Acute Exacerbation Of Asthma

Presentation

  • Acute onset of dyspnoea and wheeze
  • Chest tightness
  • Cough


History

  • Is the patient known to have asthma?
  • Was there an identiable trigger?
  • What preventative medication is the patient on? Are they compliant?
  • Have they ever required ITU admission?


Vital signs / observations

  • Tachypnoeia
  • Tachycardia
  • Hypoxaemia (life-threatening feature)


Examination

  • Reduced conscious level (life-threatening severity)
  • Are they able to speak in full sentences?
  • Globally reduced air entry (silent chest is a life-threatening feature)
  • Wheeze
  • Is there evidence of underlying infection?


Bedside tests

  • PEFR is the most important test during an acute exacerbation of asthma
  • ABG: PCO2 ≥ 4kPa is a life-threatening feature
  • ECG


Laboratory investigations

  • WCC, CRP - ?evidence of infection
  • K+ - for monitoring, as salbutamol use can lower [K+]


Radiological investigations

  • CXR - this is not recommended by BTS guidelines, but is near universally performed


Management

Out of hospital management

  • Mild exacerbations may be managed with inhaled short-acting beta-agonists (eg salbutamol)

Immediate management

  • Nebulised salbutamol 5mg - given "back-to-back" as required
  • Nebulised ipratropium 500mcg
  • Corticosteroids: Prednisolone 30-40mg PO. IV corticosteroids (eg hydrocortisone) are only recommended if the patient is unable to swallow.
  • *Antibiotics* may sometimes be indicated if there is evidence of infection (usually amoxicillin)

If the patient fails to respond to initial therapy

  • Magnesium sulphate - 8mmol (2g) IV can be given for severe cases

If life-threatening features are present

  • Immediate ITU referral for consideration of intubation
  • NIV is not indicated in acute asthma

Ongoing management

  • Prednisolone - 5 day course in total
  • Regular salbutamol nebulisers - these can be switched to PRN as the patient improves, and thereafter discontinued
  • Ipratropium 500mcg nebulised QDS - discontinued as the patient improves
  • Complete a course of antibiotic if indicated

Prior to discharge

Follow up

  • As per BTS guidelines, all patients requiring admission for asthma exacerbations should be followed up by their GP within 2 days, and by a respiratory physician within 4 weeks
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