Chronic Asthma - Adults Flashcards
What is asthma?
An increased responsiveness of trachea & bronchi to stimuli, changes in severity spontaneously or as a response to therapy
Causes inflammation and smooth muscle contraction causing narrowing of airways that makes expiration difficult
What else does inflammation do to the airways?
Increases their irritability causing them to narrow easier and more spontaneously
What does it mean that asthma is diurnal?
Worse during the day than in evening/night
Aetiology of asthma? What can cause worsening?
Genetic Environmental Obestiy and diet Cold air and exercise Occupational
What is the genetic aspects, What genes are suspected to be involved?
Immune gene - IL-4, IL-5 and IgE
Airways - ADAM33
Atopy related - a group of family disorders that are caused by increased responsiveness of IgE
What are some enviromental aspects?
Maternal smoking
Allergen exposure - induced IgE response (house mites, dust, pets)
Why does obesity and diet affect asthma?
High BMI is associated with asthma, obesity is also pro-inflammatory
Diet - increased intake of fresh fruit/veg gives protective antioxidants. No evidence that supplements help asthma though once you have it
What is exercise driven asthma caused by?
When does the wheeze occur when exercising/inhaling cold air?
Likey by a relase of prostoglandins, leukotrines and histamine from mast cells
Wheeze usually happens after exercise or inhalation of cold air
What are the 2 types of occupational exposure and whats it the difference?
Low molecular weight - non IgE
High molecular weight - IgE
Symptoms of asthma?
Wheeze
Dyspnoea
Chest pain
Cough - dry, nocturnal and paroxysmal
What is the problem with going off these symptoms alone?
Not very specific and cover a wide range of respiratory diseases
What should be focused on in a history?
Onset
Varitaion - daily, weekly, annually (chronic, occupational, seasonal allergies)
Exercise tolerance
Disturbed sleep
History of atopic disease - personal and family
Pets, new pillow, carpets
If already on inhalers
If used other drugs such as NSAIDS or beta blockers
What can be found in an examination and are they helpful?
Hyperexpanded chest
Polyphoic wheeze
Not really that helpful
What are some signs that show it might NOT be asthma?
Clubbing
Inspiratory stridor rather than a expiratory wheeze
Crepitations
What investigation should be done first? What levels show abnormality?
Spirometry
FEV1:FVC - <70%
FEV1 - <80%
If spirometry if abnormal what follow up test should be done?
A full pulmonary function test to look for COPD or other caused of obstuction
What is involved in a full pulmonary function test
Helium dilation - tests lung volume and capacity
Co gas transfer - shows gas exchange in Hb
What test should be done after a full pulmonary test?
If asthma symptoms are reversible with B2 agonists and ICS - seperates it from COPD
What should be done if spirometry came back normal, but asthma is still suspected?
Peak flow test programme, 2x daily
AFO has variation, might catch it with this
OR
Provoke the bronchus to react via exercise
OR
NO exhalation - measure of inflammation and index of steroid response
What should be done if occupation asthma is suspected?
Peak flow test - 2x hourly for 5 days with 2 pairs of exposed and 2 pairs of not exposed reading to compare to
What other useful investigations can be done?
CxR - look for hyperinflated lungs
Skin prick or total/specific IgE count - look for atopy
FBC for eosinphills (sputum eosinphill count may be better)
What is some non-pharmalogical aspects to managing asthma?
Action plans Weight loss Stop smoking Change jobs Avoid allergens
Bronchial thermoplasty
What is step 1 in the medical approach to asthma treatment (NICE guildelines)
Monitored initiation of ICS - to confirm an asthma diagnosis
What is step 2?
[Throughout ALL steps a SABA (salbutamol) should be given as a reliver]
If asthma confirmed keep on low dose ICS
