Asthma

Question 1

What is the typical onset of asthma?

Answer 1

3-5 years

Question 2

What are some causes/triggers of asthma?

Answer 2

1) Environmental allergen eg. dust, pollen, fur
2) Viral infections eg. rhinovirus
3) Cold air
4) Emotion eg. stress or excitement
5) Irritant vapours and fumes eg. cigarette smoke, perfume
6) Genetic factors
7) Drugs eg. NSAIDs, beta-blockers
8) Atmospheric pollution eg. sulphur dioxide, ozone, particulates
9) Exercise
10) Occupational sensitisers eg. wood dust, latex, rat urine

Question 3

What are the features of extrinsic (atopic) asthma?

Answer 3

• Associated with atopy (esp. eczema, hayfever)
• Typical onset in childhood
• May also be associated with sensitisers/exposure

Question 4

What are the features of intrinsic (non-atopic) asthma?

Answer 4

• No personal or family history of asthma/atopy
• Typical onset in middle age
• Often onset following upper airway infection

Question 5

What are the triad of features in asthma?

Answer 5

1) Airway obstruction (reversible)
2) Airway hyper-responsiveness
3) Airway inflammation

Question 6

What are the changes seen in severe chronic asthma?

Answer 6

1) Dilated blood vessels
2) Thickened basement membrane
3) Mucus plug with eosinophils and desquamated epithelial cells
4) Mast cells
5) Oedema
6) Hypertrophied smooth muscle
7) Infiltration of inflammatory cells (mononuclear cells, eosinophils)

Question 7

What are the symptoms of asthma?

Answer 7

cough, wheeze, chest tightness, shortness of breath, often worse at night (diurnal variation)

Question 8

What are the signs of an exacerbation of asthma?

Answer 8

• Difficulty completing sentences
• Wheeze
• Tachypnoea (↑ respiratory rate)
• Tachycardia (↑ heart rate)
• Use of accessory muscles
• Reduced breath sounds – if severe

Question 9

How do you diagnose asthma?

Answer 9

No gold standard test

Trial of treatment and assess response

Reversibility on spirometry, before/after salbutamol

Diurnal variation on Peak Flow monitoring

(Fractional exhaled Nitric Oxide (FeNO))

Question 10

How can you manage asthma acutely?

Answer 10

• Oxygen
• Beta-2 agonist bronchodilators
• Corticosteroids (prednisolone or hydrocortisone)
• Ipratropium bromide
• Magnesium sulphate
• IV aminophylline
• Antibiotics