COPD (Therapeutics) Flashcards
How does NICE define COPD?
Characterised by airflow obstruction that is not fully reversible, the airflow obstruction does not change markedly over several months and is usually progressive in the long term
What is COPD predominantly caused by? What can also cause COPD?
Smoking
Occupational exposure
What is classed as an exacerbation?
A rapid and sustained worsening of symptoms beyond normal day-to-day variations
How is airflow obstruction defined?
A reduced FEV1/FVC ratio such that FEV1/FVC is less than 0.7
If FEV1 ≥ 80% of predicted normal…
A diagnosis of COPD should only be made in the presence of respiratory symptoms e.g. breathlessness or cough
What is airway obstruction in COPD caused by?
A combination of airway and parenchymal (functional tissue) damage
This damage is a result of chronic inflammation which differs from that seen in asthma and is usually caused by tobacco smoke
COPD is often…
Undiagnosed
Significant airflow obstruction may be present before a person is even aware of it
COPD may respond to therapies which have little or no impact on…
Airflow obstruction
COPD is now the preferred term for other airflow obstruction conditions previously diagnosed as…
Chronic bronchitis
Emphysema
What is ‘chronic bronchitis’?
Presence of cough and sputum production for at least 3 months in each of 2 consecutive years
Inflammatory process in the bronchi in response to inhaled irritants (usually due to cigarette smoking)
What is ‘emphysema’?
Involves the progressive and destructive enlargement of bronchioles, alveolar ducts and sacs
Leads to loss of surface area available for gas exchange and loss of elastic recoil
What are the 2 types of emphysema?
Centrilobular
Panacinar
What is a COPD diagnosis based on?
History, physical examination and confirmation of the presence of airflow obstruction using spirometry
No single diagnostic test
Early stages of COPD are often…
Asymptomatic
In which patients should a diagnosis of COPD be considered?
Patients over 35 who have a risk factor (generally smoking) and who present with one or more of the following symptoms:
Exertional breathlessness
Chronic cough (productive or unproductive)
Regular sputum production
Frequent winter ‘bronchitis’
Wheeze
Why is it difficult to evaluate sputum production?
Differing patient habits
What does a change in colour or volume of sputum indicate?
Possible exacerbation
For patients in whom a diagnosis of COPD is suspected, they should also be asked about the presence of which factors?
Weight loss Exercise intolerance Waking at night Ankle swelling Fatigue Occupational hazards Chest pain Haemoptysis (blood in mucus)
Patients with a suspected diagnosis of COPD should receive which tests?
Spirometry
A chest radiograph to exclude other pathologies
A FBC to identify anaemia or polycythaemia
BMI calculated
What is the difference in airway obstruction in COPD vs. asthma?
In COPD, airways are permanently damaged and narrowed, therefore symptoms are persistent
In asthma, inflammation of the airways causes constriction, therefore symptoms come and go
What is the difference in reversibility testing in COPD vs. asthma?
In COPD, reversibility following a bronchodilator is only modest
In asthma, expect an increase in lung capacity of ~400ml after using a bronchodilator
What is the difference in cough symptoms in COPD vs. asthma?
Chronic cough with sputum vs. irritating cough
What is the difference in nighttime symptoms in COPD vs. asthma?
Nighttime breathlessness and wheeze that keeps patient awake, not common vs. common
What is the difference in the age groups affected in COPD vs. asthma?
> 35 vs. <35
What is the difference in atopic (genetic) causes in COPD vs. asthma?
Unlikely to be an atopic cause vs. likely
What is the difference in smoking status in COPD vs. asthma?
Nearly all smokers or ex-smokers vs. possibly
Risk of developing COPD is thought to be due to interactions between…
‘Host factors’ and ‘environmental factors’
What are some of the risk factors for developing COPD?
Smoking
Age
Male gender
α1 antitrypsin deficiency
Occupational dusts and chemicals (dependent on intensity and duration of exposure)
Indoor air pollution (burning of open fires of wood, animal dung, coal and agricultural residues)
Existing impaired lung function
Infection (a history of tuberculosis and childhood infections associated with reduced lung function and airway obstruction)
Socioeconomic status (greater smoking prevalence, poorer housing and nutrition)
Nutrition
Asthma
How does smoking contribute to COPD development?
Tobacco smoke causes the releases destructive proteolytic enzymes from inflammatory cells in the lungs, oxidative stress and inactivation of α1 antitrypsin
Dependent on the surrounding context (pack years, age at which smoking was started, maternal smoking and passive smoking )
How does α1 antitrypsin deficiency contribute to COPD development?
α1 antitrypsin is a protein produced mainly in the liver
Its role is to protect the lungs from neutrophil elastase
Lack of α1 antitrypsin results in early and accelerated development of panlobular emphysema
Risk is exponentially higher in smokers
Who does α1 antitrypsin deficiency predominantly affect?
People of Northern European origin
On which factors is COPD graded?
FEV1% Breathlessness (using MRC scale) Symptoms BMI Hypoxia Smoking status Exercise capacity
Which tool is used to assess dyspnoea in COPD?
MRC dyspnoea scale
Which tool is used to assess prognosis in COPD?
BODE index (BMI, airflow obstruction, dyspnoea and exercise capacity) This a 10-point score that assesses disease outcome
