JC19 (Medicine) - COPD Flashcards
Define COPD
Chronic obstructive pulmonary disease (COPD): disease characterized by
□ Progressive but not fully reversible airflow obstruction (unlike chronic asthma)
□ Due to inflammatory response to toxic particles or gases (especially smoking)
2 pathophysiological components of COPD
Components of COPD arise as consequence of inflammation in different parts of the lung
Airways → chronic bronchitis
Alveoli → emphysema: abnormal permanent enlargement of airspaces distal to terminal bronchioles accompanied with destruction of their walls + fibrosis
Define chronic bronchitis
Chronic inflammation of airway:
cough and sputum on most days for ≥3mo in 2 consecutive years
Risk factors of COPD
Environmental:
→ Cigarette smoking (>85%) and passive smoking
→ Air pollution
→ Indoor biomass combustion
→ Occupational exposure
Host: α1-antitrypsin deficiency (rare, only consider if young <45y+ Caucasian)
Explain the pathogenesis of COPD
Case
Process
Resulting abnormalities
Cause: inhalation of noxious materials
Processes:
1) Chronic inflammation → mucus hypersecretion, inflammatory infiltrates → airway obstruction + collapse of distal poorly supported airways
- *2) Progressive destruction of lung tissues**
- Small airways peribronchiolar fibrosis, airway narrowing
- Alveoli emphysema → ↓radial traction → airway obstruction
Results:
Small airway obstruction → air trapping → hyperinflated lungs
Respiratory failure due to V/Q mismatch: destruction of alveolar capillary bed + non-uniform airflow obstruction
Severe hypoxaemia + hypercapnia → blunted central resp drive
Alveolar hypoventilation due to airway resistance + hyperinflation → ↑work of breathing
Symptoms of COPD
Chronic bronchitis:
- chronic cough with whitish mucoid sputum for years
- May come with haemoptysis in exacerbations
Emphysema: progressive SOB
Features of complications
Signs of COPD
- Inspection
- Palpation
- Percussion
- Auscultation
General: tar staining, NO clubbing
- Inspection:
Pursed lip breathing
Barrel chest with ↓distance between suprasternal notch and cricoid cartilage
Respiratory distress ± central cyanosis
Intercostal indrawing during inspiration - Palpation:
Decrease chest expansion bilaterally
Hoover’s sign: inward movement of lower ribs on inspiration - Percussion: loss of cardiac and hepatic dullness
- Auscultation:
Coarse inspiratory crackles in episodes of infection
Prolonged expiratory phase ± wheezing
Decrease breath and heart sounds
Complications of COPD (5)
(Acute, chronic and extra-pulmonary)
Acute exacerbations:
- Pneumothorax (↓air entry, hyperresonance)
- Critical airflow obstruction (↑wheezing)
- Infection (signs of consolidation)
- Acute respiratory failure
Chronic complications:
- Chronic respiratory failure
- Lung Cancer
Extra-pulmonary:
- Cor pulmonale: chronic hypoxaemia → pulmonary hypertension → RV failure
- Heart disease: IHD, HF, Arrhythmia, CAD
2 classical clinical phenotypes of COPD
Two classical clinical phenotypes:
(2) Blue bloaters (type B): predominant chronic bronchitis with cyanosis and fluid retention (tachypnoeic compensation ineffective resulting in cyanosis and cor pulmonale)
Note that these phenotypes often overlap
(1) Pink puffers (type A): predominant emphysema with tachypnoea and little cyanosis (tachypnoeic compensation effective)
Clinical assessment of dyspnea severity
First-line investigation of COPD + rationale (6)
- CBC for anaemia and polycythaemia (chronic SOB), eosinophilia for overlap with asthma
- Lung fx tests: Spirometry: post-bronchodilator FEV1/FVC <70% → diagnostic
- CXR for lung hyperinflation
- High resolution CT for emphysema and bullae
- Arterial blood gas: T2RF (if decompensated with chronic hypercapnea), T1RF (if well-compensated)
- Sputum C/ST for secondary infection
Typical CXR features of COPD
Hyperinflation:
- Elongated heart
- Flattened diaphragm
- Hyperlucency of lung fields
Bullae
Cor pulmonale: cardiomegaly, prominent pulmonary trunk
Ddx of COPD
- Chronic asthma - distinguished by bronchodilator reversibility
- Bronchiectasis - Diagnosed by CXR/HRCT demonstrating airway dilatation
- Central airway obstruction - Spirometry also shows obstructive pattern but flow volume loop is characteristic for upper airway obstruction (expiratory plateau)
- Left heart failure - presence of fine basilar crackles and cardiomegaly/pulmonary oedema on CXR
Staging of COPD (airflow limitation, symptom severity and risk of exacerbation)
Assessment of airflow limitation by % predicted FEV1 (spirometric grade, in numbers)
→ Grading: ≥80% (GOLD1), 50-79% (GOLD2), 30-49 (GOLD3), <30 (GOLD4)
Assessment of symptoms and risk of exacerbations: (ABCD groups, in letters)
→ Symptoms by modified MRC scale (mMRC) or COPD assessment tool (CAT)
→ Risk of exacerbation by frequency of episodes
First line management of Stable COPD
- Remove risk factors - Stop smoking
