Chronic Obstructive Pulmonary Disease (COPD)

1. Definition

Chronic Obstructive Pulmonary Disease (COPD) is a common, preventable, and treatable chronic respiratory disease characterized by:

Persistent respiratory symptoms (dyspnea, cough, sputum production)
Chronic airflow limitation due to airway inflammation, remodeling, and alveolar destruction
Airflow limitation is not fully reversible and is confirmed by spirometry:
- Post-bronchodilator FEV₁/FVC < 0.70

2. Causes

Category	Examples
Environmental	Tobacco smoke (most common), biomass fuel, air pollution
Occupational	Dusts, chemicals, vapors
Infective	Recurrent childhood lower respiratory tract infections
Genetic	Alpha-1 antitrypsin deficiency
Others	Asthma-COPD overlap, bronchiectasis

3. Risk Factors

Smoking (active or passive)
Indoor air pollution (e.g., cooking with biomass)
Occupational exposure to dust and chemicals
Age > 40 years
Male sex
Recurrent childhood lower respiratory infections
Genetic predisposition (e.g., α1-antitrypsin deficiency)
Low socioeconomic status
Family history of COPD

4. Types and Classifications

GOLD 2024 Spirometric Grades

GOLD Grade	FEV₁ (% predicted, post-bronchodilator)
GOLD 1	≥80%
GOLD 2	50–79%
GOLD 3	30–49%
GOLD 4	<30%

GOLD 2024 ABE Grouping

Group	Symptoms (CAT ≥10 or mMRC ≥2)	Exacerbation History
A	Low	0–1 moderate exacerbation, no hospitalization
B	High	0–1 moderate exacerbation, no hospitalization
E	Any	≥2 moderate or ≥1 leading to hospitalization

5. Pathogenesis

Chronic exposure to irritants (e.g., smoke) causes airway inflammation and recruitment of neutrophils, macrophages, and CD8+ T cells
Leads to:
- Airway narrowing and fibrosis
- Mucus hypersecretion (chronic bronchitis)
- Alveolar wall destruction (emphysema)
Consequences:
- Airflow obstruction
- Air trapping and hyperinflation
- Ventilation-perfusion (V/Q) mismatch
- Impaired gas exchange and respiratory failure

6. Clinical Features

Symptoms

Chronic:

Progressive exertional dyspnea
Chronic productive cough
Intermittent wheeze
Reduced exercise tolerance
Fatigue

Acute (Exacerbation):

Increased dyspnea
Increased sputum volume and/or purulence
Wheezing, chest tightness
Fever (if infective cause)

Scale/Scoring

mMRC Dyspnea Scale
CAT (COPD Assessment Test)

Physical Examination

General Examination

Component	Findings
GCS	Normal; reduced if CO₂ retention encephalopathy
Bedside	Pursed-lip breathing, barrel chest, cachexia
Vital signs	Tachypnea, tachycardia, hypoxia, low-grade fever
Hands	Cyanosis, tremor (CO₂ retention), nicotine stains
Face	Central cyanosis, sunken cheeks in advanced disease

System-Based Examination

Respiratory:

Hyperresonant chest percussion
Decreased breath sounds
Prolonged expiratory phase
Diffuse wheeze or crackles
Hoover’s sign (inward rib movement during inspiration)

Cardiovascular:

Elevated JVP (if cor pulmonale)
Loud pulmonary component of S2 (P2)
Peripheral edema

7. Organ & System Complications

System	Complication
Respiratory	Respiratory failure, pneumothorax, pneumonia, bullae
Cardiovascular	Pulmonary hypertension, cor pulmonale, arrhythmias
Musculoskeletal	Muscle wasting, osteoporosis (due to steroids), sarcopenia
Neurological	CO₂ retention encephalopathy
Hematologic	Secondary polycythemia
Psychological	Depression, anxiety
Metabolic	Weight loss, cachexia

8. Diagnostic Investigations (with expected results)

Investigation	Expected Result
Spirometry	Post-BD FEV₁/FVC < 0.70; FEV₁ ↓ based on GOLD
Chest X-ray	Hyperinflated lungs, flattened diaphragms, increased retrosternal airspace (lateral view), decreased peripheral vascular markings, vertical/narrow heart ("saber-sheath" heart), barrel-shaped chest (increased AP diameter), and possible bullae or areas of radiolucency (especially in emphysema)
ABG (if needed)	↓PaO₂ ± ↑PaCO₂ in advanced disease
CBC	Possible secondary polycythemia (chronic hypoxia)
Pulse oximetry	SpO₂ < 92% in moderate-to-severe cases

