L11 - COPD Flashcards
Define COPD
- Characterised by persistent airflow limitation
- usually progressive
- and associated with an enhanced chronic inflammatory response.
Criteria for diagnosis of Chronic bronchitis
cough and sputum for atleast 3 consecutive months for 2 consecutive years.
Emphysema
- Abnormal permanent enlargement of airspace distal to terminal bronchioles.
- Bullae may form.
- Accompanied by the destruction of alveolar walls and without obvious fibrosis.
Why may COPD cause increased sputum production and what is the consequence of this?
- Enlargement of mucus secreting glands.
- Increased number of goblet cells.
- Inflammatory cell infiltrate.
- increased sputum production may lead to chronic bronchitis
Describe the consequence of loss of elastic tissue, inflammation and fibrosis in airway wall:
- Premature airway closure.
- Gas trapping
- Dynamic hyperinflation.
This leads to changes in pulmonary and chest wall compliance.
Systemic features of COPD
- Muscular weakness: reflecting deconditioning (lack of muscle fitness), cellular changes in skeletal muscle.
- Increased circulating inflammatory markers
- Peripheral oedema: impaired salt and water excretion
- Altered fat metabolism contributing to weight loss
- Prevalence of osteoporosis
Describe effects of pulmonary hyperinflation?
- Flattens diaphragmatic muscle
- leads to increased horizontal alignment of intercostal muscles
- respiratory muscles disadvantaged
First symptoms of COPD?
- cough
- associated sputum production
Why do COPD patients often have pitting oedema?
- Salt and water retention
- caused by renal hypoxia and hypercapnia (carbon dioxide retention)
How might we measure lung volume?
Determine hyperinflation.
Generally performed by helium dilution technique.
Limitations of helium dilution technique to measure lung volume?
May underestimate lung volume in those with severe COPD and large bullae.
Hence Body Plethysnography used.
When are oral glucocorticoids given?
- Good for use during exacerberations.
- However not for maintenance therapy
- as may contribute to osteoporosis and impaired skeletal muscle.
State some ways of managing COPD?
Bronchodilators: breathlessness
Oral glucocorticoids
Oxygen therapy
Surgical intervention
When might surgical intervention be required in a patient with COPD?
- bullectomy
- if large bullae compressing surrounding normal lung tissue.
Example of bronchodilator which may be given to patient with COPD?
Nebulished short acting B2 agonist combined with anti-cholingeric agent (salbutamol and ipratropium)