Physiology of Asthma and COPD

Question 1

Describe the histopathology of an asthmatic patient (7)

Answer 1

1. Mucus plug in lumen made of mucus, plasma proteins and eosinophils (neutrophils in severe asthma)
2. Epithelial fragility
3. Thickened Basement Membrane
4. Smooth Muscle Hypertrophy
5. Submucosal gland hypertrophy leading to increased goblet cells
6. Vasodilation due to cytokines and histamine
7. Cellular Infiltration (eosinophils and neutrophils)

Question 2

What are the three components of COPD?

Answer 2

1. Chronic bronchitis
2. Small Airways Disease (bronchiolitis)
3. Emphysema

Question 3

Define Chronic Bronchitis

Answer 3

Hypersecretion of mucus from goblet cells due to long term inflammation.

Question 4

Define Small Airways Disease (Bronchiolitis)

Answer 4

Inflammation of bronchioles characterised by fibrotic deposits into the small airways. This causes the airway to become stenosed. The alveoli keeping them open are destroyed and therefore there is a narrowing in the airway

Question 5

Define Emphysema

Answer 5

Characterised by parenchymal and alveolar destruction leading to increase in the size of air spaces distal to terminal bronchioles - hyperinflation

Question 6

Histopathology - Asthma or COPD?

a. Inflammation
b. Airway Smooth Muscle Hypertrophy
c. Basement Membrane Hypertrophy
d. Fibrosis
e. Alveolar Degradation

Answer 6

Question 8

Describe the response of asthmatics to:

a. Bronchodilators (salbutamol)
b. Gluco-corticosteroids (beclomethasone)

Answer 8

a. Good
b. Good: causes a significant % reduction in bronchial biopsy cell content

Question 9

Name three cells involved in the airway inflammation of a patient with asthma.

Answer 9

1. Mast Cells
2. Eosinophils
3. Th2 Cells

Question 10

Name three cells involved in the airway inflammation of a patient with COPD.

Answer 10

1. Macrophages
2. Neutrophils
3. Th1 Cells

Question 11

Name four mediators involved in the airway inflammation of a patient with asthma.

Answer 11

1. Histamine
2. Cytokines: IL-4, IL-5
3. Lipid mediators: leukotrienes, prostaglandins PGD2 (bronchoconstriction, mucus secretion, plasma exudation)
4. NO (vasodilation)

Question 12

Name mediators involved in the airway inflammation of a patient with COPD.

Answer 12

Inflammatory: IFN, TNFa, CXCL8, LTB4 (neutrophil chemoattractant)

Emphyema: Proteases, ROS

Question 13

Describe the response of COPD patients to:

a. Bronchodilators (salbutamol)
b. Steroids (beclomethasone)

Answer 13

a. Poor
b. Usually very poor

This is because there is no bronchoconstriction in COPD

Question 18

Describe what happens in an Induced Sputum

Answer 18

Inhalation of hypertonic saline which causes patient to cough sputum up. It allows for a snapshot of what is happening in the airways in terms of cells, mediators, pathogens etc.