Obstructive Airways Diseases

Question 1

What are some symptoms of obstructive airway syndromes?

Answer 1

Asthma
Chronic bronchitis
Emphysema - over-inflation of alveoli

Question 2

What is asthma?

Answer 2

An airway inflammation of both the large and small airways

Question 3

What does the bronchial tree consist of?

Answer 3

23 levels of branching

First 16/17 branches play no part in gas exchange and therefore are referred to as the conducting zone

Question 4

What is the conducting zone used for?

Answer 4

To transport inhaled air into the remaining 6/7 branches

Question 5

What is the acinar zone?

Answer 5

Includes the bronchioles, alveolar ducts and alveolar sacs and they take part in gas exchange

Question 6

What are the airways like in COPD?

Answer 6

Thick alveolar wall, thin layer of smooth muscle, a thick layer of mucosa and a relatively small lumen diameter

Question 7

What terms can be used to describe asthma?

Answer 7

Early/late onset
Atopic/non-atopic
Extrinsic/intrinsic

Question 8

What is the asthma triad?

Answer 8

Reversible airflow obstruction
Airway inflammation
Airway hyper-responsiveness

Question 9

What is the dynamic evolution of asthma?

Answer 9

Bronchoconstriction = brief symptoms
Chronic airway inflammation = exacerbations
Airway remodelling = fixed airway obstruction

Question 10

What are the histological hallmarks of airway remodeling in asthma?

Answer 10

Thickening of basement membrane
Collagen deposition in the submucosa
Hypertrophy of the smooth muscle

Question 11

What is the inflammatory cascade in asthma?

Answer 11

An inherited or acquired factor is needed to set of eosinophilic inflammation. TH2 cytokines and mediators are then released that cause the smooth muscle to become twitchy and hyper-reactive

Question 12

What can be used to treat the inherited or aquired part of the inflammatory cascade?

Answer 12

To avoid the precipitant such as an allergen that activates the inflammation cascade and triggers asthma in the patient

Question 13

What can be used to treat eosinophilic inflammation?

Answer 13

Anti-inflammatory medications such as:
Corticosteroids
Cromones
Theophyline

Question 14

What can be used to prevent the mediators or TH2 cytokines from acting?

Answer 14

Antileukotrines or antihistamines
Monoclonal antibodies such as:
Anti-IgE
Anti-interleukin-5

Question 15

What can be used to treat the twitchy smooth muscle hyper-reactivity?

Answer 15

Bronchodilators such as:
Beta2-agonists
Muscarinic antagonists

Question 16

What is the clinical syndrome of asthma?

Answer 16

Episodic symptoms and signs 
Diurinal variability 
Non-productive cough 
Triggers 
Associated atopy - increased IgE 
Blood eosinophils above 4% 
Responsive to steroids or beta-agonists 
Family history of asthma 
Wheezing due to turbulent flow

Question 17

What attracts eosinophils to the airways?

Answer 17

IL-5

Question 18

What do mast cell release when IgE binds to them?

Answer 18

Histamine which causes excess mucus secretions and vasoconstriction

Question 19

What do basophils release when IgE binds to them?

Answer 19

Leukotrine D4 which induces bronchoconstriction

Question 20

How is asthma diagnosed?

Answer 20

History and examination 
Diurinal variation of peak flow rate
Reduced FEV1/FVC ratio
Reversibility to inhaled salbutamol 
Provocation testing - bronchospasm such as exercise or histamine/methacholine/mannitol

Question 21

What are the components of COPD?

Answer 21

Mucociliary dysfunction
Tissue damage
Inflammation

Question 22

What is the disease process in COPD?

Answer 22

Exposure to inhaled noxious particles (smoking) which causes inflammation of the lungs that can lead to COPD is the normal protective and repair mechanisms are overwhelmed

Question 23

What can cigarette smoke activate in airways?

Answer 23

Macrophages and airway epithelial cells in the resp tract which will release neutrophil chemotactic factors such as IL-8 and leukotrine B4

Question 24

What do neutrophils and macrophages release?

Answer 24

Proteases that break down connective tissues in the lung parenchyma and also stimulates mucus secretion. They are usually counteracted by protease inhibitors such as SLPI and tissue inhibitors of matrix metalloproteinases

Question 25

What characterizes chornic bronchitis?

Answer 25

Chronic neutrophilic inflammation 
Mucus hypersecretion 
Mucociliary dysfunction 
Altered lung biome 
Smooth muscle spasm and hypertrophy

Question 26

What charcterizes emphysema?

Answer 26

Alveolar destruction
Impaired gas exchange
Loss of bronchial support
It is irreversible

Question 27

How do you assess COPD?

Answer 27

Assess symptoms
Assess degree of airflow limitation using spirometry
Assess risk of exacerbations
Assess comorbidities
Two exacerbations or more within the past year or a FEV1 <50% than predicted are indicators of high risk

Question 28

What is the clinical syndrome of COPD?

Answer 28

Progressive fixed airflow obstruction 
Impaired alveolar gas exchange 
Respiraotry failure : Reduced PaO2 and increased PaCO2
Pulmonary hypertension 
Right ventricular hypertrophy/failure
Death

Question 29

What are the non-pharmacological managements of COPD?

Answer 29

Smoking cessation
Immunisation against influenza and pneumococcal
Physical activity
Oxygen

Question 30

What are the pharmacological managements of COPD?

Answer 30

LAMA or LABA
LABA/LAMA combo
ICS/LABA combo
ICS/LABA/LAMA combo