What is the treatment for adult anaphylactic syndrome?

Treatment of Adult Anaphylactic Syndrome

Epinephrine is the cornerstone of anaphylaxis treatment and should be administered immediately as the first-line therapy to all patients with signs of anaphylaxis, especially those with hypotension, airway swelling, or difficulty breathing. 1

Initial Management

• Administer epinephrine 0.2-0.5 mg (1:1000 concentration) intramuscularly in the anterolateral thigh, which can be repeated every 5-15 minutes as needed 1
• Position the patient supine with legs elevated if hypotensive, or in a position of comfort if experiencing respiratory distress 2
• Establish intravenous access for fluid resuscitation and medication administration 1
• Provide supplemental oxygen if needed 1
• Monitor vital signs continuously, especially in patients with anaphylactic shock 1
• Arrange for immediate referral to emergency services or intensive care facility 1

Second-Line Interventions (after epinephrine)

• Administer IV fluids (crystalloids) for hypotension or shock 1
• Consider H1 antihistamines such as diphenhydramine 25-50 mg or 1-2 mg/kg parenterally, noting these are second-line agents and should never be used alone for anaphylaxis treatment 1
• Consider H2 antihistamines such as ranitidine 50 mg IV in adults (1 mg/kg in children), which may be superior when combined with H1 blockers 1
• For persistent bronchospasm despite adequate doses of epinephrine, consider nebulized albuterol 2.5-5 mg in 3 mL saline, repeated as necessary 1

Management of Refractory Anaphylaxis

• For hypotension refractory to volume replacement and epinephrine injections, consider IV epinephrine at a dose of 0.05-0.1 mg (1:10,000 solution) when IV access is available 1
• Alternatively, prepare an epinephrine infusion by adding 1 mg (1 mL) of 1:1000 epinephrine to 250 mL of D5W (concentration 4.0 μg/mL) and infuse at 1-4 μg/min, increasing to maximum of 10.0 μg/min as needed 1
• Consider vasopressor infusion (e.g., dopamine 400 mg in 500 mL D5W at 2-20 μg/kg/min) for persistent hypotension 1
• For patients on beta-blockers with refractory symptoms, consider glucagon 1-5 mg IV over 5 minutes, followed by infusion of 5-15 μg/min 1

Cardiac Arrest Management

• Implement standard BLS and ACLS protocols immediately 1
• Administer high-dose IV epinephrine: 1-3 mg (1:10,000) slowly over 3 minutes, followed by 3-5 mg over 3 minutes, then 4-10 μg/min infusion 1
• Provide rapid volume expansion 1
• Consider atropine and transcutaneous pacing if asystole or pulseless electrical activity are present 1
• Prolonged resuscitation efforts are encouraged as they are more likely to be successful in anaphylaxis 1

Additional Considerations

• Consider systemic glucocorticosteroids (e.g., methylprednisolone 1-2 mg/kg/day IV every 6 hours) for patients with history of idiopathic anaphylaxis, asthma, or severe/prolonged anaphylaxis to potentially prevent recurrent or protracted anaphylaxis 1
• Note that glucocorticosteroids are not helpful in acute management but may prevent biphasic reactions 3
• Monitor patients for biphasic reactions (recurrence without re-exposure) for at least 4-12 hours depending on risk factors for severe anaphylaxis 4
• After resolution, provide patient education, prescription for epinephrine auto-injector, and referral to an allergist 1, 4

Common Pitfalls to Avoid

• Delaying epinephrine administration - this is the most common error and contributes to fatalities 2, 5
• Using antihistamines or corticosteroids as first-line treatment instead of epinephrine 1
• Administering epinephrine intravenously in non-arrest situations without appropriate monitoring 1
• Discharging patients too early without adequate observation for biphasic reactions 1
• Failing to provide patients with an epinephrine auto-injector and proper education on its use after the acute episode 1, 4