Chronic Obstructive Pulmonary Disease Flashcards
What is chronic obstructive pulmonary disease?
Chronic obstructive pulmonary disease (COPD) is a common progressive disorder characterised by airway obstruction with little or no reversibility.
How is chronic bronchitis defined?
Chronic bronchitis is defined clinically as cough and sputum production on most days for 3 months of 2 successive years.
How is emphysema defined?
Emphysema is defined histologicaly as enlarged air spaces distal to terminal bronchioles, with destruction of alveolar walls.
Symptoms of COPD
- chronic shortness of breath
- cough
- sputum production
- wheeze
- recurrent respiratory infections, particularly in winter
Signs of COPD
- tachypnoea
- use of accessory muscles of respiration
- hyperinflation
- cyanosis
- cor pulmonale
- ↓ cricosternal distance (<3cm)
- ↓ expansion
- resonant or hyperresonant to percussion
- quiet breath sounds
- wheeze
What differential diagnosis of COPD should always be considered?
- lung cancer
- fibrosis
- heart failure
What are the 5 points on the MRC (Medical Research Council) Dyspnoea Scale?
Grade 1 – Breathless on strenuous exercise
Grade 2 – Breathless on walking up hill
Grade 3 – Breathless that slows walking on the flat
Grade 4 – Stop to catch their breath after walking 100 meters on the flat
Grade 5 – Unable to leave the house due to breathlessness
How is COPD diagnosed?
Diagnosis is based on clinical presentation plus spirometry
Spirometry will show an “obstructive picture”
forced expiratory volume in 1 second (FEV1) is worse than forced vital capacity (FVC)
FEV1/FVC ratio <0.7
The obstructive picture does not show a dramatic response to reversibility testing with beta-2 agonists such as salbutamol during spirometry testing.
How would you grade severity of airflow obstruction?
Stage 1: FEV1 >80% of predicted
Stage 2: FEV1 50-79% of predicted
Stage 3: FEV1 30-49% of predicted
Stage 4: FEV1 <30% of predicted
Other investigations that can be considered for COPD
- Full blood count for polycythaemia or anaemia. Polycythaemia (raised haemoglobin) is a response to chronic hypoxia.
- Serum alpha-1 antitrypsin to look for alpha-1 antitrypsin deficiency. Deficiency leads to early onset and more severe disease.
- Chest xray hyperinflation, flat hemidiaphragms, large central pulmonary arteries, ↓ peripheral vascular markings, bullae
- CT thorax bronchial wall thickening, scarring, air space enlargement
- ECG and echocardiogram right atrial and ventricular hypertrophy
- ABG ↓PaO2 +- hypercapnia
- Body mass index (BMI) as a baseline to later assess weight loss (e.g. cancer or severe COPD) or weight gain (e.g. steroids).
- Sputum culture to assess for chronic infections such as pseudomonas.
- Transfer factor for carbon monoxide (TLCO) is decreased in COPD. It can give an indication about the severity of the disease and may be increased in other conditions such as asthma.
Management of COPD
Non-pharmacological:
- Smoking cessation is the single most effective intervention
- Patients should receive a single pneumococcal vaccine and the annual flu vaccine
- Physiotherapy (and by extension, pulmonary rehabilitation)
Pharmacological:
- Short acting beta-2 agonist (SABAs) or short acting muscarinic antagonists (SAMAs) as first line treatment
- Use FEV1 levels to guide further treatment
- If FEV1 >50% offer LABA (eg salmeterol) or LAMA (eg tiotropium) adn discontinue SAMA
- If FEV1 <50% offer LABA + ICS combination therapy or LAMA
- Additional therapies
- Theophylline and mucolytics may be considered
Additional treatment of COPD in severe cases
- Long term oxygen therapy (LTOT)
- Surgical therapy - lung volume reduction therapy, bullectomy or lung transplant
Complications of COPD
- Acute exacerbation
- Polycythaemia
- Respiratory failure
- Cor pulmonale
- Pneumothrax (ruptured bullae)
- Lung carcinoma
How does an exacerbation of COPD present and what casues it?
An exacerbation of COPD presents as acute worsening of symptoms such as cough, shortness of breath, sputum production and wheeze. It is usually triggered by a viral or bacterial infection.
What can an arterial blood gas tell you about a patient with COPD?
Low pH (acidosis) with a raised pCO2 suggests they are retaining CO2 and their blood has become acidotic. This is a respiratory acidosis.
Raised bicarbonate indicates they chronically retain CO2 and their kidneys have responded by producing more bicarbonate to balance the acidic CO2 and maintain a normal pH.
