COPD: Emphysema

Question 1

Definition

Answer 1

Where the alveolar air sacs became damaged or destroyed which causes alveoli to enlarge and lose their elasticity (causes problems exhaling which depends heavily on the recoil of the alveoli)
Defined by structural changes (enlargement of the air spaces)

Question 2

Pathophysiology

Answer 2

Smoking activates polymorphonuclear leukocytes + inactivates alpha-1 antitrypsin which increases the action of elastases which breakdown elastic tissue to cause emphysema
Problems with exhilaration:
- the airways collapse + do not stay open = air trapping in alveoli.
- lungs more compliant = airway stretches on inhalation + hold onto air + do not allow proper exhilaration.
Loss of elastin also causes breakdown of thin alveolar walls (called septa). Without the walls, neighbouring alveoli coalesce reducing the surface area for gas exchange.

Question 3

A1ATD

Answer 3

Autosomal dominant inheritance
A1AT = degrades neutrophil elastase = protects excessive damage to elastin layer esp in lungs.
Deficiency (lower liver production) = increase NE = pan acinar emphysema and liver issues.
Suspect in younger/middle age men with COPD symptoms BUT NO SMOKING Hx

Question 4

Types of emphysema

Answer 4

Centri-acinar emphysema (MC) = only affects central or proximal alveoli of the acinus (usually the respiratory bronchioles) while the distal alveolar ducts and alveoli are spared.
- seen in smokers
- affects upper lobes of the lungs
Pan-acinar emphysema (LC) = whole acinus is affected down to the alveoli. Associated with alpha 1 antitrypsin deficiency
- affects lower lobes of the lungs
Para-septal emphysema = distal alveoli. Ballooned out alveoli can rupture + cause pneumothorax
Irregular emphysema = involves the acinus irregularly (or patchily) by scarring/fibrosis

Question 5

Signs

Answer 5

Pursed lip breathing (PINK PUFFERS)
Barrel shaped chest = air trapping + hyperinflation
Imaging:
- Increased anterior-posterior diameter
- Flattened diaphragm
- Increased lung field lucency (due to more air trapping)
Downward displacement of liver due to hyperexpansion lungs

Question 6

Symptoms

Answer 6

Signs of CO2 retention
Dyspnoea
Cough
Weight loss

Question 7

Complications

Answer 7

Pneumothorax = seen in para-septal emphysema
Cor pulmonale + RSHF