Asthma (RESP) Flashcards
Define asthma.
Chronic inflammatory airway disease characterised by reversible, intermittent airway obstruction and hyper-reactivity
What is asthma characterised by? (3)
- bronchial hyper-responsiveness
- episodic acute asthma exacerbations
- reversible airflow obstruction
When do the symptoms of allergic asthma begin?
Childhood
What is allergic asthma associated with?
Atopy e.g.
- allergic rhinitis
- eczema
What gender is asthma more common in?
Males
Describe the pathophysiology of asthma.
- IgE-mediated type 1 hypersensitivity leading to mast cell degranulation and release of histamine
- 3 main pathological processes include:
- bronchial hyper-responsiveness
- bronchial inflammation
- endobronchial obstruction
What are the main pathological processes in asthma? (3)
- bronchial hyper-responsiveness
- bronchial inflammation
- endobronchial obstruction
What factors contribute to airway narrowing in asthma? (3)
- bronchial muscle contraction due to stimuli
- mucosal swelling/inflammation caused by mast cell and basophil degranulation leading to release of inflammatory mediators
- increased mucus production
What are some of the key features of asthma?
- recurrent episodes of SOB, chest tightness, wheezing or coughing
- characterised by an expiratory wheeze (but in severe asthma, poor air entry = chest is silent)
- may develop progressive, irreversible, obstructive lung disease
What are the clinical features of asthma? (9)
- episodic symptoms
- expiratory wheezes
- dyspnoea
- dry cough
- chest tightness
- diurnal variability of symptoms (worse at night/early morning)
- historical record of variable peak expiratory flow (PEF) or FEV1
- nasal polyposis
- recent upper respiratory tract infection
When is the dry cough in asthma worse? (3)
- at night
- with exercise
- with exposure to irritants
What are some precipitating factors/triggers for asthma?
- cold air
- viral infection
- drugs
- exercise
- emotions
- allergens - ask about dust mites, pollen, fur, pets
- smoking
- pollution
What is key in the Hx of asthma?
Symptoms come and go in response to triggers
What are some things to ask asthma patients?
- ask about previous hospitalisation due to acute asthma attacks - gives indication of severity of asthma
- ask about Hx of atopic disease:
- Semter’s Triad: asthma, nasal polyps, aspirin sensitivity
- nasal polyposis
- ask if symptoms remit at weekend - may be triggered at work (occupational asthma - main trigger isocyanate)
What are some findings on examination for asthma?
- prolonged expiratory wheeze
- tachypnoea
- use of accessory muscles
- polyphonic wheeze
- hyperinflated chest
- hyper-resonant percussion
- reduced air entry
- prolonged expiratory phase on auscultation
What are the risk factors for asthma?
- Fx
- allergens/irritants e.g. dust mites, pets
- atopic disease history (eczema, allergic rhinitis)
- cigarette smoking / vaping
- respiratory viral infection early in life
- nasal polyposis
- low socioeconomic status
When do we suspect a high probability of asthma? (5)
- recurrent episodes of symptoms (attacks)
- wheeze confirmed by a healthcare professional
- positive history of atopy
- historical record of variable airflow obstruction (spirometry)
- no features to suggest an alternative diagnosis
What do we do in patients with a high probability of asthma?
6 week trial of ICS - if there is a good response, then it can be diagnosed as asthma