9. Other Relevant Investigations (with expected results)

Investigation	Purpose / Expected Result
Alpha-1 antitrypsin level	Low in early-onset or non-smoker COPD
6-minute walk test	Reduced distance, desaturation during exertion
Sputum culture	Identify pathogens in exacerbations
ECG / Echocardiography	RV strain, cor pulmonale, pulmonary hypertension
HRCT (if indicated)	Confirm emphysema, rule out bronchiectasis
BNP / NT-proBNP	Elevated if heart failure coexists
COVID-19 / Influenza PCR	If acute respiratory symptoms present

10. Treatment

Stepwise Acute (Exacerbation) Management

Assess severity of exacerbation (dyspnea, RR, SpO₂, mental state)
Administer oxygen to maintain SpO₂ 88–92%
Administer short-acting bronchodilators (SABA ± SAMA via nebulizer or MDI with spacer)
Start systemic corticosteroids (e.g., prednisolone 30–40 mg/day for 5–7 days)
Add empirical antibiotics if ≥2 of the following:
- Increased dyspnea
- Increased sputum volume
- Purulent sputum
Consider non-invasive ventilation (NIV) if:
- pH <7.35 and PaCO₂ >6.0 kPa
Monitor ABG, vitals, and response
Escalate care if patient fails to improve or deteriorates

Long-Term Management

Curative/Definitive

No cure; surgery considered in advanced cases:
- Lung volume reduction surgery
- Lung transplantation (select patients)

Empirical

Inhaled maintenance therapy:
- GOLD A: SABA or LABA or LAMA
- GOLD B: LABA + LAMA
- GOLD E: LABA + LAMA ± ICS (if eos ≥300 cells/μL or asthma overlap)
Roflumilast for frequent exacerbators with chronic bronchitis

Supportive

Smoking cessation (most effective intervention)
Pulmonary rehabilitation
Annual influenza and pneumococcal vaccination
Oxygen therapy if PaO₂ ≤ 55 mmHg (or ≤ 60 mmHg with RHF/polycythemia)
Nutritional support and exercise

Palliative

Low-dose opioids for refractory dyspnea
Benzodiazepines for anxiety
Advance care planning

11. Long-Term Effects / Complications of Treatment

Treatment	Complication	Monitoring	Expected Result
Inhaled corticosteroids	Pneumonia, oral candidiasis	Sputum cultures, oral exam	Symptom resolution, no infection
Systemic steroids	Osteoporosis, hyperglycemia	DEXA, blood glucose	T-score > –2.5, HbA1c < 7.0%
Oxygen therapy	CO₂ retention, oxygen toxicity	ABG, SpO₂	PaO₂ > 60 mmHg, PaCO₂ stable
Long-acting bronchodilators	Tachycardia, tremor	HR, BP monitoring	Stable vitals

12. Surveillance for the Disease

Measure	Frequency	Setting
Spirometry	Annually	Clinic
CAT / mMRC score	Each follow-up	Clinic/Telehealth
Smoking status	Every visit	Clinic
Oxygen requirement (ABG)	6–12 monthly	Hospital/Clinic
Exacerbation frequency	Every review	Clinic
Vaccination status	Yearly review	Clinic

13. References

Malaysia Clinical Practice Guidelines
- Management of Chronic Obstructive Pulmonary Disease, 2nd Edition, 2023
- Ministry of Health Malaysia
- https://www.moh.gov.my
UK NICE Guidelines
- NICE NG115: Chronic obstructive pulmonary disease in over 16s: diagnosis and management (2023 review)
- https://www.nice.org.uk/guidance/ng115
GOLD 2024 Global Strategy
- Global Initiative for Chronic Obstructive Lung Disease (GOLD)
- https://goldcopd.org/2024-gold-report-2/
UpToDate
- “Chronic obstructive pulmonary disease: diagnosis and management”
- “Management of acute exacerbation of COPD”