• Viral illness most common precipitant
• Allergy, drugs (esp aspirin), stress, exercise or other precipitating illness
• Beware “brittle” asthmatic who may appear “well”. May deteriorate very rapidly
• more rapid the onset the more likely to respond and less likely to admit.
• Risk of death: >3ED visits, >2 admissions, ITU/ ETT in past year, steroid use

• breathlessness, cough
• collapse

• wheeze, tachypnoea
• tachycardia, hypertension with paradox

Pneumothorax

• Oxygen
• β agonists
  • Neb Salbutamol – 5mg, continuously if sick
  • Neb Adrenaline – 1mg (esp. useful if rapid onset.)
  • IV salbutamol – only if neb's failing
• anti-cholinergic
  • Neb atropine – 500mcg. (esp for young and COPD type)
• methylxanthines
  • aminophylline – dangerous in acute asthma. Cardiotoxic, neurotoxic and causes vomiting (do not want when potential airway compromise)
• steroid
  • give early - IV rather than oral if “sick”
  • Hydrocortisone 200mg IV- reduces inflammation, increases response to β agents
• Mg SO4
  • 20mmol IV over 20min. Aim is to double serum levels.
• β agonists - β2 - bronchodilator effect
• adrenaline - β but also α effects which are useful for vasocontriction about the bronchioles, creating 'indirect' bronchodilation.