COPD vs. Asthma

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COPD vs Asthma

COPDAsthma
SmokerAlmost allMaybe
<35yRareOften
Chronic productive coughCommonRare
BreathlessPersistent and progressiveVariable
Night time breathlessness or wheezeRareCommon
Day to day variationRareCommon
If any doubt, consider reversibility testing.

Spirometry

Restrictive pattern

  • Examples – fibrosing alveolitis, scoliosis
  • FVC < 80%
  • FEV1 reduced
  • FEV1/FVC normal

Obstructive pattern

  • COPD
    • FEV1/FVC < 0.7
    • FEV1 < 80%
      • Mild 50-80%
      • Moderate 30-49%
      • Severe < 30%
    • Reversibility test only if diagnostic doubt or asthma co-existing
      • COPD excluded if
        • FEV1/FVC & FEV1 returns normal after bronchodilator
      • Consider asthma if
        • Large (>400ml) FEV1 response to bronchodilator
  • Asthma
    • High probability – Treatment and review
    • Intermediate – Reversibility spirometry
      • FEV1/FVC < 0.7
      • FEV1 < 80%
      • Large (>400ml) FEV1 response to bronchodilator
    • Low probability – Consider alternative diagnosis [reconsider diagnosis if other causes excluded]
    • PEFR logs
      • >60 l/min is significant reversibility
      • Look for daily or diurnal variations
      • > 20% variation is of significance