RESP - Asthma

Question 1

What is the pathophysiology of asthma?

• acute
• chronic
• airway remodelling

Answer 1

Acute:

• Mediator release from mast cells & eosinophils: histamine, prostaglandins, leukotrienes and cytokines in response to allergen (in many cases).
• Bronchoconstriction, oedema, mucous.

Chronic Inflammation:
- Early structural changes involving cell recruitment and epithelial damage.

Airway Remodelling:
- Smooth muscle & goblet cell hyperplasia, & thickening of basement membrane.

Question 2

(3) main aspects in asthma pathophysiology that leads to airflow limitation & airway hyperresponsiveness (AHR)

Answer 2

• Smooth Muscle Contraction
• Mucus hypersecretion
• Oedema

Question 3

Key symptoms of asthma

Answer 3

• SOB – often episodic, particularly nocturnal or early morning. Often with exercise.
• Wheezing
• Chest tightness
• 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

Question 4

(4) Predisposing factors for asthma

Answer 4

• Genetic predisposition: no single gene
• Atopy: what is this? Includes allergic rhinitis
• Airway hyperresponsiveness (AHR)
• Sex: severe persistent asthma more common in women

Question 5

Examples of triggers for asthma

Answer 5

• Allergens
• Pollutants, tobacco smoke, occupational fumes
• URTIs
• Exercise
• Changes in weather
• Emotion, anxiety
• Food, additives
• Medication (aspirin, beta blockers)
• GORD

Question 6

What signs might be present in a patient with asthma?

Answer 6

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

•Auscultatory findings:
–Prolonged expiratory phase with wheeze
–Reduced breath sounds,
–Reduced heart sounds.

Other findings:
–Pulsus paradoxus: >10mmHg drop in Systolic blood pressure with inspiration

Question 7

(3) How do you diagnose asthma?

Answer 7

need to demonstrate reversible airflow obstruction (in the appropriate clinical setting)

1. Peak Expiratory flow: 20% variation day to day (or morning to evening).

Or
2. Spirometry: 200ml & 12% improvement with bronchodilator

If unremarkable spirometry:
3. Bronchoprovocation Testing
- Measures the pathophysiological feature of BRONCHIAL HYPERRESPONSIVENESS.
•Types:
–Direct: methacholine, histamine,
–Indirect: hypertonic saline, eucapneic hyperventilation, mannitol

Question 8

Causes of wheezes

Answer 8

•Asthma
•Bronchitis
•Exacerbation of COPD
•Vocal Cord Dysfunction
•Obstructing endobronchial lesion
–May have focal wheeze
–Tumour, foreign body
•Heart failure

Question 9

Goals of asthma treatment

Answer 9

• Control symptoms
• Prevent exacerbations
• 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

Question 10

Treatment of asthma in adults

Answer 10

•Patient focused
–what are the patient’s goals?
–education
–action plan (see later)
–psychosocial factors
•Avoid triggers
•Treat conditions that could exacerbate asthma
•Medication

Question 11

Discuss medications for asthma

Answer 11

•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
•Oral corticosteroids
•Combination inhalers (ICS/LABA)
•Leukotriene receptor antagonists
•Anti-IgE

Question 12

Local SE of ICS in asthma

Answer 12

–hoarse voice, thrush
–need to rinse mouth
–not as bad with ciclesonide

Systemic SE are uncommon unless very high dose

Question 13

If not improving asthma in a young adult/adolescent, what would you do?

Answer 13

• 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

Question 14

What may be the reasons to poor adherence in asthma Mx?

Answer 14

–Symptom remission
–Multiple medications, fear of dependence and long term side effects
–Chronicity of asthma
–Cost
–Poor understanding (particularly preventer meds), poor supervision
–Cultural issues

Question 15

What is an “asthma action plan” and what might be the important features of such a plan?

Answer 15

• 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

Question 16

Mx of severe acute asthma episode

Answer 16

• Oxygen (essential)
• Oral prednisolone or IV hydorcortisone
• Regular bronchodilators
• Urgent ICU assessment for observation and possible intubation
• IV magnesium

Question 17

What are the Risk factors for increased risk of death from asthma?

Answer 17

• Previous life threatening attack of asthma
• Recent hospitalization for asthma
• Poor psychosocial supports
• Poor adherence to preventive treatments
• Difficulty accessing treatment