My lips are swollen!

Hereditary Angioedema

  • Recurrent episodes of angioedema due to excessive production of bradykinin as a result of C1 inhibitor deficiency or dysfunction
  • Typically affects skin and mucosal surfaces of upper respiratory and gastrointestinal tracts
  • Laryngeal involvement can be fatal and lead to asphyxiation
  • Pruritus and urticaria are typically absent as mast cells and histamines are thought to play a minimal role
  • Potential triggers that can cause HAE attacks: dental procedures, mild trauma, menstruation, pregnancy, estrogen-containing medications
  • C1 inhibitor is an acute phase reactant and inhibitor of the classical complement and kinin-generating pathways
  • Inheritance pattern is autosomal dominant with variable clinical expression as 10% of patients are asymptomatic
  • 25% of cases are due to de novo mutations with no family history
  • Typically diagnosed by labs in the context of a suggestive clinical and familial history:
    • Low C1 esterase inhibitor antigenic and functional levels
    • Low C4 level
  • If HAE is diagnosed, consider screening other family members
  • Preventative Treatment:
    • Attenuated androgens (ie danazol, stanazol, tibolone) thought to inactivate kinins
    • Transexamic Acid
    • Regular infusions of C1 inhibitor concentrates
  • Treatment for acute attacks:
    • If laryngeal involvement, assess for airway compromise and intubate if necessary to protect airway
    • First line therapies include human derived and recombinant C1 inhibitors, bradykinin receptor antagonists
    • Second line therapy includes fresh frozen plasma and solvent/detergent-treated plasma