Obstructive Airway Disease

Question 1

What area is affected by obstructive disease?

Answer 1

Airways

Question 2

How many times does the airways bifurcate after the trachea bifurcation?

Answer 2

23

Question 3

What is the conducting zone?

Answer 3

Conducting zone of the respiratory system is made up of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles

Question 4

What is the function of the conducting zone?

Answer 4

Filter, warm, and moisten air and conduct it into the lungs

Question 5

What makes up the respiratory zone?

Answer 5

Respiratory bronchioles and the alveolar ducts

Question 6

What is the function of the respiratory zone?

Answer 6

Exchanging of gases

Question 7

Respiratory tract =

Answer 7

Conducting zone + Respiratory zone

Question 8

What is happening in obstructive lung disease?

Answer 8

People find it hard to exhale of the air in their lungs due to obstruction

Question 9

What is the main symptom that obstructive and restrictive lung disease share?

Answer 9

Shortness of breath with exertion

Question 10

Obstructive airway syndrome (3 components):

Answer 10

1) Chronic bronchitis 2) Emphysema 3) Asthma (umbrella term including COPD and asthma)

Question 11

3 main events in airway obstruction:

Answer 11

1) Mucosal invagination due to inflammation and oedema, which narrows the lumen 2) Increased tonicity in away smooth muscle 3) Alveolar wall breakdown

Question 12

What is the main cell causing inflammation in COPD?

Answer 12

Neutrophil

Question 13

What is the main cell causing inflammation in asthma?

Answer 13

Eosinophil

Question 14

What is COPD?

Answer 14

Progressive disease state characterised by airflow limitation that is not fully reversible, characterised by chronic bronchitis and emphysema

Question 15

What conditions does COPD encompass?

Answer 15

Chronic bronchitis and emphysema (and airway narrowing)

Question 16

What is chronic bronchitis?

Answer 16

Mucous hyper secretion due to mucous gland hypertrophy and increased number of goblet cells resulting from inflammation of bronchi and bronchioles

Question 17

What is emphysema?

Answer 17

Distention and damage of the alveoli with destruction of their walls leading to reduced gas exchange - becomes one large pouch’

Question 18

What is asthma?

Answer 18

Disease characterised by airway inflammation with increased airway responsiveness resulting in airway obstruction

Question 19

What is the asthma triad (characteristics of asthma)?

Answer 19

1) Airway inflammation (due to eosinophils) 2) Reversible airflow obstruction 3) Airway hyper responsiveness (smooth muscle becomes twitchy)

Question 20

Difference between asthma and COPD in general?

Answer 20

Asthma is caused primarily by airway inflammation and hyperreactivity leading bronchial muscle contraction that is reversible, while COPD is structural and histological changes (i.e. narrowing and remodelling) that is only partially reversible.

Question 21

What is atopic vs non-atopic asthma?

Answer 21

Atopic (60%) asthma indicates there is an allergic (IgG) reaction involved, non-atopic does not

Question 22

What is extrinsic vs intrinsic asthma?

Answer 22

Extrinsic means there is an identifiable external trigger involved, while if there is no identifiable factors then it is intrinsic

Question 23

What is the dynamic evolution of asthma over time?

Answer 23

1) Bronchoconstriction (causing brief symptoms) 2) Chronic airway inflammation 3) Airway remodelling (scarring due to persistent inflammation leading to fixed airway obstruction)

Question 24

What are the aims of treatment of asthma, considering the dynamic evolution?

Answer 24

Clear brief symptoms, Reverse exacerbations AHR and prevent fixed airway obstruction

Question 25

What are the hallmarks of remodelling in asthma?

Answer 25

- Basement thickening - Collagen deposition in the submucosa - Hypertrophy of the smooth muscle

Question 26

What is the inflammatory cascade in asthma?

Answer 26

1) Genetic loading for the cascade (initiates cascade when interact with triggers) 2) Eosinophilic inflammation occurs 3) Release of preformed allergic mediators e.g. histamine, leukotriene D4 and TH2 cytokines 4) Twitchy smooth muscle occurs (hyper-reactivity)

Question 27

What is the treatment for Stage 1) Genetic loading in the inflammatory cascade in asthma?

Answer 27

Avoidance of the trigger

Question 28

What is the treatment for Stage 2) Eosinophilic inflammation in the inflammatory cascade in asthma?

Answer 28

Anti-inflammatories e.g. corticosteroids

Question 29

What is the treatment for Stage 3) Release of allergic mediators in the inflammatory cascade in asthma?

Answer 29

Anti-leukotrienes/histamines and anti-IgE

Question 30

What is the treatment for Stage 4) Twitchy smooth muscle in the inflammatory cascade in asthma?

