COPD Physiology and Pathophysiology

Question 1

COPD Definiton

Answer 1

Chronic obstructive pulmonary disease (COPD) is the name for a collection of lung diseases characterised by airway obstruction. The two main conditions under COPD are chronic bronchitis and emphysema

Question 2

COPD - Chronic Bronchitis

Answer 2

Bronchitis is characterized by inflammation of the bronchial tubes (bronchi).
Chronic bronchitis is associated with excessive tracheobronchial mucus production sufficient to cause cough with expectoration for 3 or more months a year for at least 2 consecutive years. The alveolar epithelium is both the target and the initiator of inflammation in chronic bronchitis.
Chronic bronchitis may result from a series of attacks of acute bronchitis, or it may evolve gradually because of heavy smoking or inhalation of air contaminated with other pollutants in the environment.

Question 3

COPD - Emphysema

Answer 3

Emphysema is a pathological diagnosis defined by permanent enlargement of airspaces distal to the terminal bronchioles. This leads to a dramatic decline in the alveolar surface area available for gas exchange.
Furthermore, loss of alveoli leads to airflow limitation by 2 mechanisms.
1. loss of the alveolar walls results in a decrease in elastic recoil, which leads to airflow limitation.
2. loss of the alveolar supporting structure leads to airway narrowing, which further limits airflow.
Emphysema commonly presents with chronic bronchitis.

Question 4

Causes of COPD Exacerbation

Answer 4

Causes of exacerbation of COPD: 
o	Viruses incl rhinovirus (common cold), and influenza
o	Influenza
o	Pollutants 
o	Allergens