What is the primary management for acute hereditary angioedema?

Management of Hereditary Angioedema in Acute Setting

Plasma-derived C1 inhibitor concentrate (1000-2000 U intravenously) is the most effective first-line treatment for acute hereditary angioedema attacks and should be administered as early as possible to reduce duration and severity of symptoms. 1

Immediate Assessment and Management

• Assess for airway compromise immediately, as this is the most critical first step in managing any patient with angioedema 2
• Patients with oropharyngeal or laryngeal involvement should be closely monitored in a medical facility capable of performing intubation or tracheostomy if necessary 1, 2
• Consider elective intubation if the patient exhibits signs of impending airway closure, such as change in voice, loss of ability to swallow, or difficulty breathing 2

First-Line Treatments for Acute HAE Attacks

• Administer plasma-derived C1 inhibitor concentrate (1000-2000 U intravenously) as the primary treatment for acute attacks 1, 3
• Early treatment is critical and most effective when administered as early as possible during an attack 1, 4
• Alternative first-line options include:
  • Icatibant (30 mg subcutaneously) 1, 5
  • Ecallantide (plasma kallikrein inhibitor) - must be administered by a healthcare professional due to anaphylaxis risk 1
  • Recombinant human C1INH concentrate (rhC1INH) 1

Treatment Considerations Based on Attack Location

• Laryngeal attacks require immediate treatment and observation in a medical facility capable of airway management 1, 2
• Peripheral attacks (extremities, face) should receive prompt treatment rather than a "wait-and-see" approach 1
• Abdominal attacks may require symptomatic treatment including analgesics, antiemetics, and aggressive hydration 2

Important Cautions

• Standard angioedema treatments (antihistamines, corticosteroids, epinephrine) are NOT effective for HAE and should not be used as first-line treatment 1, 2, 5
• Delaying treatment of acute attacks, especially those involving the airway, can lead to increased morbidity and mortality 1
• Historical mortality rates for laryngeal attacks were approximately 30% without proper treatment 1

Special Populations

• For pregnant patients, plasma-derived C1INH is the only recommended acute treatment 2, 5
• For children, plasma-derived C1INH at a dose of 20 U/kg is considered safe and effective 1, 4

Self-Administration and Home Therapy

• Self-administered home therapy with C1INH concentrate has been shown to be convenient, safe, and preferred by many HAE patients 6
• All patients with HAE should have access to an effective on-demand HAE-specific agent and a contingency plan for management of acute attacks 1

Resource-Limited Settings

• In settings where first-line treatments are unavailable, fresh frozen plasma (10-15 ml/kg) may be considered for acute attacks 1, 5
• Significant disparities exist in HAE management resources between high-income and low-income countries 7

Prophylactic Considerations

• Short-term prophylaxis is indicated before dental work, surgical procedures, or invasive medical procedures 7, 1
• Plasma-derived C1INH (1000-2000 U or 20 U/kg for children) is the first-line option for short-term prophylaxis 7, 1
• For emergency procedures and in pregnant patients, administration of plasma-derived C1INH is preferred 7

The evidence clearly demonstrates that early treatment with plasma-derived C1 inhibitor concentrate significantly reduces the time to onset of symptom relief compared to placebo (0.5 vs 1.5 hours) 8, with even greater reduction for severe attacks (0.5 vs 13.5 hours) 8. This treatment has been shown to be safe and well-tolerated across multiple studies 8, 9.