Flashcards in RESP - Asthma Deck (17)
What is the pathophysiology of asthma?
- airway remodelling
- Mediator release from mast cells & eosinophils: histamine, prostaglandins, leukotrienes and cytokines in response to allergen (in many cases).
- Bronchoconstriction, oedema, mucous.
- Early structural changes involving cell recruitment and epithelial damage.
- Smooth muscle & goblet cell hyperplasia, & thickening of basement membrane.
(3) main aspects in asthma pathophysiology that leads to airflow limitation & airway hyperresponsiveness (AHR)
- Smooth Muscle Contraction
- Mucus hypersecretion
Key symptoms of asthma
•SOB – often episodic, particularly nocturnal or early morning. Often with exercise.
•Cough – dry or with some sputum production
•Reversible - recurrent with good and bad days, responds to medication but may resolve spontaneously
•There may be certain triggers
(4) Predisposing factors for asthma
•Genetic predisposition: no single gene
•Atopy: what is this? Includes allergic rhinitis
•Airway hyperresponsiveness (AHR)
•Sex: severe persistent asthma more common in women
Examples of triggers for asthma
•Pollutants, tobacco smoke, occupational fumes
•Changes in weather
•Medication (aspirin, beta blockers)
What signs might be present in a patient with asthma?
Reversible: Normal if not active.
During an attack: Anxiety, tachypnoea, cyanosis
•Bronchospasm: leads to ↑ WOB and hyperinflation
–Pursed lip breathing
•Compensation through increased effort:
–Elevated respiratory rate,
–Accessory muscle activation,
–Substernal intercostal retraction
–Prolonged expiratory phase with wheeze
–Reduced breath sounds,
–Reduced heart sounds.
–Pulsus paradoxus: >10mmHg drop in Systolic blood pressure with inspiration
(3) How do you diagnose asthma?
need to demonstrate reversible airflow obstruction (in the appropriate clinical setting)
1. Peak Expiratory flow: 20% variation day to day (or morning to evening).
2. Spirometry: 200ml & 12% improvement with bronchodilator
If unremarkable spirometry:
3. Bronchoprovocation Testing
- Measures the pathophysiological feature of BRONCHIAL HYPERRESPONSIVENESS.
–Direct: methacholine, histamine,
–Indirect: hypertonic saline, eucapneic hyperventilation, mannitol
Causes of wheezes
•Exacerbation of COPD
•Vocal Cord Dysfunction
•Obstructing endobronchial lesion
–May have focal wheeze
–Tumour, foreign body
Goals of asthma treatment
•Maximize lung function and prevent future lung function decline
•Maintain normal levels of activity
•Lowest dose of medication to achieve suitable asthma control and minimize side effects
Treatment of asthma in adults
–what are the patient’s goals?
–action plan (see later)
•Treat conditions that could exacerbate asthma
Discuss medications for asthma
•Beta 2 Agonists (symptom relievers)
–long and short acting
–relax smooth muscle, improve airway patency
–do not change the underlying inflammation
•Inhaled corticosteroids (preventer)
–reduce airway inflammation and AHR
•Combination inhalers (ICS/LABA)
•Leukotriene receptor antagonists
Local SE of ICS in asthma
–hoarse voice, thrush
–need to rinse mouth
–not as bad with ciclesonide
Systemic SE are uncommon unless very high dose
If not improving asthma in a young adult/adolescent, what would you do?
- Ask pt what he sees are the issues and check what he would like to do
- Education to improve adherence, along with an asthma plan
- Improve medication delivery
- Treat his allergic rhinits
- Stop smoking
- Restart inhaled corticosteroid±LABA (he might have more severe asthma than first thought)
- Regular review
What may be the reasons to poor adherence in asthma Mx?
–Multiple medications, fear of dependence and long term side effects
–Chronicity of asthma
–Poor understanding (particularly preventer meds), poor supervision
What is an “asthma action plan” and what might be the important features of such a plan?
•Need to be culturally appropriate
•Clear & Concise
•Available ie stuck to fridge.
Instructs them on what to look out for and how to control their Mx based on their symptoms
Mx of severe acute asthma episode
•Oral prednisolone or IV hydorcortisone
•Urgent ICU assessment for observation and possible intubation