Review Question - QID 108994

This patient with shortness of breath, hypotension, hypoxemia, and wheezing after eating at a new restaurant likely has anaphylaxis. For patients with suspected anaphylaxis, the most appropriate next step in management is administration of intramuscular epinephrine.

Anaphylaxis is an IgE-mediated, type I hypersensitivity reaction to an antigen. Signs and symptoms typically include laryngeal edema, swelling of the lips and tongue, hypotension and tachycardia (from vasodilation), and airway obstruction (from edema). The best initial step in management in anaphylaxis is IM epinephrine. Epinephrine causes bronchodilation (beta-2 agonism), increases blood pressure (alpha-1 agonism), and increases cardiac output (beta-1 agonism). After IM epinephrine is administered, further management involves securing an airway, administering IV fluids, steroids, diphenhydramine, and albuterol if needed.

Anagnostou et. al review anaphylaxis in children. They discuss the pathophysiology of the condition as well as common clinical manifestations. They recommend that patients with suspected anaphylaxis be treated immediately with intramuscular epinephrine.

Figure A demonstrates a rash consistent with urticaria, a rash often present in patients with anaphylaxis. Note the raised, erythematous appearance of the rash.

Incorrect Answers:
Answer 1: Albuterol may be used for patients with anaphylaxis and significant bronchoconstriction. However, epinephrine remains the mainstay of treatment for anaphylaxis and should be given before albuterol.

Answer 2: Cricothyrotomy may be necessary to secure a definitive airway in patients with anaphylaxis and extensive laryngeal edema preventing orotracheal intubation. However, it should not be attempted prior to administration of epinephrine.

Answer 3: Diphenhydramine may be used for patients with anaphylaxis and significant itching. However, epinephrine remains the mainstay of treatment for anaphylaxis and should be given before diphenhydramine.

Answer 5: Intubation is sometimes necessary in patients with severe anaphylaxis and worsening laryngeal edema to prevent airway obstruction. However, it should not be attempted prior to administration of epinephrine.

Bullet Summary:
The best initial step in management of anaphylaxis is IM epinephrine; further management includes IV fluids, steroids, diphenhydramine, and securing an airway if needed.