Asthma

Question 1

Asthma definition

Answer 1

obstructive lung disease characterised by paroxysmal and reversible airway bronchoconstriction, as a result of inflammation of the respiratory airways and bronchial hyperresponsiveness.

Question 2

Typical asthma feature re history

Answer 2

family history of atopy, which is the genetic tendency to develop allergic diseases. The atopic triad includes asthma, allergic rhinitis and atopic eczema.

Question 3

IL involved in asthma (sensitisation of mast cells)

Answer 3

IL-4: Facilitates class switching to IgE
IL-5: Facilitates release of eosinophils
IL-13: Stimulates mucus production

Question 4

What lung features result from remodelling after inflammation

Answer 4

• bronchial smooth muscle hypertrophy
• bronchoconstriction
• mucous gland hypertrophy
• vasodilation and increased vascular permeability.

Question 5

Key questions in asthma history

Answer 5

1. Diurnal variation (symptoms often worse in the morning)
2. Worsen following exercise or NSAIDs/beta-blockers

Question 6

Asthma investigations

Answer 6

Spirometry: FEV1/FVC <0.7 (obstructive spirometry) (bronchodilator reversibility)
Fractional exhaled nitric oxide (FeNO): >40 ppb in adults or >35 ppb in children
Peak flow variability >20%

Question 7

Acute asthma investigations

Answer 7

ABG: T2RF is a sign of a life-threatening attack.
Routine blood tests (including FBC, CRP): to look for precipitating causes of an asthma attack, eg infection
Chest x-ray: to exclude differentials and possibly identify a precipitating infection.

Question 8

Management of acute asthma attack

Answer 8

A
Ensure a patent airway
B
O2 - Sats 94-98%

Nebulisers: Salbutamol, Ipratropium

Steroids: oral Prednisolone or IV Hydrocortisone (if severe)

IV Magnesium Sulphate: if severe

IV aminophylline: if severe and
inadequate bronchodilatory response from nebulisers

If the patient does not improve following these measures, ICU input for invasive ventilation

Question 9

Non-pharma management of chronic asthma

Answer 9

Smoking cessation
Avoidance of precipitating factors (eg. known allergens)
Review inhaler technique

Question 10

Management of chronic asthma (as per BTS)

Answer 10

Step 1: short-acting inhaled B2-agonist (eg. Salbutamol)

Step 2: add low-dose inhaled corticosteroid steroid (ICS)
Step 3: add long-acting B2-agonist (eg. Salmeterol). If no benefit, stop this and increase ICS dose; if benefit but inadequate control, continue and increase ICS dose.
Step 4: Trial oral leukotriene receptor antagonist, high-dose steroid, oral B2-agonist

Please note that the NICE guidance on Asthma differs at Step 3.

Question 11

Asthma mimics

Answer 11

• Reflux
• Churg-Strauss
• Allergic Bronchopulmonary Aspergillosis (ABPA)