What is Chronic Obstructive Pulmonary Disease (COPD)?
A chronic, slowly progressive disease disorder characterised by airflow obstruction, which does not charge markedly over several months
What is the effect of airflow obstruction on FEV1?
- Reduced FEV1
- Reduced FEV1/FVC ratio
What causes COPD?
The abnormal inflammatory response of the lung to noxious particles or gases
Where can noxious particles or gases come from?
- Cigarette smoke
- Atmospheric pollutants
What components of cigarette smoke cause lung inflammation?
- Biomass particles
What can make the inflammation caused by cigarette smoke worse?
- Host factors
- Amplifying mechanisms
How does lung inflammation from cigarette smoke cause COPD?
- Oxidative stress
What attempts to protect against oxidative stress?
What attempts to protect against the action of proteinases?
- Repair mechanisms
What is a much less common cause of emphysema?
Inherited deficiency of α1-antitrypsin
What are the symptoms of COPD?
- Productive cough
What does the productive cough in COPD produce?
White or clear sputum
What does COPD usually follow?
Many years of smokers cough
What are the signs of COPD?
- May be no signs
- Quiet wheezes
- Hyperventilation with prolonged expiration (in prolonged disease)
- Accessory muscles of respiration used
- Hyperinflation of the lungs
Why is there hyperventilation with prolonged expiration in COPD?
Expiratory airflow limitation
What factors are considered when assessing COPD?
- Chest X-ray
- Other lung function tests
- High resolution CT scan
What must the history include when assessing COPD?
The MRC dyspnoea scale
What would constitute grade 1 on the MRC dyspnoea scale?
Not troubled by breathlessness except on strenuous exercise
What constitutes grade 2 on the MRC dyspnoea scale?
Short of breath when hurrying or walking up a slight hill
What constitutes grade 3 on the MRC dyspnoea scale?
Walks slower than contemparies on level ground because of breathlessness, or has to stop for breath when walking at own pace
What constitutes grade 4 on the MRC dyspnoea scale?
Stops for breath after walking about 100m, or after a few minutes on level ground
What constitutes grade 5 on the MRC dyspnoea scale?
Too breathless to leave the house, or breathless when dressing or undressing
What other lung function tests are carried out to assess COPD?
- Lung volumes
What is the purpose of a chest x-ray in the assessment of COPD?
Not really to diagnose COPD, mainly to make sure they don't have something else, e.g. cancer
What is the purpose of a high resolution CT scan in the assessment of COPD?
What happens in spirometry?
The patient fills their lungs from the atmosphere, and breathes out as far and fast as possible through a spirometer
What does simple spirometery allow for?
Measurement of many lung volumes and capacities
What is the purpose of oxygen therapy?
To increase oxygen saturation and alleviate symptoms
What is oxygen therapy a treatment for?
Hypoxaemia, not breathlessness
What are the advantages of oxygen therapy?
- Long term