Anaphylaxis 2018

Question 1

% of patients that have an identifiable trigger for an anaphylactic reaction

Answer 1

One third

Question 2

3 ways to diagnose anaphylaxis

Answer 2

1. Acute onset with involvement of skin, mucosal tissue, or both plus 1 of: resp compromise or reduced BP/symptoms of end organ dysfunction
2. 2 or more that occur after exposure to likely allergen: skin, resp, BP/end organ, GI
3. Reduced BP after exposure to known allergen

Question 3

Epipen dosing for anaphylaxis

patients 10-25, and patients >25 kg

Answer 3

Epi dose is 0.01 mg/kg
10-25kg: 0.15mg EpiPen Jr
>25kg: 0.3mg EpiPen

Question 4

Which patients with anaphylaxis should receive fluids? What dose?

Answer 4

Cardiovascular involvement (tachycardia, hypotension, delayed capillary refill)
20 mL/kg NS bolus

Question 5

4 medications used in the treatment of anaphylaxis

Answer 5

Epinephrine
H1 and H2 antihistamines
Corticosteroids
Inhaled medications (salbutamol for lower resp sx, inhaled epi for stridor)

Question 6

How does epinephrine work in treating anaphylaxis?

Answer 6

Increases PVR and reverses vasodilation
Decreases angioedema and urticaria
B1 and B2 effects

Question 7

How do H1 and H2 antihistamines work in treating anaphylaxis? Examples

Answer 7

Mainly given to relieve the cutaneous symptoms of anaphylaxis
Ex: cetirizine, diphenhydramine, ranitidine

Question 8

Why are IV epi and glucagon used in post anaphylaxis resus?

Answer 8

IV epi: for persistent hypotension

Glucagon: for patients who regularly take beta blockers

Question 9

When do biphasic anaphylaxis reactions normally occur? How long should patients be observed in the ED?

Answer 9

Can occur from 1 to 72 hours after the first onset of symptoms
Most biphasic reactions occur in the first 4-6 hours after initial onset, so observe for this long

Question 10

What patients are more likely to have biphasic reactions?

Answer 10

Delayed administration of epi
Needed more than one dose
Presented with more severe symptoms

Question 11

What medications are prescribed on discharge to help resolve anaphylaxis symptoms?

Answer 11

3 day course of oral H1 and H2 antihistamines and oral corticosteroids