Dynamic Lung Mechanics

Question 1

What is the regulation of the pulmonary vasculature and glands by the autonomic nervous system?

Answer 1

Parasympathetic
- muscarinic
- contracts smooth muscle
- causes mucus gland secretion
Sympathetic
- alpha - constricts blood vessels
- beta 2 - relaxes respiratory smooth muscle

Question 2

What is asthma?

Answer 2

A chronic inflammatory condition in which there is recurrent reversible airway obstruction in response to irritant stimuli

Question 3

What types of asthma are there?

Answer 3

Extrinsic
- associated with specific allergic reactions
Intrinsic
- not associated with any known allergen

Question 4

Give some examples of asthma triggers

Answer 4

Upper respiratory infections
Weather changes
Allergens
Exercise
Emotions
Certain medications

Question 5

What happens when asthma is triggered?

Answer 5

Antigen binds to mast cell
Release of histamine, prostaglandins, interleukins
- mucous production
- bronchoconstriction
Also caused by vagal activation
- increased vascular permeability - oedema

Question 6

What are the delayed responses to an asthma trigger?

Answer 6

Increased vascular permeability
Immune cell infiltration
- eosinophils
- monocytes
-basophils
- T lymphocytes
Cytokine release
- IL 4,5,13
Inflammation
- oedema
- impaired mucociliary clearance
- reduced air flow
- airway hyperactivity
- airway injury

Question 7

What do bronchodilators do?

Answer 7

Reverse bronchoconstriction
Reduce airway resistance
Treat wheeze

Question 8

What do anti-inflammatory drugs do?

Answer 8

Relieve bronchial inflammation
Prevent further inflammation

Question 9

Give examples of bronchodilators

Answer 9

Beta 2 adrenoreceptor agonists
Xanthines
Muscarinic antagonists
Leukotriene synthesis inhibitors and antagonists

Question 10

What are short acting bronchodilators?

Answer 10

They last 3-5hrs
Salbutamol
Terbutaline

Question 11

What are long acting bronchodilators?

Answer 11

They last 8-12hrs
Salmeterol
Formoterol

Question 12

How do muscarinic receptor antagonists work?

Answer 12

Bronchodilation
Inhibits excess mucus secretion
Increases mucocilary clearance of bronchial secretions
No effect on late inflammatory stage

Question 13

What are short lasting muscarinic receptor antagonists?

Answer 13

Last <5hrs
Ipratropium bromide

Question 14

What are long acting muscarinic receptor antagonists?

Answer 14

Last <15hrs
Tiotropium bromide

Question 15

How do cysteinyl leukotriene synthesis inhibitors and receptor anatagonists work?

Answer 15

Prevent aspirin sensitive and exercise induced asthma
Decreases immediate and delayed responses
Action is additive with beta 2 adrenoreceptor agonists

Question 16

What are the two forms of any-inflammatory drugs?

Answer 16

Steroids
- glucocorticoids
Non-steroids
- Xanthines
- disodium cromoglycate

Question 17

How do steroids work?

Answer 17

Inhaled corticosteroids
Decreases cytokines
Decreases enzyme activity
Decrease peptides
Decreases adhesion
Decrease inflammation

Question 18

What is the pathophysiology of COPD

Answer 18

Tobacco smoke / air pollution
Continual bronchial irritation and inflammation
- chronic bronchitis
Breakdown of elastin in connective tissues
- emphysema
- airway instability
Airway obstruction
Air trapping dyspnoea
Frequent infections
- abnormal ventilation perfusion ratio
- hypoxemia
- hypoventilation

Question 19

How do you treat COPD?

Answer 19

Mild - short acting bronchodilators when needed
Moderate - regular treatment with one or more bronchodilators
- inhaled corticosteroids
Severe - regular treatment with one or more bronchodilators
- inhaled corticosteroids
- antibiotics
- long term O2 therapy