Anaphylaxis

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Anaphylaxis is an acute life-threatening reaction that occurs within minutes of drug administration, usally parenteral.
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Epidemiology
  • 1 per 5000 exposures to penicillin
 
Clinical presentation
  • Cutaneous
    • ~urticaria and angioedema
  • Plus systemic manifestions
    • Hypotension, tachycardia
    • Respiratory distress
    • GI distress
    • Laryngeal → airway compromise
 
DDx
  • Anaphylactoid reaction
    • Not IgE mediated, but resemble anaphylaxis clinically
    • Vasodilation from the liberation of large amounts of histamine, bradykinin and/or leukotrienes
 
Labs
  • Tryptase (not routinely necessary)
 
Treatment of anaphylaxis
  • Discontinuations of the offending drug
  • Corticosteroids
  • Antihistamines
  • 1:1000 epinephrine; 0,3mL twice at 15min interval; sc. or im.
    • Patients taking beta blockers may have a limited response to epinephrine
  • Fluids and vasopressors (hypotension)
  • Aerosolized beta 2 agonists or/and aminophylline 6mg/kg over 30min (bronchospasm)
  • Cricothyroidotomy (laryngeal edema)
 
Agents for which drug desensitization protocols are published
  • Insulin
  • Penicillin
  • Heterologous antisera
  • Tetanus toxoid
  • Furosemide
  • Measles Mumps Rubella (MMR) vaccine