Asthma diagnosis and long-term management

Asthma diagnosis and long-term management

Asthma diagnosis and long-term management

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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)

Figure 1: Spirometry graph showing obstructive pattern with post-bronchodilator improvement in FEV1

📊 Objective Testing Requirements:

  • Never start ICS without objective confirmation (spirometry/FeNO/peak flow variability)
  • Steroid responsiveness testing if initial tests inconclusive
TestPositive ResultWhen to Use
FeNO≥40 ppb (adults)First-line, non-invasive
Spirometry + BD≥12% + 200ml FEV₁Gold standard confirmation
Peak flow diary>20% variabilityIf spirometry unavailable
Challenge testPC₂₀ ≤8 mg/mlSpecialist setting only

Problem-Solving Approach

Stepwise Treatment Ladder (NICE NG80):

  1. Step 1: SABA (salbutamol/terbutaline) as-needed only
  2. Step 2: Add low-dose ICS (≤400 mcg beclometasone-equivalent daily)
  3. Step 3: Add LABA (consider MART therapy here - see below)
  4. Step 4: Increase ICS to moderate dose (400-800 mcg) OR add LTRA (montelukast)
  5. Step 5: Specialist referral + consider high-dose ICS, biologics, oral steroids

![Peak flow diary chart showing diurnal variation greater than 20 percent](Image: asthma peak flow diary)

🎯 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:

ConditionKey DiscriminatorInvestigation
AsthmaVariable symptoms, reversibilityFeNO ↑, spirometry reversible
COPDFixed obstruction, smoking Hx, age >35Post-BD FEV₁/FVC <70% persists
BronchiectasisChronic productive cough, infectionsCT chest: bronchial dilation
Cardiac failureOrthopnoea, raised JVP, oedemaBNP ↑, echo abnormal
VCDInspiratory stridor, normal FeNOFlow-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

Practice Questions: Asthma diagnosis and long-term management

Test your understanding with these related questions

A 56-year-old man presents with progressive dyspnea and chest tightness. He works in coal mining. Chest X-ray shows bilateral upper lobe nodules. What is the most likely diagnosis?

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Flashcards: Asthma diagnosis and long-term management

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Long-term oxygen therapy should not be offered to COPD patients who are _____

TAP TO REVEAL ANSWER

Long-term oxygen therapy should not be offered to COPD patients who are _____

active smokers

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