From the Guidelines
Anaphylactic shock is a severe, potentially life-threatening allergic reaction requiring immediate medical attention, and the first-line treatment is epinephrine administered intramuscularly in a dose of 0.01 mg/kg of a 1:1000 solution to a maximum of 0.5 mg in adults and 0.3 mg in children, as recommended by the most recent guidelines 1. The clinical criteria proposed by the National Institute of Allergy and Infectious Diseases (NIAID) continue to provide a helpful framework in approaching patients with acute allergic symptoms, and fulfilling diagnostic criteria is not a prerequisite for epinephrine administration in a patient experiencing an acute allergic reaction 1. Some key points to consider in the management of anaphylactic shock include:
- Administering epinephrine via an auto-injector like EpiPen into the outer thigh muscle immediately, then calling emergency services (911) 1
- Positioning the person flat on their back with legs elevated unless they're having breathing difficulties, in which case they should sit up
- Giving additional doses of epinephrine every 5-15 minutes if symptoms persist
- Providing oxygen, IV fluids, antihistamines (like diphenhydramine 25-50mg), corticosteroids (like methylprednisolone 125mg), and possibly bronchodilators in a hospital setting 1
- Observing patients for 4-8 hours after recovery as symptoms can return Anaphylactic shock occurs when the immune system overreacts to an allergen, releasing chemicals that cause blood vessels to dilate rapidly, blood pressure to drop dangerously, and airways to constrict, and common triggers include certain foods, medications, insect stings, and latex 1. It is essential to note that antihistamines and glucocorticoids should not be administered before, or in place of, epinephrine, as they have a slower onset of action and are less effective in treating acute symptoms 1. Overall, the management of anaphylactic shock requires prompt recognition and treatment with epinephrine, as well as supportive care and monitoring for potential complications.
From the FDA Drug Label
1 INDICATIONS & USAGE Adrenalin® is available as a single-use 1 mL vial and a multiple-use 30 mL vial for intramuscular and subcutaneous use. Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis.
The signs and symptoms associated with anaphylaxis include flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with hypotension, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, airway swelling, laryngospasm, bronchospasm, pruritus, urticaria or angioedema, swelling of the eyelids, lips, and tongue.
Anaphylactic shock is a severe, life-threatening allergic reaction that requires immediate medical attention. The drug label for epinephrine (IM) indicates that it is used for the emergency treatment of allergic reactions (Type I), including anaphylaxis. The label lists the signs and symptoms associated with anaphylaxis, which include:
- Flushing
- Apprehension
- Syncope
- Tachycardia
- Thready or unobtainable pulse associated with hypotension
- Convulsions
- Vomiting
- Diarrhea and abdominal cramps
- Involuntary voiding
- Airway swelling
- Laryngospasm
- Bronchospasm
- Pruritus
- Urticaria or angioedema
- Swelling of the eyelids, lips, and tongue Epinephrine (IM) is used to treat these symptoms, as stated in the drug label 2.
From the Research
Definition and Symptoms of Anaphylactic Shock
- Anaphylaxis is a multisystem disorder that can manifest signs and symptoms related to the cutaneous, respiratory, cardiovascular, and gastrointestinal systems 3.
- Symptoms are rapid in onset and death can occur within minutes 3.
Treatment of Anaphylactic Shock
- Epinephrine is the cornerstone of anaphylaxis management and should be administered immediately upon evidence of the occurrence of anaphylaxis 4, 3.
- The most appropriate administration is 0.3 to 0.5 mL of 1:1000 dilution intramuscularly for adults and 0.01 mg/kg for children, given in the lateral thigh 4.
- For patients unresponsive to repeated intramuscular injections, a continuous infusion of epinephrine should be started 3.
- Antihistamines and corticosteroids are second-line medications and should never be given in lieu of, or prior to, epinephrine 3.
- Aggressive fluid resuscitation should also be used to treat the intravascular volume depletion characteristic of anaphylaxis 3.
Administration of a Second Dose of Epinephrine
- There are instances where a single dose of epinephrine does not relieve symptoms and a second dose may be required to further mitigate symptoms and preserve life 5.
- It is reasonable to administer a second dose when symptoms of severe anaphylaxis fail to resolve following an initial dose 5.
- Further research is needed to better identify individuals who may benefit from a second dose of epinephrine 5.
Emergency Department Treatment
- Intramuscular epinephrine is the immediate treatment of all patients with anaphylaxis 6, 7.
- Intravenous epinephrine should be used in patients in shock, either as a bolus or infusion, along with fluid resuscitation 6, 7.
- Airway obstruction must be recognized, and early intubation may be necessary 6, 7.
- Disposition depends on patient presentation and response to treatment, and mandatory observation periods are not necessary 6, 7.