Chronic Obstructive Pulmonary Disease (COPD) Flashcards
What is COPD?
A chronic, slowly progressive disorder characterised by airflow obstruction that does not change markedly over several months. Most of the lung function impairment is fixed, although some reversibility can be produce by bronchodilator (or other) therapy.
What is important to note about the definition of COPD?
Defined by airflow obstruction.
NO mention of symptoms, chronic bronchitis, emphysema or smoking.
What causes airway obstruction in COPD?
Small-airway narrowing and can be worsened by inflammation and mucus (increased no. of goblet cells). Also get thickening of airway walls, loss of elasticity and disrupted alveolar attachments. Lymphoid follicles in severe disease.
What do the vast majority of people in COPD have?
Chronic bronchitis and emphysema.
Some only have emphysema and this is due to a genetic component - alpha 1-antitrypsin deficiency.
What is the prevalence of COPD like in the UK?
1.2 mil diagnosed
50% of total no of COPD patients diagnosed
Total prevalence approx. 1.5-2 mil.
Male predominance and increasing prevalence.
Why can COPD be called a disease of social deprivation?
Affects those in social deprivation as they are more likely to smoke/lower education.
COPD is the —th most common cause of death in the UK.
6th
(5th most common WW).
By 2030, will be third leading cause of death.
What burden does COPD have on the NHS?
Responsible for 1.5% of all acute hospital admissions (164, 000 admissions, 1, 300, 000 bed days).
10% acute admissions due to COPD.
15% of COPD patients admitted per year.
86% are exclusively primary care.
On average each COPD patient visits GP 6-7 per year.
How does COPD affect the patient?
Ranges depending on severity of COPD. May cause difficulty climbing stairs, gardening, housework, dressing and sleep disturbance.
What is the majority of COPD attributable to?
85% COPD attributable to smoking.
What are some other less common causes of COPD?
Chronic asthma
Passive smoking
Maternal smoking (reduces FEV1 and increases resp illness)
Air pollution (prevalence of COPD increased with air pollution)
Occupation - jobs exposing to dusts, vapours and fumes (e.g. coal mining, hard rock mining, tunnel working, concrete manufacturing, construction, farming, foundry working, plastics, textiles, rubber, leather…).
a1-antitrypsin deficiency.
What is the role of a1-antitrypsin?
Produced in the liver, circulates in the blood and particularly important in the lungs. When you breathe in cig smoke you kill off neutrophils, neutrophils release a lot of prolytic enzymes which can cause COPD. a1-AT neutralises neutrophil enzymes and protects the lungs.
What is a1-antitrypsin deficiency?
75 different variants (normal genotype 86% UK - PiMM and troublesome genotype PiZZ (10-20% MM).
PiZZ accounts for 0.03% of population (not all COPD).
People with this develop COPD at a very young age.
E.g.
Non-smokers with this develop dyspnoea @ 51 yrs, and die @ 67 yrs.
Smokers with this develop dyspnoea @ 32 yrs and die @ 48 yrs.
How many smokers develop clinically significant COPD? Subclinical airflow obstruction? Never develop any significant airflow obstruction?
Cig smoking is clearly the single most important identifiable aetiological factor in COPD.
Only 20% of smokers develop clinically significant COPD.
30% significant but subclinical airflow obstruction.
50% never develop significant airflow obstruction.
How much COPD develop in non-smokers?
Asthma, a1-AT deficiency.
