Obstructive Airway Diseases

Question 1

Name the three main obstructive airway diseases

Answer 1

• chronic bronchitis
• emphysema
• asthma

Question 2

What is COPD

Answer 2

chronic bronchitis and emphysema; very rare to have one without the other

Question 3

What is PEFR

Answer 3

the peak rate of flow in one second that indicates airway obstruction when below 50% of the best value

Question 4

How can COPD be detected in spirometry

Answer 4

• there is airflow limitation
• PEFR is reduced
• FEV1 is reduced
• FVC may be normal
• FEV1/FVC is less than 70%

Question 5

What is asthma in terms of inflammation

Answer 5

type 1 inflammation in the airways - mast cell degranulation/histamine/IgE…

Question 6

What are the main causes of COPD

Answer 6

• smoking
• atmospheric pollution
• occupation (dust)
• emphysema alone; alpha-1-antitrypsin deficiency

Question 7

How is chronic bronchitis defined clinically

Answer 7

cough with sputum most days in at least three consecutive months for two or more consecutive years

Question 8

What is complicated chronic bronchitis

Answer 8

bacterial bronchitis/bronchopneumonia is interfering with the chronic bronchitis, making it mucopurulent

Question 9

What are the effects of chronic bronchitis on larger airways

Answer 9

• mucous gland hyperplasia
• goblet cell hyperplasia
• minor inflammation/fibrosis

Question 10

What are the effects of chronic bronchitis on smaller airways

Answer 10

• appearance of goblet cells where normally absent

- inflammation and fibrosis in long standing disease

Question 11

How is emphysema defined pathologically

Answer 11

an increase in the size of the airways distal to the terminal bronchioles due to dilatation or destruction of their walls

Question 12

What are the three types of emphysema

Answer 12

• centriacinar
• panacinar
• periacinar

Question 13

What is centriacinar emphysema

Answer 13

• destruction closest to the terminal bronchiole

- most common as here material is deposited due to the change to gaseous diffusion

Question 14

What part of the lung does centriacinar emphysema affect and why

Answer 14

• the upper lobe

- clearance mechanisms are less effective here because there are less alveolar macrophages due to a smaller blood supply

Question 15

What is panacinar emphysema

Answer 15

destruction of large areas covering the entire lung

Question 16

What is periacinar emphysema

Answer 16

• destruction of areas at the edge of the acinii where they come into contact with pleural membrane
• bulla = an emphysematous space greater than 1cm, can burst causing spontaneous pneumothorax

Question 17

Describe how smoking contributes to the protease/antiprotease imbalance

Answer 17

• smoking reduces anti-elastase levels and increases elastase levels
• smoking reduces the repair mechanisms of elastin synthesis
• leads to tissue destruction associated with emphysema

Question 18

What components of COPD may respond to pharmacological intervention

Answer 18

• smooth muscle tone

- inflammation

Question 19

In physiology, what prevents the smaller airways collapsing during the increase in pressure that comes with expiration

Answer 19

the elastic alveolar walls they are attached to prevent the collapse

Question 20

How is this different in COPD

Answer 20

• the alveolar walls are destroyed, therefore the smaller airways cannot remain open long enough to allow a full expiration