Chronic Obstructive Pulmonary Disease Flashcards
Definition
Chronic, progressive lung disorder characterised by airflow obstruction, with the following:
Chronic bronchitis
(chronic cough and sputum production on most days for at least 3 months per year over 2 consecutive years)
Emphysema
(pathological diagnosis of permanent destructive enlargement of air spaces distal to teh terminal bronchioles)
Risk factors
Bronchial and alveolar damage is caused by environmental toxins (eg cigarette smoke)
RARE cause: alpha1 antitrypsin deficiency
(rare but consider in young patients who have never smoked and present with COPD type symptoms, maybe with additional symptoms of cirrhosis)
Aetiology (chronic bronchitis)
Narrowing of the airways resulting in bronchiole inflammation
Bronchial mucosal oedema
Mucous hypersecretion
Squamous metaplasia
Aetiology (emphysema)
Destruction and enlargement of alveoli
Leads to loss of elasticity that keeps small airways open in expiration
Progressively larger spaces develop called bullae (> 1cm in diameter)
Epidemiology
VERY COMMON (8% prevalence)
Presents in middle age or later
More common in males - may change due to increase in female smokers
Presenting symptoms
Chronic cough Sputum production Breathlessness Wheeze Reduced exercise tolerance
Signs on physical examination (inspection)
Respiratory distress Use of accessory muscles Barrel-shaped over-inflated chest Decreased cricosternal distance Cyanosis
Signs on physical examination (percussion)
Hyper-resonant chest
Loss of liver and cardiac dullness
Signs on physical examination (auscultation)
Quiet breath sounds Prolonged expiration Wheeze Rhonchi (rattling, continuous and low-pitched breath sounds that sound like snoring (often caused by secretions or obstructions) Sometimes crepitations
Signs on physical examination (signs of CO2 retention)
Bounding pulse
Warm peripheries
Asterixis
Late stages: Signs of right heart failure (cor pulmonale) Right ventricular heave Raised JVP Ankle oedema
Investigations
Spirometry and pulmonary function tests:
- Reduced PEFR
- Reduced FEV1/FVC
- Increased lung volumes
- Decreased carbon monoxide gas transfer coefficient
(these features shows an obstructive picture)
CXR:
- May appear normal
- Hyperinflation
- Reduced peripheral lung markings
- Elongated cardiac silhouette
Bloods:
- FBC
- Increased Hb and haematocrit due to secondary polycythaemia
ABG:
- may show hypoxia, normal/raised PCO2
ECG and echocardiogram:
- check for cor pulmonale
Sputum and blood cultures:
- useful in acute infective exacerbations
Alpha1 antitrypsin levels:
- Useful in young patients who have never smoked
Management plan (long term)
STOP SMOKING
Bronchodilators:
- short acting b2 agonist (salbutamol)
- anticholinergics (ipratropium bromide)
- long acting b2 agonist (if > 2 exacerbations a year
Steroids:
- inhaled beclomethasone (if FEV1 < 50% of predicted OR >2 exacerbations per year)
- regular oral steroids should be avoided if possible
Pulmonary rehabilitation
Oxygen therapy:
- only for those who stop smoking
- indicated if PaO2 < 7.3kPa on air during stable period OR if PaO2 is between 7.3 - 8kPa and signs of secondary polycythaemia, nocturnal hypoxaemia, peripheral oedema or pulmonary hypertension
Management plan (during acute exacerbations)
24% O2 Venturi mask
Increase slowly if no hypercapnia and still hypoxic (do an ABG)
Corticosteroids
Start empirical antibiotic therapy if evidence of infection
Respiratory physiotherapy to clear sputum
Non-invasive ventilation may be necessary in severe cases
Management plan (prevention of infective exacerbations)
Pneumococcal vaccination
Influenza vaccination
Possible complications
Acute respiratory failure Infections Pulmonary hypertension Right heart failure Pneumothorax (secondary to bullae rupture) Secondary polycythaemia
