COPD Flashcards
what is COPD
COPD is a preventable and treatable (but not curable) respiratory condition that is characterised by persistent respiratory symptoms and airflow obstruction.
What conditions does COPD encompass? (these are the old terms used to describe COPD)
emphysema and chronic bronchitis
what is emphysema
its a pathological term referring to loss of parenchymal (functional aka helping gas exchange aka alvioli) lung texture
what is chronic bronchiolitis
clinical term referring to cough and sputum production for at least 3 months in each of 2 consecutive yrs
modifiable risk factors of COPD
Smoking - accounts for 90% of COPD cases. cigs but also water pipe, marijuana, and other types
Occupational exposure - coal or silica dust, welding fumes, industrial chemicals etc.
Air pollution
Childhood or in-utero lung damage - maternal or passive smoking, preterm birth, severe respiratory infections.
non modiafiable COPD risk factors
Alpha-1-antitrypsin deficiency - a rare, congenital cause of COPD, present in 2% of COPD cases. It should be considered in those diagnosed under 45 years.
Asthma
what are the key COPD symptoms
cough: often productive
dyspnoea (SOB)
wheeze
a history of recurrent lower resp tract infections
nature and progression of SOB
progresses over time and worse on exertion
other symptoms of COPD
weight loss
fatigue
reduced exercise tolerance
waking at night with dyspnoea
barrel chest (hyperinflation
pursed lip breathing
in severe cases, right-sided heart failure may develop resulting in peripheral oedema
signs on physical examination
- Hyper-resonance on percussion
- End-expiratory wheeze on auscultation
- Coarse crackles
- Reduced breath sounds
What are the key investigations?
spirometry
standardised symptoms score (mMRC/ CAT: latter more detailed but less widely used)
Pulse oximetry
ABG
CXR
FBC
BMI calculation
how to use spirometry data for COPD diagnsosis
1) -post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
2) after obstruction is demonstrated:
-The severity of COPD is categorised using the FEV1*:
FEV1%= observed/ predicted value-
>80% stage 1 mild
50-79= stage 2 moderate, 30-49% stage 3 severe
<30% stage 4 very severe
3) Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
4) symptoms SHOULD be present to diagnose COPD in these patients
what does CXR show
- Hyperinflation (>6 anterior ribs seen above diaphragm)
- Bullae- If large may mimic a pneumothorax
- Hyperlucent lung fields
- Flat hemidiaphragm
- can exclude lung cancer
Alpha-1-antitrypsin levels- when do we do this?
If young patient, who has never smoked
What would we see on CT for A1AT deficiency and how does this differ to COPD?
would see Emphysema in lower lobes while COPD has upper lobe emphysema
why do we do an FBC as an investigation for COPD?
Exclude secondary polycythaemia