| disease | Hereditary Angioedema |
It is an autosomal dominant genetic disorder that can occur at any age but is most commonly seen in early adulthood. The disease cause is a reduction or functional impairment of the C1 esterase inhibitor (an α2 globulin) in the patient's serum, leading to excessive activation of C1, uncontrolled cleavage of C4 and C2, and increased production of complement kinins. This results in elevated microvascular permeability, causing edema.
bubble_chart Clinical Manifestations
Recurrent acute cutaneous mucosal edema. ① Recurrent localized subcutaneous edema of the face, neck, trunk, and limbs. It often occurs when the area is subjected to minor trauma. The onset is sudden, with no local pain, itching, or obvious redness, and it usually resolves spontaneously within 48–72 hours. ② Laryngeal, respiratory tract, or gastrointestinal mucosal edema may occur, leading to symptoms such as dyspnea, hoarseness, suffocation, as well as abdominal pain, diarrhea, nausea, and vomiting.
bubble_chart Auxiliary Examination
① Serum C1 esterase inhibitor assay: decreased levels. A minority (10-20%) may show normal or slightly elevated levels, but with slowed electrophoretic mobility. ② C4 and C2 assays: during an attack, both C4 and C2 are significantly reduced; outside of an attack, C2 is normal while C4 remains low. ③ 50% complement hemolytic unit (CH50) is decreased.
bubble_chart Treatment Measures
1. Tranexamic acid, 1-3g/day, taken orally in 3 divided doses.
2. Antihistamines, such as chlorpheniramine, diphenhydramine, decloxizine, etc.
3. Corticosteroids can be administered orally as prednisone, intravenously as hydrocortisone, or orally/intravenously as dexamethasone.
5. Apply cold wet compresses locally.
6. In case of laryngeal edema, immediately administer 0.5mg adrenaline or 15mg ephedrine intramuscularly, and consider tracheostomy if necessary.
7. Anabolic steroids, such as danazol, metandienone, and stanozolol, can induce the synthesis of C1 esterase inhibitor, thereby preventing attacks.
