Obstructive Airways Disease

Question 1

Obstructive vs restrictive disease

Answer 1

Obstructive = airways, restrictive = lungs

Question 2

Examples of obstructive airway diseases

Answer 2

Asthma, emphysema and chronic bronchitis (COPD), asthma/COPD overlap syndrome

Question 3

The asthma triad

Answer 3

Reversible airflow obstruction, airway inflammation, airway hyperresponsiveness

Question 4

Dynamic evolution of asthma

Answer 4

Broncho-constriction (brief symptoms) → chronic airway inflammation (exacerbations, airway hyper responsiveness) → airway remodelling (fixed airway obstruction)

Question 5

Hallmarks of remodelling in asthma in the basement membrane, submucosa and mucosa

Answer 5

Basement membrane - thickening
Submucosa - collagen deposits
Mucosa - hypertrophy

Question 6

Inflammatory cascade in asthma

Answer 6

Inherited or acquired factors → eosinophilic inflammation → Mediators, TH2 cytokines → twitchy smooth muscle (hyperresponsiveness)

Question 7

What can be used to treat each of the following steps in the inflammatory cascade in asthma?:

1. Inherited or acquired factors
2. Eosinophilic inflammation
3. Mediators, TH2 cytokines
4. Twitchy smooth muscle

Answer 7

1. Avoidance of precipitant
2. Anti-inflammatory medication (corticosteroids, cromones, theophylline)
3. Leukotriene receptor agonists or antihistamines, monoclonal antibodies (anti-IgE, anti-IL5)
4. Bronchodilators (beta-2 agonists, muscarinic antagonists)

Question 8

Potential triggers of asthma

Answer 8

Allergens (animal dander, dust mites, pollen, fungi), exercise, viral infection, smoke, cold, chemicals, drugs (NSAIDs, Beta-blockers)

Question 9

When is asthma generally worse?

Answer 9

At night and in the morning. Diurinal variability

Question 10

Which antibody is increased in atopic asthma?

Answer 10

IgE

Question 11

Which blood cell is associated with asthma?

Answer 11

Eosinophil

Question 12

General steps in diagnosis of asthma

Answer 12

• History and examination
• Diurnal variability of peak flow
• Reduced forced expiratory ratio - FEV/FEV1 ratio <75%
• Reversibility to inhaled salbutamol (>15%)
• Provocation testing - bronchospasm (through exercise, histamine/methacholine//mannitol)

Question 13

Diurnal variations in peak flow rate in asthma

Answer 13

Generally peak flow is in the evening compared to the morning

Question 14

Components associated with development of obstruction and ongoing disease progression in COPD

Answer 14

Mucociliary dysfunction, inflammation, tissue damage

Question 15

Disease progression in COPD

Answer 15

Exposure to inhaled noxious particles and gases cause inflammation of the lungs that can lead to COPD if the normal protective and/or repair mechanisms are overwhelmed of defective
These aggravate the mucosal lining of airways and macrophages which release neutrophilic chemotactic factors
Macrophages and neutrophils release proteases which break down connective tissue and cause mucus hyper secretion and goblet cell hyperplasia
Cytotoxic T cells may also be involved in the inflammatory cascade

Question 16

2 diseases that fall under the term COPD

Answer 16

Chronic bronchitis and emphysema

Question 17

Chronic bronchitis:

• Characteristics
• Reversible or irreversible?

Answer 17

• Chronic neutrophilic inflammation, mucus hyper secretion, mucociliary dysfunction, altered lung microbiome, smooth muscle spasm and hypertrophy
• Partially reversible

Question 18

Emphysema:

• Characteristics
• Reversible or irreversible?

Answer 18

• Alveolar destruction, impaired gas exchange, loss of bronchial support
• Irreversible

Question 19

ABCD assessment tool in COPD

Answer 19

Spirometrically confirmed diagnosis → assessment of airflow limitation (FEV1) → assessment of symptoms/risk of exacerbations (via exacerbation history)

Question 20

Airflow limitation in COPD:

• GOLD 1
• GOLD 2
• GOLD 3
• GOLD 4

Answer 20

GOLD 1 - FEV1 ≥80% predicted
GOLD 2 - FEV1 50-79% predicted
GOLD 3 - FEV1 30-49% predicted
GOLD 4 - FEV1 <30% predicted

Question 21

Chronic cascade in COPD

Answer 21

• Progressive fixed airflow obstruction
• Impaired alveolar gas exchange
• Respiratory failure ↓PaO2, ↑PaCO2
• Pulmonary hypertension
• Right ventricular hypertrophy/failure (Cor pulmonare)
• Death

Question 22

How to prevent further decline in lung volume in COPD

Answer 22

Stopping smoking

Question 23

What is asthma/COPD overlap syndrome

Answer 23

COPD with blood eosinophilia >4%

Question 24

Difference between COPD and asthma/COPD overlap syndrome

Answer 24

• Blood eosinophilia >4%
• Responds better to inhaled corticosteroids with respect to exacerbation reductions
• More reversible to salbutamol

Question 25

Asthma treatment guidelines

Answer 25

``` Step 1 (intermittent) - short acting beta-2-agonists Step 2 (mild persistent) - add inhaled corticosteroids Step 3 (moderate persistent) - add LABA/LAMA, add LTRA/Theo/cromone Step 4 (Severe persistent) - add oral steroid, add anti-IgE, anti-IL5, anti-IL4-alpha ```

Question 26

Why may corticosteroids cause pneumonia in COPD?

Answer 26

Due to local immune suppression and impaired mucociliary clearance - especially with fluticasone

Question 27

When in COPD is prednisolone used?

Answer 27

Only for acute exacerbations

Question 28

Actions of a spacer device

Answer 28

- Avoids coordination problems with pMDI - Reduces oropharyngeal and pharyngeal side effects - Reduces systemic absorption from a swallowed fraction - Acts as a holding chamber for aerosol - Reduces particle size and velocity - Improves lung deposition

Question 29

Anti-IgE: - In which obstructive condition is it used in? - How is it administered? - Which patients may receive this?

Answer 29

- Asthma - Injection every 2-4 weeks - For patients with severe persistent allergic asthma despite max therapy

Question 30

Anti-IL5: - Which obstructive condition is it used in? - How is it administered? - Which patients may receive this?

Answer 30

- Asthma - Injection every 4/8 weeks - For patients with severe refractory eosinophilic asthma despite max therapy

Question 31

Anti-IL4 alpha: - Which obstructive condition is it used in? - How is it administered? - Which patients may receive this?

Answer 31

- Asthma - Injection every 2 weeks - For patients with severe refractory asthma despite max therapy