Anaphylaxis

Question 1

What is the primary treatment for anaphylaxis?

Answer 1

Epinephrine

Anaphylaxis
0.3–0.5 mg 1:1000 IM q5-10 minutes

Anaphylactic shock refractory to IM epinephrine
0.1 mg 1:10 000 IV over 5 min

Cardiac arrest
1 mg 1:10 000 IV push

Anaphylaxis in children 0.15 mg 1:1000 IM

Question 2

A patient has an anaphylactic reaction and is successfully treated in the ER. What is your plan for discharge?

Answer 2

A SAFE discharge

SAFE STEP

Support. Ensure that there is someone to monitor patient at home

Allergen. Try to identify precipitating agent, avoid re-exposure

Follow-up. Follow-up allergy testing

Epinephrine injector. Prescribe epinephrine injector on discharge; might require 2 doses

Question 3

What is the classical presentation of anaphylaxis?

Answer 3

Urticaria or angioedema
Hypotension
Bronchospasm

Question 4

In what percentage of anaphylaxis are there no cutaneous manifestations or vasomotor instability?

Answer 4

20%

Question 5

Describe the pathophysiology of anaphylaxis.

Answer 5

Anaphylaxis is the result of immunoglobulin E–mediated mast cell degranulation, which releases inflammatory immune mediators. These mediators cause increased vascular permeability, peripheral vasodilation, increased mucus production, and bronchial smooth muscle contraction

Question 6

What is the treatment for anaphylaxis? List 4.

Answer 6

ABCs
Preparation for impending airway collapse (early intubation)
Epinephrine
Aggressive fluid resuscitation (frequently needing 5-7L)

There is no evidence for the use of histamine (H1or H2) blockers or steroids in anaphylaxis.

Question 7

What are consequences of inadvertent overdose with epinephrine?

Answer 7

Inadvertent overdose can cause coronary artery dissection, acute myocardial infarction, cardiomyopathy, arrhythmias, and death.

Question 8

What are the absolute contraindications to epinephrine in anaphylaxis?

Answer 8

There are none.

Special considerations

Patients taking β-blockers have a decreased response to epinephrine and are at risk of unopposed α activity with treatment. A half dose of epinephrine is recommended. Cocaine, tricyclic antidepressants, or monoamine oxidase inhibitors potentiate the effects of epinephrine, which might increase the risk of cardiac arrhythmias. A half dose should again be considered.7