COPD Flashcards
What is COPD characterized by?
Airflow obstruction that is usually progressive and not fully reversible, doesn’t change markedly over months
What are the 2 diseases encompassed in COPD?
- Chronic bronchitis
- Emphysema
(can have either or both)
What characterizes Emphysema?
Destruction of the terminal bronchioles and distal airspaces leads to loss of alveolar SA
What occurs as a result of the destruction of terminal bronchioles and distal airpspaces in emphysema?
Destruction of tissues…
a) removes scaffolding support of small airways which makes them collapse leading to obstruction
b) increases compliance: reducing lung recoil leading to hyperinflation
Is emphysema an obstructive or restrictive disease and why?
Obstructive due to the loss of tissue scaffolding and subsequent collapsing of smaller airways
What are bullae and when do they form?
Permanent air filled spaces within lung parenchyma with a thin/poorly defined wall formed during emphysema
What are the 2 types of emphysema?
- Centrilobular: primarily upper lobes, occurs with loss of resp. bronchioles in proximal portion of acinus with sparing of distal alveoli
- Panlobular: Involves all lung fields, especially the bases
What characterizes chronic bronchitis?
Inflammation in larger airways leads to chronic mucus hyper-secretion, this causes re-modelling and narrowing of airways
What are 3 symptoms of chronic bronchitis?
- Chronic productive cough
- Frequent infections (damage to mucociliary escalator)
- Progressive breathlessness and increasing frequent exacerbations
What is the main cause of COPD, and what are 3 other causes?
- Smoking
- Alpha-1-antitrypsin deficiency: no inhibitor of trypsin means neutrophil elastase is constantly activated causing persistent lung tissue damage
- Occupational exposure
- pollution
Explain the MRC Dyspnoea score
Grade of breathlessness
1: not troubled except during hard exercise
2. Short of breath when hurrying or walking up slight hill
3. walks slower than contemporaries on level ground due to breathlessness
4. Stops for breath after walking 100m or so
5. Too breathless to leave house, dress, etc
What are 5 signs of COPD?
- Pursed lips: increases the pressure in airways to force them open
- Tachypnoea
- Use of accessory muscles
- Hyperinflation: air trapping
- May have wheeze or quiet breath sounds
As the disease advances what 3 things are likely to occur?
- CO2 retention
- Cyanosis
- R heart failure
What is the predicted percentage of FEV1 in mild, moderate and severe airflow obstruction?
Mild: 50-80% predicted
Moderate: 30-49% predicted
Severe: <30% predicted
How would you diagnose COPD?
Combination of suggestive symptoms and signs with at least mild airflow obstruction (spirometry)