Key Facts

COPD is a common, preventable, and treatable disease characterised by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities, usually caused by significant exposure to noxious particles or gases, most commonly tobacco smoke.

Epidemiology

• 1.2 million diagnosed, estimated 3 million total (including undiagnosed) in the UK
• Third leading cause of death worldwide (WHO)
• Approximately 30,000 deaths/year in the UK
• Prevalence: 2% overall; >10% in smokers >40 years
• Significant health inequality: 3-5× more prevalent in most deprived quintile

Aetiology

• Smoking: >85% of cases; risk proportional to pack-years
• Alpha-1 antitrypsin deficiency: 1-2% of cases; suspect if young onset, non-smoker, lower lobe emphysema
• Occupational exposure: coal dust, silica, cadmium, grain dust
• Air pollution: indoor (biomass fuel) and outdoor
• Childhood lung infections: severe childhood pneumonia

Pathophysiology

• Chronic bronchitis: mucus hypersecretion, goblet cell metaplasia, squamous metaplasia of bronchial epithelium
• Emphysema: destruction of alveolar walls distal to terminal bronchioles; loss of elastic recoil; air trapping
• Small airway disease: inflammation and fibrosis of small airways (<2mm)
• Neutrophilic inflammation (unlike asthma's eosinophilic predominance)
• Progressive, largely irreversible airflow limitation
• Systemic effects: skeletal muscle wasting, cardiovascular disease, osteoporosis, depression, lung cancer risk

Typical Presentation

• Exertional dyspnoea (progressive over years)
• Chronic productive cough (particularly morning)
• Wheeze
• History of smoking (typically >10 pack-years)
• Age typically >35 years
• Reduced exercise tolerance

Examination

• Hyperinflation (barrel chest, reduced cricosternal distance)
• Pursed lip breathing
• Use of accessory muscles
• Wheeze and reduced air entry on auscultation
• Cyanosis (if hypoxic)
• Peripheral oedema (cor pulmonale)

Red Flags

• Rapidly progressive dyspnoea (exclude PE, pneumothorax, heart failure)
• Haemoptysis (exclude lung cancer)
• Significant weight loss (exclude lung cancer, TB)
• Young onset without smoking history (alpha-1 antitrypsin deficiency)
• Cor pulmonale (peripheral oedema, raised JVP)

Diagnostic

• Post-bronchodilator spirometry: FEV1/FVC <0.7 confirms airflow obstruction
  • Mild: FEV1 ≥80% predicted
  • Moderate: FEV1 50-79%
  • Severe: FEV1 30-49%
  • Very severe: FEV1 <30%
• Reversibility testing: limited reversibility (<12% or <200ml) — distinguishes from asthma

Baseline

• CXR: hyperinflation, flat diaphragms, bullae; exclude other pathology
• FBC: polycythaemia (chronic hypoxia), anaemia
• BMI: track nutritional status
• Pulse oximetry: SpO2 <92% → refer for ABG and LTOT assessment
• Alpha-1 antitrypsin level: in all patients (one-time test)

Monitoring

• Spirometry annually
• MRC dyspnoea scale (grade 1-5)
• Exacerbation frequency
• BMI
• CAT score (COPD Assessment Test)

Special Tests

• ABG: for LTOT assessment (PaO2 ≤7.3kPa)
• TLCO (transfer factor): reduced in emphysema
• HRCT: if bronchiectasis or alternative diagnosis suspected
• Echocardiography: if cor pulmonale or concurrent heart failure suspected

Non-pharmacological

• Smoking cessation: single most important intervention; offer NRT, varenicline (1mg BD for 12 weeks), or cytisine
• Pulmonary rehabilitation: 6-12 week supervised exercise + education programme; offer to all MRC grade ≥3; NNT 4 to prevent hospitalisation
• Annual influenza vaccination + pneumococcal vaccination
• Self-management plan: recognising and managing exacerbations
• Nutritional support (if BMI <20)
• Psychological support (anxiety, depression common)

Pharmacological — NICE NG115 Inhaler Pathway

• Initial: SABA (salbutamol) or SAMA (ipratropium) PRN
• If persistent symptoms/exacerbations:
  • No asthmatic features/lower eosinophils: LABA (formoterol/salmeterol) + LAMA (tiotropium/glycopyrronium) — e.g. Ultibro Breezhaler
  • Asthmatic features/higher eosinophils (≥300): LABA + ICS — e.g. Symbicort, Seretide
• If still uncontrolled: Triple therapy — LABA + LAMA + ICS (e.g. Trimbow, Trelegy Ellipta)
• Mucolytics: carbocisteine 750mg TDS if chronic productive cough
• Oral theophylline: consider after inhaler optimisation (narrow therapeutic index — monitor levels)
• Prophylactic antibiotics: azithromycin 250mg 3×/week for patients with ≥3 exacerbations/year (specialist initiation; check ECG/QTc, LFTs, sputum culture for NTM)

Long-Term Oxygen Therapy (LTOT)

• Indications: PaO2 ≤7.3kPa on two ABGs 3 weeks apart (stable), or PaO2 ≤8kPa with secondary polycythaemia, pulmonary hypertension, or peripheral oedema
• Use for ≥15 hours/day (MRC LTOT trial: improved survival)
• Target SpO2 88-92% in exacerbation
• NEVER prescribe LTOT without confirming smoking cessation (fire/explosion risk)

Acute Exacerbation Management

• Controlled oxygen: 24-28% Venturi mask, target SpO2 88-92%
• Nebulised bronchodilators: salbutamol 2.5-5mg + ipratropium 500mcg
• Prednisolone 30mg OD for 5 days (no need to taper)
• Antibiotics: if purulent sputum — amoxicillin 500mg TDS 5 days, doxycycline 200mg stat then 100mg OD, or clarithromycin 500mg BD
• NIV (BiPAP): for acute hypercapnic respiratory failure (pH 7.25-7.35) despite initial treatment

Referral Criteria

• Respiratory specialist: diagnostic uncertainty, FEV1 <30%, frequent exacerbations (≥3/year), LTOT assessment, alpha-1 antitrypsin deficiency, lung volume reduction surgery consideration
• Palliative care: severe COPD with significant symptom burden

• COPD is a progressive disease; FEV1 decline can be slowed by smoking cessation but not reversed
• Smoking cessation: reduces rate of FEV1 decline from 60ml/year to ~30ml/year (Lung Health Study)
• BODE index (BMI, Obstruction, Dyspnoea, Exercise capacity) predicts mortality
• Median survival with FEV1 <30%: approximately 3-4 years
• Acute exacerbation requiring hospitalisation: 10% in-hospital mortality, 25% 1-year mortality
• LTOT improves survival in hypoxic patients (MRC LTOT trial: reduced mortality by ~50% at 5 years)
• Pulmonary rehabilitation improves exercise capacity and quality of life but does not alter FEV1
• Lung cancer risk is significantly increased in COPD (independent of smoking)

MRC Dyspnoea Scale

NICE NG115 Inhaler Selection Summary

GOLD ABCD Assessment Tool