What to do in a case of angioedema?

Management of Angioedema

In cases of angioedema, immediate assessment of airway patency is critical, with early elective intubation considered if signs of airway compromise develop, particularly in cases involving the larynx, palate, floor of mouth, or oropharynx with rapid progression. 1

Initial Assessment and Classification

First, determine the type of angioedema:

1. Histamine-mediated angioedema:

   • Presents with urticaria (hives) and pruritus
   • Rapid onset (minutes)
   • Often associated with allergen exposure

2. Bradykinin-mediated angioedema:

   • No urticaria
   • Slower onset (hours)
   • Includes:
     • Hereditary angioedema (HAE)
     • Acquired C1 inhibitor deficiency
     • ACE inhibitor-associated angioedema

Airway Management

• Monitor oxygen saturation to maintain levels above 92% 1
• Do not directly visualize the airway as trauma from the procedure can worsen angioedema 2
• All patients with oropharyngeal or laryngeal angioedema should be observed in a facility capable of emergency airway management 1
• If signs of impending airway closure develop (change in voice, difficulty swallowing, breathing difficulty), consider elective intubation 2
• Ensure immediate availability of backup tracheostomy in case intubation fails 2

Treatment Based on Angioedema Type

For Hereditary Angioedema (HAE):

1. First-line treatments:

   • Icatibant 30 mg subcutaneously in abdominal area (may repeat at 6-hour intervals, not exceeding 3 injections in 24 hours) 1, 3
   • Plasma-derived C1 esterase inhibitor (20 IU/kg) 1

2. Alternative treatment (if first-line unavailable):

   • Fresh frozen plasma (10-15 ml/kg) 1
   • Note: Fresh frozen plasma might acutely exacerbate some attacks, so caution is required 2

For Histamine-mediated Angioedema:

• H1 antihistamines (e.g., diphenhydramine 50 mg IV) 1
• Corticosteroids (e.g., methylprednisolone 125 mg IV) 1
• Epinephrine may provide temporary benefit through vasoconstriction but does not change the overall course of an attack 2

For ACE Inhibitor-induced Angioedema:

• Immediately discontinue the ACE inhibitor 1
• Supportive care with airway management
• Consider icatibant, though evidence is variable 4

Symptomatic Management

• Extremity attacks: No specific symptomatic therapy
• Genitourinary attacks: Pain medication if severe; catheterization if unable to urinate
• Abdominal attacks:
  • Narcotic medications for pain control
  • Antiemetics for nausea and vomiting
  • Aggressive hydration (third-space sequestration is common) 2

Long-term Prophylaxis for HAE

Options include:

1. Plasma-derived C1INH replacement
2. Lanadelumab
3. Anabolic androgens (e.g., danazol)
   • Start with low or high dose based on patient needs
   • Titrate to lowest effective dose
   • Do not change dosage faster than once per week 2
4. Antifibrinolytic agents 1

Short-term Prophylaxis for HAE

For patients undergoing procedures likely to trigger attacks:

1. Fresh frozen plasma
2. C1INH replacement
3. Short-term, high-dose anabolic androgen therapy (6-10 mg/kg/d in divided doses to maximum 200 mg of danazol or equivalent) for 5-10 days before procedure 2

Important Caveats

• Neither anabolic androgens nor antifibrinolytic drugs provide reliably effective treatment for acute attacks 2
• Corticosteroids and antihistamines have no beneficial effect on HAE attacks 2
• Avoid narcotic addiction risk in patients with frequent abdominal attacks 2
• All patients with HAE should have access to an effective, on-demand HAE-specific agent 2
• Estrogen-containing contraceptives should be avoided in women with HAE 1
• ACE inhibitors should be avoided in patients with any form of bradykinin-mediated angioedema 1

Special Considerations in Pregnancy

• Androgens are contraindicated
• Plasma-derived C1INH is the preferred treatment
• Attacks may increase during pregnancy but typically decrease during delivery 1

The management of angioedema requires prompt identification of the type and initiation of appropriate treatment to improve outcomes. Airway management remains the most critical intervention in severe cases, regardless of angioedema type.