Hereditary Angioedema (C1 Esterase Deficiency)
Background
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A hereditary disorder that results in angioedema without urticaria
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Due to autosomal dominant deficiency or dysfunction of C1 esterase inhibitor → release of vasoactive mediators → vascular permeability & edema formation
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Presents as recurrent bouts of angioedema involving the extremities, face, oropharynx, larynx, GI, and/or GU tract lasting 24-72 hours
Considerations
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Potential acute life threatening airway edema & obstruction that is not treated by conventional methods such as steroids, epinephrine & antihistamines
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Need to avoid triggers: oral/dental surgery, laryngoscopy, trauma, infection, stress/light anesthesia
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Need for prophylaxis prior to surgical procedures & availability of C1 esterase inhibitor to treat acute attacks
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Need for postop monitoring (onset may be delayed 60 mins to 36 hours after trigger)
Goals
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Pre-op prophylaxis (see management)
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Avoid/minimize triggers
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Gentle airway manipulation
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Regional anesthesia if feasible
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Ensure ready availability of treatment modalities for acute attack including difficult airway kit/surgical airway
Management
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Prophylaxis
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C1INHRP (C1 esterase inhibitor replacement protein)
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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.
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TXA (not as good as C1NHRP or Androgens)
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Treatment of Acute Event
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C1 inhibitor concentrate (25 units/kg)
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FFP (2-4 units) to replace the deficient enzyme
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NOT HELPFUL: androgens, epinephrine, antihistamines, antifibrinolytics
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