Asthma Flashcards
How many people are affected with asthma?
1 in 6 children
1 in 9 adults
How many children grow out of asthma?
1/3-1/2
What is the pathophysiology of asthma?
Acute - Mediator release from mast cells and eosinophils in response to allergen - Bronchoconstriction - Oedema - Mucus Chronic inflammation - Early structural changes involving - Cell recruitment - Epithelial damage Airway remodelling - Smooth muscle and goblet cell hyperplasia - Thickening of basement membrane
What mediators are released by mast cells and eosinophils?
Histamine
Prostaglandins
Leukotrienes
Cytokines
What are the symptoms of an acute asthma attack?
SOB Wheezing Chest tightness Cough Reversible May be certain triggers
What are the features of shortness of breath in asthma?
Episodic
Particularly nocturnal/early morning
Often with exercise
What are the predisposing factors for asthma?
Genetic predisposition
Atopy
Airway hyper-responsiveness
Sex - severe persistent asthma more common in women
What are some triggers for asthma?
Allergens Pollutants Tobacco smoke Occupational fumes URTIs Exercise Changes in weather Anxiety Food/additives Medication - Aspirin - Beta blockers GORD
What are the signs of asthma?
Normal exam if not active During attack - Anxiety - Tachypnoea - Cyanosis - Bronchospasm > increased work of breathing and hyperinflation - Pursed-lip breathing - Compensation through increased effort - Elevated RR - Accessory muscle activation - Substernal intercostal retraction - Pulsus paradoxus
Why do patients in an asthma attack do pursed-lipped breathing?
Auto end-expiratory pressure increase
What are the auscultatory findings of an asthma attack?
Prolonged expiratory phase with polyphonic wheeze
Reduced breath sounds
Reduced heart sounds
When does pulsus paradoxus occur?
In severe, life-threatening asthma
What investigations can be carried out to confirm the diagnosis of asthma?
Peak expiratory flow: 20% variation day to day
Spirometry: improvement with bronchodilator
Bronchoprovation testing, if spirometry unremarkable
Other than asthma, what can cause a wheeze?
Bronchitis Bronchiectasis Exacerbation of COPD Vocal cord dysfunction Obstructing endobronchial lesion - Monophonic Heart failure
What are the goals of asthma management?
Control symptoms
Prevent exacerbations
Maximise lung function and prevent future lung function decline
Maintain normal levels of activity
Lowest dose of medication to achieve suitable asthma control and minimise side effects
How are the goals of asthma management achieved?
Patient focused - What are the patient's goals? - Education - Action plan - Psychosocial factors Avoid triggers Treat conditions that could exacerbate asthma Medications
What is the mechanism of action of beta-2 agonists?
Relax smooth muscle
Improve airway patency
Symptom relievers > don’t change underlying inflammation
What is the mechanism of action of inhaled corticosteroids?
Reduce airway
- Inflammation
- Hyper-responsiveness
What medications can be used the in the management of asthma?
Beta-2 agonists - Short-acting - Long-acting Inhaled corticosteroids Oral corticosteroids Combination inhalers Leukotriene receptor antagonists Long-acting anticholinergic Anti-IgE
What are the adverse effects of inhaled corticosteroids?
Local - Hoarse voice - Thrush > need to rinse mouth Systemic - Not common unless in very high dose
Why might adherence in asthma management be poor?
Symptom remission Multiple medications Fear of dependence Long-term side effects Chronicity of asthma Cost Poor understanding Cultural issues
What is the acute management of an asthma attack?
Oxygen Oral prednisolone/IV hydrocortisone Regular bronchodilators Urgent ICU assessment for - Observation - Possible intubation IV magnesium
What is the mechanism of action of magnesium in acute asthma management?
Inhibits ACh > inhibits smooth muscle contraction
What are the risk factors for increased risk of death from asthma?
Previous life-threatening attack Recent hospitalisation for asthma Poor psychosocial supports Poor adherence to preventive treatments Difficulty accessing treatment
