L11 - COPD Flashcards
What is chronic obstructive pulmonary disease (COPD)?
A preventable and treatable disease characterised by progressive air-flow limitation, associated with abnormal inflammatory response
What two factors lead to the airflow limitation seen in COPD?
Small airway disease (chronic bronchitis) Parenchymal destruction (emphysema)
Where does airflow limitation occur in COPD?
Small airways (bronchi and bronchioles <2mm)
What occurs in parenchymal destruction (emphysema)?
Loss of alveolar attachments and decrease of elastic recoil
What occurs in small airway disease (chronic bronchitis)?
Mucosal inflammation and fibrosis, mucus plugs
What is emphysema?
Damage and destruction of alveolar sacs (parenchymal destruction)
What is an informal name for someone with emphysema? Why is this?
Pink puffers - no cyanosis (blue colouration), hyperventilate to produce normal blood gases
What manifestations can be seen in emphysema?
Tissue destruction, low elastic recoil in lungs, air becomes trapped causing an increased residual volume
What is chronic bronchitis?
Chronic inflammatory condition that causes swelling and irritation of respiratory tract and build up of mucus (small airway disease)
What is an informal name for someone with chronic bronchitis? Why is this?
Blue bloater - cyanosis (blue skin colouration) and peripheral oedema or overweight
What manifestations can be seen in chronic bronchitis?
Chronic cough for at least 3 months per year for 2 years, thick mucus, decreased lung capacity
What can chronic bronchitis result in?
Right heart failure and chronic pulmonary hypertension
What is the main risk factor for developing COPD?
Smoking
Give five risk factors for developing COPD
Smoking, exposure to particles (dust, work environment…), genetics, sex (female), age (usually 50-60)
What is a major genetic cause of COPD? What is the likely prognosis for these people?
Alpha1-antitrypsin (AAT) deficiency
AAT deficient people develop COPD 20-30 years earlier, especially if they also smoke
How does α1-antitrypsin deficiency cause destruction of the lung?
AAT is an anti-protease (suppresses proteases); AAT deficient people have more protease activity, resulting in more breakdown of tissues
What is asthma–COPD overlap syndrome (ACOS)?
There is no clear definition, but it is a coupling of COPD and asthma, and has been used to explain why some patients respond well to corticosteroids
What is the main cell involved in COPD?
Neutrophil
What role does the neutrophil play in COPD?
It produces proteases (neutrophil elastase, MMP8, MMP9) that contribute to emphysema and mucus secretion, and reactive oxygen species that are involved in inflammation
What technique is used to diagnose COPD? What does this involve?
Spirometry - patient breathes into spirometer to carry out lung function tests
Give three of the main lung function test parameters
FEV1 - volume forcibly expired in 1st second
FVC - total volume forcibly expired
FEV1/FVC ratio
RV - volume of residual air after maximum exhalation
PEF - peak expiratory flow
TLC - total lung capacity at full inhalation
TV - tidal volume, volume in/exhaled at rest
What lung function test parameters are decreased in COPD?
FEV1, FVC, PEF, TV
What lung function test parameters are increased in COPD? Why is this?
RV and TLC as air is trapped in the lungs
FEV1 declines naturally with age, more so in smokers. If someone were to stop smoking, what would happen to their FEV1?
It would still decline with age, but would be more gradual than if they had continues smoking
