Asthma

Question 1

Narrowing of the airways in asthma is caused by… (2)

Answer 1

Bronchoconstriction

Airway inflammation

Question 2

3 fundamental aspects of asthma

Answer 2

Airflow obstruction
Bronchial hyper responsiveness
Airway inflammation

Question 3

What is the most common precipitant of asthma exacerbations in children under 5?

Answer 3

Respiratory viral infections

Question 4

Early phase of asthma

Answer 4

Starts after specific or non specific stimulation of airway mast cells
Release of preformed and stored mediators leading to bronchospasm, mucosal edema, vasodilatation, and initiation of late phase reaction
Easily reversed or prevented by beta 2 agonists (can also use mast cell stabilizers to prevent)

Question 5

What are some preformed mediators that contribute to asthma?

Answer 5

Histamine
Prostaglandins
Leukotrienes
Platelet aggregating facotr

Question 6

Late phase reaction of asthma

Answer 6

Recruitment and activation of immune cells
Release of pro inflammatory cytokines and mediators that lead to a slower but more sustained airway narrowing
Treated and prevented by corticosteroids (can also use mast cell stabilizers to prevent)

Question 7

Cholinergic innervation in asthma

Answer 7

ACh can bind to M3 receptors on smooth muscle cells and cause bronchoconstriction

Question 8

Sympathetic innervation in asthma

Answer 8

Some adrenergic receptors are present on SMCs causing bronchodilation

Question 9

Mast cells or eosinophils release chemokines that cause..

Answer 9

Inflammation and bronchoconstriction

Question 10

Sympathomimetic agents

Answer 10

Beta agonists
Epinephrine, ephedrine, isoproterenol
Increase production of cAMP causing bronchodilation
Acts quickly, but not for long

Question 11

Beta 2 adrenergic receptor selective agents

Answer 11

Salbutamol
Administered via inhalers
Bronchodilation achieved in 30 mins and effects last for 3-4 hours

Question 12

Methylxanthine drugs

Answer 12

2 actions:
1. Inhibits actions of PDE to increase stability of cAMP
2. Inhibits actions of adenosine by blocking adenosine receptors (block bronchoconstriction)
Ex: caffeine, theophylline, theobromine

Question 13

Antimuscarinic drugs

Answer 13

Block the effects of ACh at muscarinic receptors –> bronchodilation
Ex: atropine and ipratropium bromide
Slightly less effective compared to beta agonists

Question 14

Corticosteroids

Answer 14

Block production of cytokines by mast cells and eosinophils
Inhibit inflammation of asthmatic airways
Ex: prednisone
Aerosol treatment is best
Can be used for prolonged periods safely

Question 15

Effects of leukotrienes (4)

Answer 15

Bronchoconstriction
Mucosal edema
Hyper reactivity of bronchi
Mucus hypersecretion

Question 16

5-lipoxygenase inhibitors

Answer 16

Ex: Zileuton

Inhibit the synthesis of leukotrienes by inhibiting the 5-lipoxygenase

Question 17

Leukotriene receptor blockers

Answer 17

Ex: Montelukast
Inhibit the binding of leukotrienes to receptors in the target tissue
Administered orally
Very effective in reducing the frequency of bronchial exacerbations
Good for treating aspirin induced asthma

Question 18

Anti-IgE monoclonal antibodies

Answer 18

Omalizumab

Block the actions of IgE in asthma

Question 19

Calcium channel blockers

Answer 19

Nifedipine and verapamil
Induce smooth muscle cell relaxation
Not as effective as salbutamol

Question 20

Nitric oxide donors

Answer 20

Induce smooth muscle cell relaxation

Question 21

How to treat severe attacks

Answer 21

Require treatment with oxygen, frequent administration of aerosolized salbutamol and systemic prednisone