- Bronchodilator: inhaled anticholinergics, β2-agonist
Anti-inflammatory: ICS, roflumilast - Long term oxygen therapy (LTOT)
- Pulmonary rehabilitation + flu vaccination
Management of acute exacerbations of COPD (4)
- Control oxygen therapy
- Antibiotics if dyspnea and purulent sputum: Amoxycillin, augmentin, macrolide, cephalosporin
- Inhaled Bronchodilators (inhaled SABA + SAMA)
- Inhaled corticosteroids
- NIV or mechanical ventilation
Outline the GOLD ABCD groups of COPD patients
Class D = >2 exacerbation + lots of symptoms
Class A = no exacerbation + little symptom
A = 0/1 outpatient exacerbation + 0/1 MRC dyspnea scale
B = 0/1 outpatient exacerbation + 2+ MRC dyspnea scale
C = 2+ outpatient exacerbation or 1+ inpatient episode + 0/1 MRC dyspnea scale
D = 2+ outpatient exacerbation or 1+ inpatient episode + 2+ MRC dyspnea scale
Treatment of GOLD A COPD
Initial: any bronchodilator (short- or long-acting, based on symptomatic relief)
Subsequent: continue if good symptomatic relief
Treatment of GOLD B COPD
Initial: LABA or LAMA
Subsequent: LABA + LAMA → step down if no effect
Treatment of GOLD C COPD
Initial: LAMA monotherapy (superior to LABA)
Subsequent: LABA/LAMA or LABA/ICS (a/w ↑pneumonia)
Treatment of GOLD D COPD
Initial: LABA/LAMA (superior to LABA/ICS)
Subsequent: triple therapy or switch to LABA/ICS
Further: add roflumilast, macrolide or stop ICS
List examples of bronchodilators for COPD
Short-acting agents: as needed for symptomatic relief in group A only
→ SABA: terbutaline (Bricanyl), salbutamol (Ventolin)
→ SAMA: ipratropium (Atrovent)
Long-acting agents: for regular use for symptomatic relief and prevent exacerbation
→ LABA: salmeterol (Serevent), formoterol (Oxis), indacaterol (ultra-long acting, not used in asthma)
→ LAMA: tiotropium (Spiriva)
Example of ICS for COPD
Indication
One risk
Inhaled corticosteroids (ICS), eg. beclomethasone (becloforte), budesonide (pulmicort), fluticasone (flixotide)
Use: as combination with bronchodilator therapy in those with frequent exacerbations
High risk of pneumonia → STOPPED if exacerbation while on triple therapy
Management of COPD refractory to Bronchodilator and ICS
Roflumilast: newer oral non-steroid anti-inflammatory agent
Macrolide: azithromycin taken daily to reduce exacerbation
Stopping ICS: Lower risk of pneumonia
Indication for LTOT for COPD
Aim: maintain PaO2 ≥8kPa (60mmHg) or SaO2 ≥90%
Continuous LTO2
→ Resting PaO2 <7.3kPa (55mmHg) or SaO2 ≤88%
Non-continuous LTO2 when
→ During exercise, PaO2 <7.3kPa (55mmHg) or SaO2 ≤88%
→ During sleep, PaO2 <7.3kPa (55mmHg) or SaO2 ≤88% with associated complications
Non-pharmalogical management of GOLD B-D COPD
Pulmonary rehabilitation for group B-D:
- Physiotherapy, muscle and exercise training
- Nutritional support for cachexia
- Psychotherapy and education
- Ventilatory assistance and home care
Smoking cessation: find reason of smoking, reason for cessation, manage withdrawal symptoms
Medications: (efficacy: V>B>N)
- Nicotine (gum, patch, inhaler) (still w/ S/E of nicotine)
- Bupropion (Zyban): NE-DA reuptake inhibitor and nicotinic antagonist
- Varenicline (Champix): nicotinic receptor partial agonist
Management of severe COPD (hospitalization)
- Controlled oxygen therapy
- Exclude and treat pneumothorax
- SYSTEMIC corticosteroid (only difference with outpatient frequent exacerbation)
- Inhaled Bronchodilation
- Antibiotics coverage
- NIV
Management of cor pulmonale secondary to COPD
Diuretics
Salt and fluid restriction
Controlled Oxygen therapy for COPD
- Target PaO2
- Modes of delivery
- Monitoring methods
Aim: PaO2 of 8kPa, SaO2 >90%
Modes: Nasal cannula, venturi mask
Monitor:
- Clinical (BP, Pulse, Conscious level)
- Pulse oximetry
- Arterial blood gas measurement
Indication for use of antibiotics for COPD
Give if any 2 of:
(1) ↑dyspnoea (2) ↑sputum volume (3) purulent sputum
Choice of Abx: Amoxycillin, augmentin, macrolide, cephalosporin
Long-term management of COPD/ end-stage COPD
- LTOT
- Pulmonary Rehabilitation program
- Yearly Flu vaccination
- Lung volume reduction surgery
- Lung transplantation
Reasons for chronic smoking
overlearnt habit,
routine,
craving,
stress, social-peer pressure,
relaxation,
addiction to Nicotine
Reasons for smoking cessation
save money,
more socially acceptable,
not harm other,
improve health,
clothes and home smell fresher,
↑appreciation of taste and smell,
fire hazard
Withdrawal symptoms from smoking
craving,
coughing,
hunger/weight gain,
bowel disturbance,
sleep disturbance,
dizziness, paraesthesia,
mood swings,
lack of concentration and irritability
Medication for quitting smoking
Nicotine (gum, patch, inhaler) (still w/ S/E of nicotine)
Bupropion (Zyban): NE-DA reuptake inhibitor and nicotinic antagonist
Varenicline (Champix): nicotinic receptor partial agonist: ↓withdrawal symptoms, ↓reinforcing effect if start smoking again
Comorbidities of stable COPD
