Asthma

Question 1

What is asthma?

Answer 1

Asthma is an obstructive disease meaning that it affects the airways.

Question 2

What are the different types of asthma?

Answer 2

Type 2 high/low - relates to TH2 inflammation
Early/late onset
Atopic/non-atopic
Extrinsic/intrinsic

Question 3

What are some of the characteristics of asthma?

Answer 3

Reversible airflow obstruction
Airway hyperresponsiveness
Type 2 airway inflammation - eosinophil is the usual effector cell.

Question 4

What is the dynamic evolution of asthma?

Answer 4

1. Bronchoconstriction causing brief symptoms
2. Chronic airway inflammation causing exacerbations of airway hyperresponsiveness.
3. Airway remodelling causing fixed airway obstruction when collagen is laid down

Question 5

What are some of the hallmarks of remodelling in asthma?

Answer 5

1. Thickening of the basement membrane.
2. Collagen deposition in the submucosa
3. Hypertrophy of smooth muscle

Question 6

What is type 2 inflammation in asthma?

Answer 6

This is the presence of one or more of - 
Presence of cytokines IL4/5/13
Raised total or specific IgE
Blood or sputum eosinophilia
Raised FeNO

Question 7

What is FeNO?

Answer 7

Fractional exhaled nitric oxide

Question 8

What are some of the triggers that can cause asthma symptoms to occur or worsen?

Answer 8

Allergens
Exercise
Viral infection
Smoke
Cold
Chemicals
Drugs - NSAIDS, Beta blockers

Question 9

What are the clinical features and symptoms of asthma?

Answer 9

Episodic diurnal variation
Non- productive cough
Triggers - in extrinsic asthma
Associated T2 comorbidities
Responsiveness to steroids or beta- agonists
Family history of asthma
Wheezing due to turbulent airflow.

Question 10

How is asthma diagnosed?

Answer 10

By history and examination.
Diurnal varitation peak flow rate.
Reduces forced expiratory ratio.
Reversibility to inhaled salbutamol >15%
Provocation testing

Question 11

What is the forced expiratory ration that is an indication of asthma?

Answer 11

FEV1/FVC < 75%

Question 12

What is provocation testing?

Answer 12

This is done to identify bronchospasm.

This can be done by exercise or chemical stimulants e.g. histamine, methacholine, mannitol

Question 13

What is the role of leukotrienes in asthma?

Answer 13

1. Contraction and proliferation of airway smooth muscle cells.
2. Influx of eosinophils to the area.
3. Decreased mucous transport.
4. Increased mucous secretion
5. Oedema

Question 14

What are some type 2 comorbidities in asthma?

Answer 14

Chronic rhinosinusitis with nasal polyps.
Atopic dermatitis
Allergic rhinitis
Eosinophilic oesophagitis

Question 15

What are some of the signs of T2 asthma?

Answer 15

Sensitive airway smooth muscle
Airway hyperresponsiveness
Mucous production
Exacerbations of symptoms

Question 16

What are some of the biomarkers of type 2 inflammation with asthma?

Answer 16

High IgE

High FENO - fractional exhaled nitric oxide

Question 17

What are the common types of T2 asthma?

Answer 17

Allergic asthma
Exercise induced asthma
Late-onset eosinophilic asthma