Pathophysiology of COPD Flashcards
COPD inflammation
Immune cells, such as neutrophils and macrophages, are attracted to tissues damaged by tobacco smoke due to acute local inflammation caused by the chemicals in tobacco smoke. When immune cells infiltrate the affected areas, they attempt to resolve the inflammation and repair damaged tissue
Pathological changes in airways
Generate symptoms associated with chronic bronchitis
Pathological changes in the lung tissue and alveoli
Reflected in emphysema
Chronic bronchitis
- Characterised by chronic and excessive sputum production, coughing and airway obstruction.
- Involves impaired airflow through the airways due to reduced airway lumen radius and increased airway resistance.
In chronic bronchitis airway lumen size is reduced by
Excessive mucus secretion, tissue swelling, and degradation of the overall airway structure
Emphysema
- Pathological enlargement of alveolar airspaces due to destruction and degradation of lung tissue. This results in loss of structural fibres such as elastin (increasing compliance) as well as reduced surface area and damage to the pulmonary vasculature (decreasing gas exchange)
Resulting in respiratory failure and symptoms of COPD
What does Chronic hypoventilation of alveoli result in
Prolonged and widespread hypoxic vasoconstriction
What happens in chronic hypoventilation
Constriction of the pulmonary vasculature increases vascular resistance, in turn increasing the force required to pump blood through the system and the pressure of blood within it (pulmonary hypertension). This requires the heart to work harder to maintain normal blood flow against increased resistance, resulting in right heart hypertrophy and worsening efficiency.
Exercise tolerance
- Tolerance is reduced.
- Breathlessness when performing mild exercise, intolerance to almost any physical activity in sever COPD patients due to hypoxaemia, hypercapnia, and acidaemia
