COPD Flashcards
What is COPD?
COPD is characterised by airflow obstruction. The airflow obstruction is usually progressive, not fully reversible and does not change markedly over several months. This disease is predominantly caused by smoking.
What is COPD an umbrella term for?
Emphysema and Bronchitis
What is emphysema?
Pathological process in which there is destruction of the terminal bronchioles and distal airspaces
This leads to loss of the alveolar surface area and therefore impairment of gas exchange.
It often progresses to the development of larger redundant airspaces called bullae within the lung.
Also destruction of supporting tissues surrounding the small airways. This means they collapse during expiration when the pressure outside the airways rises.
This results in airflow obstruction particularly affecting the small airways.
Also destruction of elastic tissue - hyperinflation of the lungs as they are unable to resit the natural tendency of the rob cage to expand outwards.
What is chronic bronchitis?
Chronic mucus hyperexcretion that commonly occurs in smokers.
Mucus hyper secretion is caused by inflammation in the large airways leading to proliferation of mucus producing cells in the respiratory epithelium.
The result is a chronic productive cough and frequent respiratory infections. In COPD, this frequently persists even after smoking has stopped.
Chronic bronchitis results in airflow obstruction due to remodelling and narrowing of the airways.
What are some causes of COPD?
Smoking (90% of cases)
Alpha-1-antitrypsin deficiency
Occupational exposure - coal dust
Pollution
Do all smokers develop COPD?
Approximately 15% of smokers will develop COPD
What are the symptoms of COPD?
Cough and sputum production. Although many don’t present until breathless
Breathlessness is often progressive
Exacerbations are associated with increased breathlessness and cough and sputum production -may be infective.
What is the MRC Dyspnoea score?
This is a score used to characterise breathlessness in relation to activities.
- Not troubled by breathlessness except on strenuous exercise
- Short of breath when hurrying or walking up a slight hill
- Walks slower than contemporaries on level ground because of breathlessness, or has to stop for breath when walking at own pace.
- Stops for breath after walking about 100m or after a few minutes on level ground.
- Too breathless to leave the house, or breathless when dressing or undressing
What are the signs of breathlessness?
Sometimes no signs
“Purse lip” breathing - protective manoeuvre to increase pressure within airways causing a reducing / delay in closure of airways
Tachypnoea
Using accessory muscle
Hyperinflation - diaphragm and other respects muscles working harder to ventilate lungs.
Wheeze or quiet breath sounds
Cyanosis, CO2 retention, right heart failure, with oedema
How does the spirometer of a COPD patient present?
FEV1 <80% predicted and FEV1/FVC ratio <70%.
This is an obstructive patter.
This is because there is limitation to the flow of air during expiration and therefore volume of air expired in the first second.
Made worse by airway collapse on expiration.
How can spirometry be used in COPD?
Diagnosis and severity of airflow obstruction.
Staging is used to categorise severity.
Mild = FEV1 - 50-80% Moderate = FEV1 - 30-49% Severe = FEV1 - <30%
How do you diagnose COPD?
Combination of signs, symptoms and spirometry (FEC1/FVC <70%).
Following features are suggestive of COPD:
- Smoker / ex-smoker
- Older and symptoms later
- Chronic productive cough
- Persistent and progressive breathlessness.
What other investigations can be done if suspect COPD?
Chest X-ray - exclude other diagnosis
HRCT - macroscopic alveolar destruction in emphysema.
ABG - respiratory failure
Alpha-1-antitrypsin blood test (younger people)
How common is COPD?
Common - 1 million people have COPD and often present between ages of 50-60yrs old.
How do you treat stable COPD?
'COPD care bundle' Stop smoking Pulmonary rehabilitation Bronchodilators Antimuscarinics Steroids Mucolytics Diet -supplement and review Supportive - flu vaccine
Long term oxygen therapy and lung volume reduction can be done if appropriate.
