Week 5 - Asthma

Question 1

Is obstruction constant or intermittent in asthma?

Answer 1

-Intermittent

Question 2

What are the two major players in asthma?

Answer 2

• Bronchial hyperresponsiveness and hypersensitivity

- Airway obstruction

Question 3

What causes airway obstruction in asthma?

Answer 3

• Airway oedema
• Mucus hypersecretion
• Smooth muscle hyperplasia

Question 4

What are the main cells involved in asthma?

Answer 4

-Eosinophils, mast cells and Th2 lymphocytes

Question 5

Describe the pathophysiology of asthma

Answer 5

• Airway inflammation and oedema caused by bronchial hyperresponsiveness -> mast cell, eosinophil and th2 lymphocyte response to exo/endogenous stimuli
• cytokine release and smooth muscle remodelling leads to thicker walls with narrower lumen
• IgE mediated Acute bronchoconstriction as a response to inflammation further narrows lumen
• Mucus hypersecretion
• All cause increased resistance to airflow

Question 6

Why does hyperinflation occur in asthma?

Answer 6

-Increased resistance to airflow cuses decreased expiratory flow rates and hyperinflation

Question 7

Name some major precipitating factors of asthma attacks

Answer 7

• Cold air
• Allergens (pollen/animals)
• Exercise
• Fumes -> car, smoke, perfume
• Drugs -> NSAIDs

Question 8

Describe the immediate response to stimuli in asthma

Answer 8

• 20 mins

- Interaction of allergen and IgE -> mast cell degranulation-> histamine, PGs and leukotrienes released -> inflammation

Question 9

Describe the late phase response to stimuli in asthma

Answer 9

• 3-12 hours

- All inflammatory cells eg eosinophils, lymphocytes, neutrophils release mediators and cytokines

Question 10

How is asthma diagnosed?

Answer 10

• Based on history of recurrent symptoms (wheeze, cough, SoB)
• Examination -> Hyperresonant and hyperinflation
• Investgations -> decreased PEFR, decreased FVC1:FVC ratio

Question 11

How is acute asthma treated?

Answer 11

-O SHIT
(Oxygen, Salbutamol (B2 agonist), Hydrocortisone (corticosteroid), Ipratropium(bronchodilator) and Theophyline (M3 antagonist))

Question 12

How is asthma treated?

Answer 12

• Lifestyle changes to minimise triggers
• Salbutamol
• corticosteroid

Question 13

What is a wheeze?

Answer 13

-high pitched noise on expiration due to narrowing of airways

Question 14

What are the signs and symptoms of asthma?

Answer 14

• Wheeze
• Dry Cough which is worse at night
• Exercise induced
• SoB

Question 15

Why is a cough worse at night in asthma?

Answer 15

-Increased parasympathetic innervation causes bronchoconstriction via M3

Question 16

Why is the cough dry in asthma?

Answer 16

-Mucus too low down to cough up

Question 17

Define asthma

Answer 17

-Chronic inflammatory disease of the airway causing spasm and swelling so that the airway narrows