Pathophysiology of COPD

Question 1

Define chronic obstructive pulmonary disease (COPD)

Answer 1

respiratory disease : chronic bronchitis + emphysema.

long-term, progressive, accelerated decline in respiratory function

Question 2

What are 90% of cases associated with?

Answer 2

long term, repeated respiratory exposure to tobacco smoke

Question 3

What are 10% of cases associated with?

Answer 3

exposure to pollution, chemicals, genetic disorders (∝-1-antitrypsin deficiency)

Question 4

What’s the percentage of long term smokers that develop COPD?

Answer 4

30%

Question 5

What are the harmful chemicals in tobacco smoke?

Answer 5

butane,toluene,nicotine,acetic acid,methanol,acetone,cadium,CO,arsenic,benzene,ammonia,stearic acid,hexamine

Question 6

Why is tobacco smoke harmful?

Answer 6

• chemicals cause acute damage to respiratory tissue –>inflammatory response
• repeated, long-term exposure, inflammation becomes chronic, pathological, irreversible injury, dysfunction

Question 7

What do immune cells do in response to inflammation due to tobacco smoke?

Answer 7

• neutrophils + macrophages, attracted to acute local inflammation on tissue
• infiltrate + release proteolytic enzymes

Question 8

Role of proteolytic enzymes?

Answer 8

breakdown dead cells + kill invading organisms

Question 9

Why do immune cells mechanisms become pathological with chronic smoke exposure?

Answer 9

-constant cycles of damage, incomplete/faulty tissue
repair (fibrosis)
-balance between proteases + anti-proteases disrupted

Question 10

How’s mucociliary clearance impaired?

Answer 10

increased mucus secretion + damage to cilia

Question 11

Define chronic bronchitis

Answer 11

long-term inflammation of the bronchi/airways characterised by chronic,excessive sputum production, coughing,airway obstruction

Question 12

How does coughing + mucus production happen?

Answer 12

inflammation within airway tissue, activates sensory neurons stimulating mucus glands

Question 13

What’s the airway dysfunction caused by in chronic bronchitis?

Answer 13

excessive mucus secretion, tissue swelling, degradation of airway structure

Question 14

Why does the airway collapsing entirely when placed under excessive p for bronchitis?

Answer 14

degradation of airway structure

Question 15

Why don’t β2 agonist bronchodilators work for COPD?

Answer 15

This relaxes airway smooth muscle but COPD is mostly caused by excessive mucus secretion, tissue swelling, degradation of airway structure

Question 16

What’s emphysema?

Answer 16

pathological enlargement of alveolar airspaces due to
destruction, degradation of lung tissue –>loss of
elastin (increasing compliance),reduced SA, damage to
pulmonary vasculature (decreasing gas exchange)

Question 17

How does COPD lead to heart failure?

Answer 17

• chronic alveolar hypoxia
• hypoxic vasoconstriction-increased pulmonary resistance
• hypertension
• Increased R ventricular afterload→ RV hypertrophy
• R heart failure

Question 18

How does COPD lead to fatigue?

Answer 18

• chronic alveolar hypoxia
• hypoxaeima, hypercapnia, acidemia
• decreased exercise tolerance
• fatigue
• ↓quality of life

Question 19

How does COPD lead to disability?

Answer 19

hypoxaemia + acidosis

Question 20

What are acute exacerbations characterised by?

Answer 20

temporary but drastic decline in symptoms + respiratory function caused by acute inflammation from infection