Quick Overview
Asthma is a chronic inflammatory airway disease characterized by variable airflow obstruction and bronchial hyperresponsiveness. NICE NG80 emphasizes objective diagnosis before treatment initiation to avoid misdiagnosis and inappropriate long-term therapy. Management follows a stepwise approach with clear criteria for escalation and specialist referral.
Core Facts & Concepts
Diagnostic Criteria (NICE NG80)
-
FeNO (Fractional exhaled Nitric Oxide) thresholds:
- Adults: ≥40 ppb = positive (supports asthma diagnosis)
- Children (5-16y): ≥35 ppb = positive
- Intermediate: 25-39 ppb (adults), 20-34 ppb (children)
-
Spirometry with reversibility:
- FEV₁/FVC ratio <70% (airflow obstruction)
- Reversibility: ≥12% AND ≥200ml improvement in FEV₁ post-bronchodilator
- If negative but high clinical suspicion: consider peak flow variability (>20% diurnal variation)
📊 Objective Testing Requirements:
- Never start ICS without objective confirmation (spirometry/FeNO/peak flow variability)
- Steroid responsiveness testing if initial tests inconclusive
| Test | Positive Result | When to Use |
|---|---|---|
| FeNO | ≥40 ppb (adults) | First-line, non-invasive |
| Spirometry + BD | ≥12% + 200ml FEV₁ | Gold standard confirmation |
| Peak flow diary | >20% variability | If spirometry unavailable |
| Challenge test | PC₂₀ ≤8 mg/ml | Specialist setting only |
Problem-Solving Approach
Stepwise Treatment Ladder (NICE NG80):
- Step 1: SABA (salbutamol/terbutaline) as-needed only
- Step 2: Add low-dose ICS (≤400 mcg beclometasone-equivalent daily)
- Step 3: Add LABA (consider MART therapy here - see below)
- Step 4: Increase ICS to moderate dose (400-800 mcg) OR add LTRA (montelukast)
- Step 5: Specialist referral + consider high-dose ICS, biologics, oral steroids
🎯 MART (Maintenance And Reliever Therapy) Positioning:
- From Step 3 onwards: ICS-formoterol combination (e.g., budesonide-formoterol)
- Used as both preventer AND reliever
- Reduces exacerbation risk vs separate ICS+LABA
- ⚠️ NOT suitable for SABA-only patients
🚩 Specialist Referral Criteria:
- Uncontrolled on Step 4 therapy
- ≥2 exacerbations requiring oral steroids in 12 months
- ≥1 severe exacerbation requiring hospital admission
- Diagnostic uncertainty despite objective testing
- Suspected occupational asthma
- Pregnancy with poorly controlled asthma
Analysis Framework
Differential Diagnosis - Distinguishing Features:
| Condition | Key Discriminator | Investigation |
|---|---|---|
| Asthma | Variable symptoms, reversibility | FeNO ↑, spirometry reversible |
| COPD | Fixed obstruction, smoking Hx, age >35 | Post-BD FEV₁/FVC <70% persists |
| Bronchiectasis | Chronic productive cough, infections | CT chest: bronchial dilation |
| Cardiac failure | Orthopnoea, raised JVP, oedema | BNP ↑, echo abnormal |
| VCD | Inspiratory stridor, normal FeNO | Flow-volume loop flattening |
⭐ Clinical Pearl: If using ≥3 SABA inhalers/year = poor control, escalate therapy and review technique.
Visual Aid
Key Points Summary
✓ Never treat without objective diagnosis: FeNO ≥40 ppb OR spirometry reversibility ≥12%+200ml
✓ MART therapy (ICS-formoterol) from Step 3: single inhaler for maintenance + relief
✓ ICS doses: Low ≤400 mcg, Moderate 400-800 mcg (beclometasone-equivalent)
✓ Refer if: Uncontrolled on Step 4, ≥2 oral steroid courses/year, or hospital admission
✓ Red flag: ≥3 SABA inhalers/year indicates poor control - escalate immediately
✓ Peak flow variability >20% supports diagnosis if spirometry unavailable
✓ Avoid misdiagnosis: 30% of "asthma" patients lack objective evidence - always test first
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