Asthma

Question 1

Signs of asthma

Answer 1

Polyphonic wheeze
Hyperresonant on percussion
Barrel chest

Question 2

Pathophysiology of asthma

Answer 2

A chronic inflammatory disorder of the airways:

• Immediate phase: (type 1 hypersensitivity) allergen causes interaction of IgE with mast cells, histamine released, causes bronchoconstriction
• Late phase: (type IV hypersensitivity) inflammatory cells release cytokines leading to an immune response, causes bronchospasm, thickening of BM, odema and mucus production

Airway narrowing leads to reduced ventilation of alveoli, causes V/Q mismatch and reduced gas exchange

Question 3

Questions in asthma history

Answer 3

Family history
Allergies
Smoking 
Dry cough? Worse at night? 
Triggers?

Question 4

Investigations of asthma

Answer 4

Low PEFR
Low FEV1/FVC ratio - reversible with salbutamol
Skin prick tests for allergens

Question 5

Describe the steps in the management of asthma

Answer 5

1. Inhaled short acting B2-agonist when required eg. Salbutamol
2. Addition of inhaled steroid eg. Budesonide
3. Addition of long acting B2-agonist (LABA) eg. Formoterol, salmeterol
4. Increase inhaled steroids/ add 4th drug (methylxanthines eg. Theophylline, muscarinic antagonist eg. Ipatropium bromide)
5. Addition of an oral steroid/ anti-IgE therapy

Question 6

Describe the principles of treatment in asthma

Answer 6

Aims to minimise symptoms
Minimise need for reliever medication 
Reduced exacerbation frequency
Reduce limitation on physical activity
Give normal lung function

Question 7

Mechanism of action of B2-agonists

Answer 7

Bind to B2 receptors, increase cAMP levels, reduced Calcium, reduced activation of myosin light chain kinase, prevents muscle contraction.
Causes bronchodilation

Question 8

ADRs and contraindications of B2 agonists

Answer 8

ADRs: tachycardia, palpitations, tremors
Contraindications: cardiac ischaemia, arrhythmias

Question 9

Mechanism of action of corticosteroids in asthma

Answer 9

Anti inflammatory effect.

Suppress gene transcription in inflammatory cells and repress inflammatory responses -> apoptosis of inflammatory cells.

Question 10

ADRs of corticosteroids

Answer 10

Croaky voice, sore throat, thrush

Question 11

Give an example of a combined inhaler and what it contains

Answer 11

Symbicort

Mixture of budenoside and formoterol

Question 12

How would you treat acute severe asthma

Answer 12

Give oxygen
Nebulised salbutamol
Oral prednisolone
- if not responding ass nebulised ipratropium bromide

Question 13

Symptoms of asthma

Answer 13

Breathlessness
Chest tightness
Cough - dry, worse at night
Brought on by triggers

Question 14

Asthma differential diagnosis

Answer 14

Alpha-1-antitrypsin deficiency
COPD
Bronchiectasis
Upper resp tract infection
Foreign body in airway