Hereditary Angioedema (C1 Esterase Deficiency) 

 

 

Background

 

  • A hereditary disorder that results in angioedema without urticaria

  • Due to autosomal dominant deficiency or dysfunction of C1 esterase inhibitor → release of vasoactive mediators → vascular permeability & edema formation 

  • Presents as recurrent bouts of angioedema involving the extremities, face, oropharynx, larynx, GI, and/or GU tract lasting 24-72 hours

 

 

Considerations 

 

  • Potential acute life threatening airway edema & obstruction that is not treated by conventional methods such as steroids, epinephrine & antihistamines

  • Need to avoid triggers: oral/dental surgery, laryngoscopy, trauma, infection, stress/light anesthesia

  • Need for prophylaxis prior to surgical procedures & availability of C1 esterase inhibitor to treat acute attacks

  • Need for postop monitoring (onset may be delayed 60 mins to 36 hours after trigger)

 

 

Goals 

 

  • Pre-op prophylaxis (see management)

  • Avoid/minimize triggers

  • Gentle airway manipulation

  • Regional anesthesia if feasible

  • Ensure ready availability of treatment modalities for acute attack including difficult airway kit/surgical airway

 

 

Management 

 

  • Prophylaxis 

    • C1INHRP (C1 esterase inhibitor replacement protein)

    • Androgens (if C1INHRP not available) e.g. danazol (2.5 to 10 mg/kg per day to a maximum of 600 mg/day), beginning five days before and extending for five days after the procedure.

    • TXA (not as good as C1NHRP or Androgens)

 

  • Treatment of Acute Event 

    • C1 inhibitor concentrate (25 units/kg)

    • FFP (2-4 units) to replace the deficient enzyme

    • NOT HELPFUL: androgens, epinephrine, antihistamines, antifibrinolytics