JC19 (Medicine) - COPD

Question 1

Define COPD

Answer 1

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)

Question 2

2 pathophysiological components of COPD

Answer 2

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

Question 3

Define chronic bronchitis

Answer 3

Chronic inflammation of airway:
cough and sputum on most days for ≥3mo in 2 consecutive years

Question 4

Risk factors of COPD

Answer 4

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)

Question 5

Explain the pathogenesis of COPD
Case
Process
Resulting abnormalities

Answer 5

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

Question 6

Symptoms of COPD

Answer 6

Chronic bronchitis:

• chronic cough with whitish mucoid sputum for years
• May come with haemoptysis in exacerbations

Emphysema: progressive SOB

Features of complications

Question 7

Signs of COPD

• Inspection
• Palpation
• Percussion
• Auscultation

Answer 7

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

Question 8

Complications of COPD (5)

(Acute, chronic and extra-pulmonary)

Answer 8

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

Question 9

2 classical clinical phenotypes of COPD

Answer 9

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)

Question 10

Clinical assessment of dyspnea severity

Answer 10

Question 11

First-line investigation of COPD + rationale (6)

Answer 11

1. CBC for anaemia and polycythaemia (chronic SOB), eosinophilia for overlap with asthma
2. Lung fx tests: Spirometry: post-bronchodilator FEV1/FVC <70% → diagnostic
3. CXR for lung hyperinflation
4. High resolution CT for emphysema and bullae
5. Arterial blood gas: T2RF (if decompensated with chronic hypercapnea), T1RF (if well-compensated)
6. Sputum C/ST for secondary infection

Question 12

Typical CXR features of COPD

Answer 12

Hyperinflation:

• Elongated heart
• Flattened diaphragm
• Hyperlucency of lung fields

Bullae
Cor pulmonale: cardiomegaly, prominent pulmonary trunk

Question 13

Ddx of COPD

Answer 13

1. Chronic asthma - distinguished by bronchodilator reversibility
2. Bronchiectasis - Diagnosed by CXR/HRCT demonstrating airway dilatation
3. Central airway obstruction - Spirometry also shows obstructive pattern but flow volume loop is characteristic for upper airway obstruction (expiratory plateau)
4. Left heart failure - presence of fine basilar crackles and cardiomegaly/pulmonary oedema on CXR

Question 14

Staging of COPD (airflow limitation, symptom severity and risk of exacerbation)

Answer 14

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

Question 15

First line management of Stable COPD

Answer 15

1. Remove risk factors - Stop smoking
2. Bronchodilator: inhaled anticholinergics, β2-agonist
   Anti-inflammatory: ICS, roflumilast
3. Long term oxygen therapy (LTOT)
4. Pulmonary rehabilitation + flu vaccination

Question 16

Management of acute exacerbations of COPD (4)

Answer 16

1. Control oxygen therapy
2. Antibiotics if dyspnea and purulent sputum: Amoxycillin, augmentin, macrolide, cephalosporin
3. Inhaled Bronchodilators (inhaled SABA + SAMA)
4. Inhaled corticosteroids
5. NIV or mechanical ventilation

Question 17

Outline the GOLD ABCD groups of COPD patients

Answer 17

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

Question 18

Treatment of GOLD A COPD

Answer 18

Initial: any bronchodilator (short- or long-acting, based on symptomatic relief)

Subsequent: continue if good symptomatic relief

Question 19

Treatment of GOLD B COPD

Answer 19

Initial: LABA or LAMA

Subsequent: LABA + LAMA → step down if no effect

Question 20

Treatment of GOLD C COPD

Answer 20

Initial: LAMA monotherapy (superior to LABA)
Subsequent: LABA/LAMA or LABA/ICS (a/w ↑pneumonia)

Question 21

Treatment of GOLD D COPD

Answer 21

Initial: LABA/LAMA (superior to LABA/ICS)

Subsequent: triple therapy or switch to LABA/ICS

Further: add roflumilast, macrolide or stop ICS

Question 22

List examples of bronchodilators for COPD

Answer 22

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)

Question 23

Example of ICS for COPD

Indication

One risk

Answer 23

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

Question 24

Management of COPD refractory to Bronchodilator and ICS

Answer 24

Roflumilast: newer oral non-steroid anti-inflammatory agent

Macrolide: azithromycin taken daily to reduce exacerbation

Stopping ICS: Lower risk of pneumonia

Question 25

Indication for LTOT for COPD

Answer 25

Aim: maintain PaO2 ≥8kPa (60mmHg) or SaO2 ≥90% ## Footnote 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

Question 26

Non-pharmalogical management of GOLD B-D COPD

Answer 26

Pulmonary rehabilitation for group B-D: 1. Physiotherapy, muscle and exercise training 2. Nutritional support for cachexia 3. Psychotherapy and education 4. Ventilatory assistance and home care Smoking cessation: find reason of smoking, reason for cessation, manage withdrawal symptoms Medications: (efficacy: V\>B\>N) 1. Nicotine (gum, patch, inhaler) (still w/ S/E of nicotine) 2. Bupropion (Zyban): NE-DA reuptake inhibitor and nicotinic antagonist 3. Varenicline (Champix): nicotinic receptor partial agonist

Question 27

Management of severe COPD (hospitalization)

Answer 27

1. Controlled oxygen therapy 2. Exclude and treat pneumothorax 3. SYSTEMIC corticosteroid (only difference with outpatient frequent exacerbation) 4. Inhaled Bronchodilation 5. Antibiotics coverage 6. NIV

Question 28

Management of cor pulmonale secondary to COPD

Answer 28

Diuretics Salt and fluid restriction

Question 29

Controlled Oxygen therapy for COPD * Target PaO2 * Modes of delivery * Monitoring methods

Answer 29

Aim: PaO2 of 8kPa, SaO2 \>90% Modes: Nasal cannula, venturi mask Monitor: * Clinical (BP, Pulse, Conscious level) * Pulse oximetry * Arterial blood gas measurement

Question 30

Indication for use of antibiotics for COPD

Answer 30

Give if any 2 of: (1) ↑dyspnoea (2) ↑sputum volume (3) purulent sputum Choice of Abx: Amoxycillin, augmentin, macrolide, cephalosporin

Question 31

Long-term management of COPD/ end-stage COPD

Answer 31

1. LTOT 2. Pulmonary Rehabilitation program 3. Yearly Flu vaccination 4. Lung volume reduction surgery 5. Lung transplantation

Question 32

Reasons for chronic smoking

Answer 32

overlearnt habit, routine, craving, stress, social-peer pressure, relaxation, addiction to Nicotine

Question 33

Reasons for smoking cessation

Answer 33

save money, more socially acceptable, not harm other, improve health, clothes and home smell fresher, ↑appreciation of taste and smell, fire hazard

Question 34

Withdrawal symptoms from smoking

Answer 34

craving, coughing, hunger/weight gain, bowel disturbance, sleep disturbance, dizziness, paraesthesia, mood swings, lack of concentration and irritability

Question 35

Medication for quitting smoking

Answer 35

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

Question 36

Comorbidities of stable COPD