*Obstructive Airway Disease

Question 1

What is obstructive airway disease?

Answer 1

Any respiratory disease characterised by air trapping caused by either decrease airway diameter or increased airway secretions, or both

Question 2

what are 3 obstructive airway disease?

Answer 2

Asthma
Chronic bronchitis
Emphysema

Question 3

What is asthma/ COPD overlap syndrome?

Answer 3

Not clearly defined but patients with features of asthma and COPD (e.g. atopic smoker with partially reversible airway obstruction) - COPD with reversibility and eosinophilia who are steroid responsivE

Question 4

What causes the turbulent airflow in asthma and COPD?

Answer 4

Mucosa and sub-mucosa become inflamed and invaginate and therefore obstruct airflow

Question 5

what type of leukocytes are involved in COPD and asthma?

Answer 5

COPD = neutrophil
Asthma = eosinophil

Question 6

How can the tone of the smooth muscle be described in COPD and asthma?

Answer 6

COPD = hypertrophic
Asthma = twitchy

Question 7

What 3 sets of words can be used to describe asthma?

Answer 7

Early onset/ late onset
Atopic (allergic)/ non-atopic
Extrinsic (external factor)/ intrinsic (internal factor)

Question 8

What is the asthma triad?

Answer 8

Airway inflammation
Reversible airflow obstruction
Airway hyperresponsivenes (hyperreactivity)

Question 9

What is the evolution of asthma?

Answer 9

Bronchoconstriction (brief symtpoms)
Chronic airway inflammation (exacerbations airway hyperresponsiveness)
Airway remodelling (fixed airway obstruction = COPD like symptoms)

Question 10

What are the hallmarks of asthma remodelling? (3)

Answer 10

Basement membrane = thickened
Submucosa = collagen deposition
Smooth muscle = hypertrophy

Question 11

What is the inflammatory cascade in asthma? + treatment?

Answer 11

Genetic predisposition + triggers (viruses, allergen, chemical, nutrition) - avoidance
Eosinophilic inflammation - anti-inflamatory (corticosteroid)
TH2 cells release mediators (Interleukins e.g. IL-12, IL-4, IL-5) - anti-leukotriene/ histamine, anti-IgE, anti-IL5)
Twitchy smooth muscle (hyper-reactivity) - bronchodilators (beta-2 agonists, muscarinic antagonists)

Question 12

What are examples of the environmental factors that can affect asthma?
Genetic factors?

Answer 12

Age, gender, obesity, infeciton, atopic status, allergin exposure
Genetic = Epithelial-specific asthma gene signature

Question 13

Examples of some asthma triggers?

Answer 13

Animal dander
Dust mites
Pollens
Fungi
Exercise 
Viral infection
Smoke
Cold
Chemicals
drugs (NSAIDs, beta-blockers)

Question 14

What are the clinical signs of asthma?

Answer 14

Episodic symptoms and signs
diurnal variability (nocturnal/ early morning)
non-productive cough, wheeze
triggers
assocaited atopy
family history

Question 15

What can be used to help diagnose asthma?

Answer 15

History and examination
diurnal variation of peak flow rate
Reduced forced expiator rate (FEV1/FVC 15%)
Provocation testing leads to bronchospasm

Question 16

What can be used to provoke asthma in the clinical setting?

Answer 16

Exercise

Histamine/ metacholine/ mannitol

Question 17

What are the 3 components of COPD caused by noxious particles or gases?

Answer 17

Mucociliary dysfunction
Neutrophilic inflammation
Tissue damage
(these lead to the development of obstruction and ongoing disease progression)

Question 18

What are the characteristics of COPD? (2)

Answer 18

Exacerbations

Reduced lung fucntion

Question 19

What is the disease process in COPD?

Answer 19

Inhaled noxious chemicals causes inflammation of the lungs (if normal protective mechanisms aren’t working properly)
Cigarette smoke activated macrophages and airway epithelial cells which release neutrophili chemotaxis factor
Neutrophils and macrophages then releases proteases that break down lung parenchyma (emphysema)and stimulate mucous hyper secretion (chronic bronchitis)
Cytotoxic T cells may also be involved

Question 20

In COPD, what is there an imbalance of?

Answer 20

Proteases and anti-proteases (e.g. alpha1-antitrypsin)

Question 21

What are the features of chronic bronchitis?

Answer 21

Chronic neutrophilic inflamation
mucus hypersecretion
mucociliary dysfunction
altered lung biome
smooth muscle spasm and hypertrophy
Partially reversible

Question 22

What are the features of emphysema?

Answer 22

Alveolar destruction
Impaired gas exchange
Loss of bronchial support
Irreversible

Question 23

What are indicative of high risk COPD?

Answer 23

2 exacerbations or more within the past year or FEV2 less than 50%

Question 24

Clinical features of COPD?

Answer 24

Chronic symptoms (not episodic)
Smoking
Non-atopic
Daily productive cough
Progressive breathlessness
Frequent infective exacerbations
Chronic bronchitis = wheezing
Emphysema = reduced breath sounds

Question 25

What is the chronic cascade in COPD?

Answer 25

Progressive fixed airflow obstruction
Imparied alveolar gas exchange
Respiratory failure (decrease PaO2, increased PaCO2)
Pulmonary hypertension
Right ventricular hypertrophy/ failure (for pulmonale)
Death
(stopping smoking arrests further decline in lung volume)

Question 26

Corticosteroid and bronchodilator response in asthma v COPD

Answer 26

Good response in asthma

Poor response in COPD