COPD diagnosis and exacerbations

Quick Overview

COPD is a progressive obstructive airway disease diagnosed by post-bronchodilator spirometry showing FEV1/FVC <0.7. Management focuses on symptom control, exacerbation prevention, and timely escalation during acute deteriorations. NICE NG115 emphasizes individualized inhaler therapy based on exacerbation frequency and blood eosinophil counts.

Core Facts & Concepts

Diagnostic Criteria (NICE NG115)

• Spirometry: Post-bronchodilator FEV1/FVC <0.7 confirms airflow obstruction
• Perform in stable state (≥6 weeks post-exacerbation)
• FEV1 % predicted determines severity but doesn't guide treatment alone

MRC Dyspnoea Scale (guides treatment escalation)

Severity Classification by FEV1

• Stage 1 (Mild): ≥80% predicted
• Stage 2 (Moderate): 50-79% predicted
• Stage 3 (Severe): 30-49% predicted
• Stage 4 (Very severe): <30% predicted

📊 Key Thresholds

• Eosinophil count ≥300 cells/μL: Consider ICS addition
• ≥2 exacerbations/year: Escalate therapy
• pH <7.35: Consider NIV in type 2 respiratory failure

Problem-Solving Approach

Acute Exacerbation Management (Stepwise)

1. Assess severity: Respiratory rate, oxygen saturations, ability to speak, consciousness level
2. Oxygen therapy: Target SpO2 88-92% (controlled oxygen to avoid CO2 retention)
3. Bronchodilators: Nebulized salbutamol 5mg + ipratropium 500mcg QDS
4. Corticosteroids: Prednisolone 30mg daily for 5 days (all exacerbations requiring hospital treatment)
5. Antibiotics if ≥2 of: ↑dyspnoea, ↑sputum volume, purulent sputum (Anthonisen criteria)
   • First-line: amoxicillin 500mg TDS or doxycycline 200mg loading then 100mg daily (5 days)

🚩 NIV Criteria (pH-driven)

• pH 7.25-7.35 with pCO2 >6.5 kPa despite optimal medical therapy
• pH <7.25: Consider ICU/intubation
• Contraindications: Impaired consciousness, facial trauma, vomiting

Inhaler Escalation Algorithm (NICE NG115)

• No asthmatic features: LABA+LAMA dual therapy
• Asthmatic features + eosinophils ≥300: LABA+LAMA+ICS triple therapy
• Frequent exacerbations (≥2/year) on LABA+LAMA: Add ICS if eosinophils ≥100

Analysis Framework

Differentiating Exacerbation Triggers

Asthmatic Features Suggesting ICS Benefit

• Previous asthma/atopy diagnosis
• Diurnal/day-to-day variability
• Eosinophils ≥300 cells/μL
• FeNO ≥40 ppb (if available)

Visual Aid

Anthonisen Criteria for Antibiotics

1. Increased dyspnoea
2. Increased sputum volume
3. Purulent sputum (most specific)

Key Points Summary

✓ Diagnosis: Post-bronchodilator FEV1/FVC <0.7 on spirometry (perform when stable)

✓ Exacerbation antibiotics: Only if ≥2 Anthonisen criteria (↑dyspnoea, ↑sputum volume, purulent sputum)

✓ Oxygen target: 88-92% SpO2 to prevent hypercapnia in acute setting

✓ NIV threshold: pH 7.25-7.35 with pCO2 >6.5 kPa despite maximal medical therapy

✓ Inhaler escalation: LABA+LAMA baseline; add ICS if eosinophils ≥300 cells/μL or ≥100 with frequent exacerbations

✓ Steroids: Prednisolone 30mg for 5 days in all hospitalized exacerbations

✓ MRC grade ≥3: Significant functional impairment-consider pulmonary rehabilitation referral