What is the initial management for angioedema?

Initial Management of Angioedema

The initial management of angioedema requires immediate airway assessment and targeted therapy based on whether it is histamine-mediated or bradykinin-mediated, with histamine-mediated angioedema requiring epinephrine, antihistamines, and corticosteroids, while bradykinin-mediated angioedema requires specific targeted therapies such as icatibant or C1 inhibitor concentrates. 1

Step 1: Airway Assessment and Management

• Maintain airway as the first priority
• Monitor oxygen saturation to maintain levels above 92% 1
• For severe cases with laryngeal involvement:
  • Consider early elective intubation if signs of airway compromise develop
  • Awake fiberoptic intubation is optimal if intubation is needed 2
  • Be prepared for emergency tracheotomy if intubation fails 1
  • Endotracheal intubation may not be necessary if edema is limited to anterior tongue and lips 2
  • Edema involving larynx, palate, floor of mouth, or oropharynx with rapid progression (within 30 min) poses higher risk of requiring intubation 2

Step 2: Determine Type of Angioedema

Histamine-mediated angioedema (typically with urticaria/hives)

• Usually associated with allergen exposure
• Often presents with pruritus
• Responds to antihistamines and corticosteroids

Bradykinin-mediated angioedema (typically without urticaria/hives)

• Includes hereditary angioedema (HAE), acquired C1 inhibitor deficiency, and ACE inhibitor-associated angioedema
• Does not respond well to antihistamines, corticosteroids, or epinephrine
• Requires specific targeted therapies 1

Step 3: Treatment Based on Type

For Histamine-mediated Angioedema:

1. Epinephrine 0.3-0.5 mg IM for severe reactions (especially with respiratory involvement) 1
2. H1 antihistamines (e.g., diphenhydramine 50 mg IV) 2, 1
3. Corticosteroids (e.g., methylprednisolone 125 mg IV) 2, 1
4. H2 blockers (e.g., ranitidine 50 mg IV or famotidine 20 mg IV) 2

For Bradykinin-mediated Angioedema:

1. For Hereditary Angioedema (HAE):

   • Icatibant 30 mg subcutaneously in abdominal area (may repeat at 6-hour intervals, not exceeding 3 injections in 24 hours) 2, 3
   • Plasma-derived C1 esterase inhibitor (20 IU/kg) 2, 1
   • Fresh frozen plasma (10-15 ml/kg) if specific treatments unavailable 1

2. For ACE inhibitor-induced angioedema:

   • Discontinue ACE inhibitor immediately 2, 1
   • Consider icatibant 30 mg subcutaneously 2
   • Supportive care 2

Special Considerations

For orolingual angioedema associated with IV alteplase:

1. Discontinue IV alteplase infusion and hold ACEIs
2. Administer IV methylprednisolone 125 mg
3. Administer IV diphenhydramine 50 mg
4. Administer ranitidine 50 mg IV or famotidine 20 mg IV
5. If angioedema increases, administer epinephrine (0.1%) 0.3 mL subcutaneously or by nebulizer 0.5 mL 2

Common Pitfalls to Avoid:

• Delaying airway management in progressive angioedema
• Relying on antihistamines and corticosteroids for bradykinin-mediated angioedema
• Failing to discontinue ACE inhibitors in patients with ACE inhibitor-induced angioedema
• Not recognizing that angioedema can be fatal if it involves the airway

Follow-up Management

• All patients with oropharyngeal or laryngeal angioedema should be observed in a facility capable of emergency airway management 1
• For recurrent angioedema, consider long-term prophylaxis options:
  • For HAE: plasma-derived C1INH replacement, lanadelumab, attenuated androgens, or antifibrinolytic agents 1
  • For ACE inhibitor-induced angioedema: avoid all ACE inhibitors permanently 1

The evidence clearly shows that prompt recognition of angioedema type and appropriate targeted therapy are essential for reducing morbidity and mortality, especially in cases with airway involvement.