Asthma- general

Question 1

What characteristic features are at the three corners of the “asthma triad”?

Answer 1

Reversible airflow obstruction
Airway inflammation
Airway hyperresponsiveness

Question 2

a) Why can there be airway remodelling in asthma?

b) What are hallmarks of this remodelling?

Answer 2

a) Changes in the airways due to chronic inflammation.
b) Thickening of the basement membrane
Collagen deposition in the submucosa
Smooth muscle hypertrophy

Question 3

Describe the clinical syndrome of asthma

Answer 3

Episodic symptoms and signs
Diurnal variability- nocturnal/early morning
Non-productive cough/wheeze
Triggers
Associated atopy (rhinitis, conjunctivitis, eczema)
Family history of asthma
Wheezing due to obstructed airways

Question 4

How is a diagnosis of asthma made?

Answer 4

Based on:
History and examination
Diurnal variation of peak flow rate
Reduced forced expiratory ratio (FEV1/FVC = <15%)
Provocation testing results in bronchospasm (exercise, inhalation of histamine/allergen)

Question 5

What is the difference between extrinsic and intrinsic asthma?

Answer 5

Extrinsic asthma is caused by response to an inhaled antigen.
Intrinsic asthma is caused by non-immune mechanisms (e.g. cold, exercise, aspirin).

Question 6

What type of hypersensitivity is involved in asthma?

Answer 6

Type 1 hypersensitivity

Question 7

Describe the pathology of asthma

Answer 7

Narrowed, oedematous airways
Mucous plugs
Inflammatory cells (eosinophils, lymphocytes, plasma cells)
Epithelial cell damage