What is the immediate management for a patient with a history of allergies and anaphylaxis presenting with laryngeal edema?

Immediate Management of Laryngeal Edema in Anaphylaxis

Administer intramuscular epinephrine immediately into the lateral thigh at 0.3-0.5 mg (0.01 mg/kg in children, maximum 0.3 mg) using 1:1000 concentration—this is the single most critical life-saving intervention and should never be delayed. 1, 2

Primary Emergency Interventions

Epinephrine Administration

• Inject intramuscularly into the vastus lateralis (lateral thigh), as this provides more rapid absorption and higher plasma levels than deltoid or subcutaneous routes 1, 2
• Repeat every 5 minutes as needed if symptoms persist or progress—this interval can be shortened if clinically indicated 1
• There are no absolute contraindications to epinephrine in anaphylaxis, even in patients with cardiac disease or advanced age 1, 2
• Fatalities result from delayed epinephrine administration, not from the medication itself 1

Alternative Epinephrine Routes for Laryngeal Edema

When standard intramuscular administration is insufficient or IV access is unavailable:

• Inhaled epinephrine can be used specifically for laryngeal edema as an adjunctive measure 1
• Sublingual epinephrine may be considered if IV route cannot be obtained 1
• IV epinephrine (1:10,000 concentration) should be reserved for severe cases with cardiovascular collapse, administered slowly at 0.05-0.1 mg (50-100 mcg) 1, 2

Immediate Airway Management

Critical Airway Assessment

• Recognize early signs of difficult airway: hoarseness, lingual edema, stridor, oropharyngeal swelling, or sensation of throat closing 1, 3
• Plan immediately for advanced airway management, including surgical airway (cricothyroidotomy) when these signs are present 1

Positioning and Oxygen

• Place patient in recumbent position with lower extremities elevated to prevent orthostatic hypotension and improve venous return 1
• Administer high-flow oxygen at 6-8 L/min via face mask 1, 2
• Consider early endotracheal intubation before complete airway obstruction occurs—waiting too long makes intubation impossible 1

Secondary Interventions

Fluid Resuscitation

• Establish large-bore IV access immediately 1
• Administer normal saline 500-1000 mL rapid bolus in adults (20-30 mL/kg may be needed), as anaphylaxis can shift 35-50% of intravascular volume into extravascular space within 10 minutes 1
• Repeat fluid boluses as needed for persistent hypotension 1, 2

Adjunctive Medications (After Epinephrine)

• H1-antihistamines (diphenhydramine or chlorphenamine) IV only after adequate epinephrine and fluid resuscitation—these are not priority medications 1
• Corticosteroids (hydrocortisone IV) may prevent biphasic reactions but have delayed onset and no role in acute management 1, 2
• Avoid promethazine—it is not appropriate for anaphylaxis management 1

Refractory Cases

When Initial Epinephrine Fails (After 5-10 Minutes)

• Administer second dose of IM epinephrine (7-18% of patients require multiple doses) 1, 2
• Consider epinephrine infusion: 1 mg in 250 mL D5W (4 mcg/mL concentration), infused at 1-4 mcg/min, titrating up to 10 mcg/min 1, 2
• Add vasopressors (norepinephrine, phenylephrine, or vasopressin) for persistent hypotension despite epinephrine 1, 2

Special Considerations

• For patients on beta-blockers unresponsive to epinephrine: administer glucagon 1-5 mg IV over 5 minutes, followed by infusion at 5-15 mcg/min 2
• For persistent bronchospasm: inhaled beta-2 agonists (albuterol/salbutamol) or IV ketamine 1

Post-Acute Management

Observation Requirements

• Observe for minimum 6 hours in monitored setting after symptom resolution 1, 2
• Biphasic reactions occur in some patients and can develop up to 72 hours after initial reaction 2
• Patients requiring multiple epinephrine doses, with severe initial presentations, or delayed epinephrine administration are at higher risk for biphasic reactions 2

Disposition

• Activate emergency response system immediately—all patients with anaphylaxis require EMS transport 1
• Transfer to emergency department or intensive care facility for continued monitoring 2
• Arrange allergist-immunologist consultation for identification of trigger and prevention strategies 2

Critical Pitfalls to Avoid

• Never delay epinephrine while attempting IV access or administering antihistamines—this is the most common fatal error 1, 4
• Do not use subcutaneous epinephrine in the deltoid—absorption is inadequate 1
• Do not confuse anaphylaxis with vasovagal reaction (vasovagal presents with bradycardia, not tachycardia, and lacks urticaria) 2
• Do not rely on antihistamines or corticosteroids as primary treatment—they have no role in immediate life-threatening management 1, 4
• Avoid using epinephrine via non-parenteral routes as primary treatment—only use alternative routes when standard IM administration is impossible 1