UMEM Educational Pearls

- Uniphasic anaphylaxis: occuring immediately after exposure to allergen, resolves over minutes to hours and does not recur
- Biphasic anaphylaxis: occuring after apparent resolution of symptoms typically 8 hours after the first reaction. Occur in up to 23% of adults and up to 11% of children with anaphylaxis

1. First line: IM epinephrine 1:1000 solution
   - vasoconstrictor effects on hypotension and peripheral vasodilation; bronchodilator effects on upper respiratory obstruction
   - NO absolute contraindication for use in anaphylaxis
   - Dosage: Adult: 0.3 - 0.5mg; Peds: 0.01mg/kg (max 0.3mg)
   - can be repeated every 5-15 minutes
2. Adjunctive therapy:
   - H1 Blocker: diphenhydramine 1-2mg/kg up to 50mg IV
   - H2 Blocker: ranitidine 1-2mg/kg
   - Corticosteroid: 1-2 mg/kg for prevention of biphasic reactions
   - Bronchodilator: Albuterol for bronchospasm
   - Glucagon: for refractory hypotension or if patient is on beta blocker
          - Dosage: Adult: 1-5 mg; Peds 20-30microgm/kg
          - Dose may be repeated or followed by infusion of 5-15 mg/min
   - place patient in recumbent position if tolerated with lower extremities elevated
   - supplemental O2
   - IV fluids for hypotension

Fatalities: typically seen with peanut or treenut ingestions from cardiopulmonary arrest. Associated with delayed or inappropriate epinephrine dosing

   - Mild reaction with symptom resolution: observe for 4-6 hrs (ACEP, AAP)
   - Recurrent symptoms or incomplete resolution: admit

Bonus pearl:
(For children) Follow the "Rule of 2's":
2 system involvement,
2 mg/ kg diphenhydramine
2 mg/kg ranitidine
2 mg/kg solumedrol
2 types of epi-pens available: 0.15 mg and 0.3 mg .... weight-based!

1. World Allergy Organization Guidelines for the Assessment and Management of Anaphylaxis, Feb 2011
2. Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel Oct 2010