Acute asthma

Question 1

Define asthma.

Answer 1

An asthma exacerbation is an acute or subacute episode of progressive worsening of symptoms of asthma, including shortness of breath, wheezing, cough, and chest tightness. It is characterised by intermittent airway obstruction and hyper-reactivity.

Question 2

What cell types are involved in asthma?

Answer 2

Mast cells, eosinophils, T cells, macrophages, neutrophils (near-fatal asthma) and epithelial cells.

Question 3

Asthma deaths are among the highest in which ethnicity?

Answer 3

Black ethnicity.

Question 4

What is the pathophysiology of asthma?

Answer 4

1. Inflammation:
   · Occurs secondary to an interaction of inflammatory cells, mediators and airway cells.
   · An initial trigger leads to the release of inflammatory mediators, leading to activation of other inflammatory cells.
   · This is a Th2 lymphocytic response with the presence of CD4+ lymphocytes.
   · CD4+ lymphocytes secrete interleukins.
   · These cells change the airway epithelium, airway tone and cause hyper-secretion of mucus and increased smooth muscle responsiveness.
2. Hyper-responsiveness:
   · Products of the inflammatory response induce smooth muscle contraction and consequent hyper-responsiveness.

Question 5

What are the 2 types of hyper-responsiveness?

Answer 5

1. Baseline fixed - related to airway remodelling.

2. Episodic variable - action of inflammatory mediators.

Question 6

What environmental triggers can lead to asthma?

Answer 6

· Viral infections.
· Bacterial infections.
· Allergen exposure. 
· Occupational exposure.
· Food additives and chemicals.

Question 7

What are the risk factors for asthma?

Answer 7

· FHx - of atopic disease – asthma, eczema, allergic rhinitis.
· Allergens.
· Atopic hx.

Question 8

What are the signs and symptoms of asthma?

Answer 8

· Recent URTI.
· Dyspnoea.
· Cough. 
· Expiratory wheezes. 
· Nasal polyposis.

Question 9

What investigations would you request if you suspected a patient had asthma?

Answer 9

· FEV1/FVC ratio.
· FEV1. 
· PEFR.
· CXR.
· FBC.
· Immunoassay for allergen-specific IgE. 
· O2 sats.
· ABG.
· Short-acting bronchodilator trial.

Question 10

Differentials?

Answer 10

· CF. 
· Chronic rhinosinusitis. 
· Tracheomalacia. 
· Vascular ring. 
· Foreign body aspiration. 
· Vocal cord dysfunction.
· Alpha-1 antitrypsin deficiency. 
· COPD.
· Bronchiectasis.
· PE. 
· Congestive heart failure.

Question 11

What is the treatment option for mild intermittent and exercise induced asthma?

Answer 11

Short-acting beta agonist PRN - salbutamol.

Question 12

What is the treatment option for mild to moderate persistent asthma?

Answer 12

· Inhaled corticosteroid - fluticasone, budesonide, beclometasone.
· Short-acting beta agonist PRN.
· Leukotriene-receptor antagonist - montelukast, theophylline.

Question 13

What is the treatment option for severe persistent asthma?

Answer 13

· Oral corticosteroid - prednisolone. 
· Inhaled corticosteroid. 
· Long-acting beta agonist - salmeterol, tiotropium. 
· Immunomodulator.
· Short-acting beta agonist PRN. 
· Oxygen.

Question 14

What complications can arise?

Answer 14

· Moderate/severe exacerbation.
· Airway remodelling - pathological changes as a result of persistent inflammation.
· Secondary to inhaled corticosteroid use / drug complications:
- Oral candidiasis.
- Dysphonia.
- Oesophageal candidiasis.