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Asthma

Definition
  • Chronic inflammatory
  • Narrowing of bronchi
  • Reversible
  • Transient
Risk Factors
  • FHx
  • Parental smoking
  • Atopic syndrome
    • Eczema
    • Atopic dermatitis
    • Allergic rhinitis
  • Obesity
  • Nasal polyposis
  • GI reflux
Differential diagnosis
  • Cystic fibrosis
    • Sweat chloride?
  • COPD
    • Hyperinflation
    • Smoking Hx
  • Bronchiectasis
    • Lower lobe crackles, wheezes
    • High res. CT
  • Foreign body
  • PE
    • SOB
    • Raised JVP
  • Congestive heart failure
    • Pleural effusion
    • ECG
  • Vocal cord dysfunction
    • Inspiratory AND expiratory wheeze (sound identical)
Epidemiology
  • 4% prevalence
    • 1/10 children
    • 1/20 adults
Aetiology
  • Genetic
  • Environmental triggers
    • Allergens
    • Infections
    • Emotional
    • Cold air
    • Exercise
Clinical features
  • Dyspnoea
  • Cough
  • Recent resp. infection
  • Expiratory wheeze
  • Reduced PEV
  • Responds to short-acting beta-2 agonists
  • Creola bodies
Pathophysiology
  • Bronchial narrowing
    • Constriction
    • Mucous 
    • Oedema
  • Hyper-responsiveness
  • TH2-mediated response
    • IL-4 etc
    • Mast cells, eosinophils
    • Leukotriene release
      • Smooth muscle agonists
  • Potential for long-term changes
    • fixed muscle contraction
Investigations
  • Spirometry
  • PEF
Management

a) conservative
  • Smoking cessation
  • Allergen avoidance
b) medical
  • Short-acting relievers
    • Salbutamol
  • Long-acting inhaled relief
    • Steroids
    • B2 agonists
  • Oral corticosteroids
  • Leukotriene receptor antagonists
c) surgical

Prognosis
  • Life expectancy normal
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