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