Answer 30

Bronchodilators to relax the bronchial smooth muscles, or muscarine antagonists to block airway constriction

Question 31

Why are inhaled corticosteroids the mainstay of first line treatment for asthma?

Answer 31

They are the only class of drugs which will converted the anatomical mess of airway inflammation into organised anatomy

Question 32

What are the diagnostic indicators of asthma?

Answer 32

-Reduced forced expiratory ratio (Fev1/FVC

Question 33

What is the inflammatory cascade in the development of COPD?

Answer 33

1) Cigarette smoke or other noxious particles 2) activate resident alveolar macrophages and airway epithelial cells 3) These release cytokines 4) Activation of neutrophils, CD8 T cells, increased macrophage numbers 5) Neutrophils and macrophages release proteases that break down connective tissue in the lung parenchyma and also stimulate hyper secretion 6) Result in chronic bronchitis and emphysema

Question 34

Diagnostic factors of COPD:

Answer 34

- Chronic symptoms (not episodic like asthma) - Smoking - Non-atopic - Daily productive cough - Progressive SOB - Frequent infective exacerbations - Expiratory wheeze from chronic bronchitis - Reduced breath sounds from emphysema

Question 35

What is the progression of disease in COPD?

Answer 35

1) Progressive fixed airflow obstruction 2) Impaired alveolar gas exchange 3) Respiratory failure (decreased PaO2 and Increases PaCO2) 4) Pulmonary hypertension 5) Right ventricular hypertrophy/failure 6) Death

Question 36

What are the main differences between asthma and COPD?

Answer 36

.

Question 37

Asthma vs. COPD: Smoking

Answer 37

Asthma = non-smokers COPD = smokers

Question 38

Asthma vs. COPD: Allergic

Answer 38

Asthma = allergic COPD = non-allergic

Question 39

Asthma vs. COPD: Onset

Answer 39

Asthma = early or late COPD = late

Question 40

Asthma vs. COPD: Symptoms duration

Answer 40

Asthma = intermittent COPD = chronic

Question 41

Asthma vs. COPD: Inflammatory cells involved

Answer 41

Asthma = Eosinophils COPD = Neutrophils

Question 42

Asthma vs. COPD: Diurnal variation

Answer 42

Asthma = Diurnal variaion COPD = None

Question 43

Asthma vs. COPD: Corticosteroid and bronchodilator response

Answer 43

Asthma = Good COPD = Poor

Question 44

Asthma vs. COPD: Progression

Answer 44

Asthma = none COPD =progressive decline

Question 45

Asthma vs. COPD: FVC and TLCO

Answer 45

Asthma = Preserved COPD = Reduced

Question 46

Asthma vs. COPD: Gas exchange

Answer 46

Asthma = Normal COPD = Impaired

Question 47

Asthma vs. COPD: Cough

Answer 47

Asthma = non-productive cough COPD = productive cough

Question 48

What classes as 'brittle asthma'?

Answer 48

Wide PEF variability or sudden attacks when otherwise well controlled

Question 49

What classes 'moderate asthma exacerbation'?

Answer 49

PEF \>50-75% predicted with increasing symptoms but no signs of acute asthma

Question 50

What classes 'acute severe asthma?'

Answer 50

Any one of: - PEF 33-50% predicted - RR\>25/min - HR \>110/min - Inability to complete sentences in one breath

Question 51

What classes 'life threatening asthma'?

Answer 51

Any one of the following seen in acute severe patients: - Altered conscious level - Exhaustion - Arrhythmia - Hypotension - Cyanosis - Silent chest - Poor respiratory effort - PEF

Question 52

What classes 'near fatal asthma'?

Answer 52

Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures

Question 53

How is smoking involved in the pathogenesis of COPD?

Answer 53

## Footnote Smoking-tobacco smoke increases the number of neutrophils and macrophages in the lungs, its slow transit of these cells promotes neutrophil degranulation and inhibits a1-antitrypsin

Question 54

Which 2 coniditons make up COPD?

Answer 54

Chronic bronchitis and emphysema

Question 55

Chronic bronchitis

Answer 55

Cough productive of sputum on most days for 3 months of at least 2 consecutive years. Chronic irritation leads to increased mucus production associated with goblet cell metaplasia, macrophage accumulation and fibrosis around bronchioles generate functional obstruction

Question 56

Emphysema

Answer 56

Increase beyond normal size in distal airspaces to terminal bronchiole due to loss of alveolar walls (tissue destruction) due to protease activity. Emphysema impairs respiratory function –diminished alveolar surface area for gas exchange. Loss of elastic recoil and loss of support of small airways leads to tendency to collapse.

Question 57

Asthma

Answer 57

Chronic inflammatory disorder (eosinophilic infiltration) characterised by hyper-reactive airways leading to episodic reversible bronchoconstriction