Asthma And COPD Flashcards
What is asthma ?
An inflammatory disorder of the conducting airways. The airways become hyper - responsive and constrict easily in response to a wide range of exogenous and endogenous stimuli.
What are some types of asthma ?
Allergic asthma
Non-allergic asthma
Late onset asthma
Asthma with fixed airflow limitations
Asthma with obesity
What are some features of allergic asthma ?
Most easily recognised type
Majority begins at childhood
Associated with a family history of eczema, allergic rhinitis or food and drug allergy
Usually respond well to inhaled corticosteroids
What are some features of non-allergic rhinitis ?
Not associated with allergy
Sputum contains neutrophils, eosinophils and only a few inflammatory cells
Often respond less well to ICS
What are some features of late onset asthma ?
Onset is in adult life particularly in women
Tends to be non allergic
Higher dose of ICS often required
What are some features of asthma with fixed airflow limitations ?
Seen in patients with long standing asthma
Thought to be caused by airway remodelling
What are some features of asthma with obesity ?
Some obese asthmatic people suffer with prominent respiratory symptoms with little eosinophilic airway inflammation
What is the pathogenesis of atopic asthma ?
Airway inflammation caused by exposure to an environmental allergen. This occurs by IgE binding to bronchial mast cells resulting in degranulation and the release of pro-inflammatory mediators.
What are the 2 phases of inflammation ?
Acute phase
Delayed phase
What are the results of inflammation in asthma ?
Bronchial hyper-reactivity
Symptoms of cough, wheeze and chest tightness
Signs of variable polyphonic wheeze
What are some common environmental allergens in atopic asthma ?
Faeces of house dust mite
Cat salivary antigens
Pollen
Fungal spores
Grain antigens
Rat antigens
What occurs in the acute inflammatory response in asthma ?
It is characterised by bronchoconstriction and airway oedema. This begins within minutes of allergen exposure and resolves within hours. Cross linking of mast cell bound IgE allergen results in degranulation and the release of :
. Histamine
. Protease
. Tissue necrosis factor
. Platelet activating factor
What occurs in the delayed inflammatory response ?
The pro - inflammatory mediators such as interleukin-5 released by mast cells recruit, basophils and TH2-lymphocytes.
This results in :
. Ongoing inflammation
. Sensitisation of sensory nerve endings resulting in bronchial hyper-responsiveness
What are some risk factors for asthma ?
Host factors - genetics, obesity and sex
Infections
Having allergens
Diet
Stress
Exposure to tobacco smoke
What are some clinical factors of asthma ?
Wheezing
SOB
Chest tightness
Cough ( +/- sputum )
Worsening at night or in the early morning
Symptoms are triggered by a viral infection, exercise, allergen exposure or changes in the weather.
Follow a diurnal pattern
What are some features of a severe attack of asthma ?
Difficulty in speaking
Tachypnoeic and breathless
Tachycardia
Pulses paradoxus
Silent chest
Drowsiness
Cyanosis
What type of resp failure is a severe asthma attack ?
Type 2 resp failure