asthma ( reversible AFO)
- COPD ( irreversibe AFO)
- Bronchiectasis
- Bronchiolitis
- Cystic fibrosis
State the symptoms of asthma
- wheeze
- History
- shortness of breath (dysnoea), severity
- chest tightness ( pain)
- cough, paroxsyma(usually dry)
- sputum ( occasional)
State the evidence of variable symptoms
Triggers: excercise, cold air, smoke, perfume, URTI’s, pets, tree, grass pollen, food, aspirin
Daily variation ( noctornu/morning) Weekly variation ( occupation, better at weekends?) Annual variation ( environmental allergens)
Pathphysiology of asthma
- Type 1 hypersensitivity reaction
- IgE production when exposed to allergens
- IgE binds and activates mast cells, widespread airway narrowing + excess mucous production = airflow limitation
What symptoms will dismiss the symptoms of asthma?
Finger clubbing, cervical lymphadenopathy, stridor, asymmetric expansion, dull percussion note ( lobar collapse/effusion)
-Crepitations ( bronchiectasis, CF, alveolitis, LVF)
