Emphysema

Question 1

What type of condition is Emphysema?

Answer 1

Chronic, obstructive, inflammatory condition

collapsed airways cause blockage

Question 2

What are the risk factors for emphysema?

Answer 2

Smoking
Men
Lower Socioeconomic Class
Living in an urban environment
Air pollution, coal durst, grain dust

Question 3

How does smoking increase the risk of emphysema?

Answer 3

Irritants in smoke cause activation of the inflammatory response

Question 4

Why is emphysema associated with lower socioeconomic class?

Answer 4

Higher exposure to inhaled pollutants

Question 5

Why is emphysema more common in men?

Answer 5

Tend to work in environments with higher occupational exposure to irritants

Question 6

How can emphysema be defined?

Answer 6

Permanent enlargement of the airspaces distal to the terminal bronchioles

Question 7

What is the effect of emphysema on airflow?

Answer 7

Two mechanisms:

• loss of the alveolar walls –> decreased elastic recoil –> airflow limitation
• Loss of alveolar supporting structure –> airway narrowing

Question 8

\what is centriacinar emphysema?

Answer 8

Focal destruction limited to respiratory bronchioles and central acini

• assosiated with smoking
• worse in the upper lobes

Question 9

What is paracinar emphysema?

Answer 9

destruction of the distal airway structures, alveolar ducts and sacs

• assosiated with alpha-1 aantritrypsin deficiency
• more severe in the lower lobe but spreads throughout the entire lung

Question 10

how does smoking cause emphysema?

Answer 10

Inaheld irritants from the cigarette smoke causes an inflammatory response

Increased numbers of luekocytes and macrophages release elastin

Elastin is responsible for the normal turn over of elastase in the alveolar wall
- this is usually counteracted by alpha-1 antitriptase which destroys elastin

In smoking, there is increased elastase production, and decreased sythesis and action of alpha-1 antitripase

This results in destruction of the alveolar walls by the breakdown of elastic tissue and collagen

Question 11

What is the effect of emphysema on collateral ventilation?

Answer 11

Loss of supporting structure around the alveoli leads to collapse of the small airways during exhalation

The channels of martin (interbroncholar), and channels of lambert (bronchiole-alveolar) collapse and mean that air can become more easily trapped in the distal airways

Erosion of the alveolar septa means there is a loss of the pores of kohn (between alveoli)

Question 12

What is the first clinical presnetation of Emphysema?

Answer 12

Gradual onset of breathlessness - patients usually ignore symptoms and manage breathlessness with lifestyle modificaitons

Question 13

What would ABGs show in emphysema?

Answer 13

mild to moderate hypoxemia without hypercapnia

Question 14

What is the effect of emphysema on the elastic recoil mechanism?

Answer 14

In normal funciton, peripheral airways rely on the surrounding alveoli to maintain patency, as there is no cartilige present. During exhilation, the elastin recoils to force air out but patency is maintained by supporting structures

In emphysema, there is a loss of elastin which means loss of elastic recoil
Loss of elastic recoil –> air remains in alveoli

More pressure is required to try and get the air out of the lungs, but since there is destruction supporting structures which keep the airways open when there is high pressure, there is collapsing of the terminal bronchiole

Air becomes trapped in the distal airways and there is hyper-inflation