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Congenital angioedema: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Congenital angioedema is a consequence of insufficiency (type 1, in 85% of cases) or dysfunction (type 2, in 15% of cases) of a C1-protein inhibitor that regulates complement activation along the classical pathway.
It is inherited by an autosomal dominant trait. Insufficiency of C1 inhibitor develops when complement is consumed in neoplastic processes or when autoantibodies are produced to inhibitor C1 in monoclonal gammopathies (acquired failure). Attacks are provoked by trauma, a viral infection, exacerbated by emotional stress.
Symptoms and signs are the same as with angioedema, except that edema progresses until the complement components are consumed; often affects the gastrointestinal tract, there is nausea, vomiting, colic, signs of intestinal obstruction.
The diagnosis is based on the detection of a low level of C2 and C4 (substrates of inhibitor C1), a normal C1q level (C1 fragment), and a reduced function of inhibitor C1. With type 1 disease, the level of inhibitor C1 is low; at type 2 - normal or increased. In the case of acquired inhibitor C1 deficiency, C1 level q is low.
Treatment is carried out by soluble androgens (for example, stanozolol 2 mg per os three times a day or danazol 200 mg per os three times a day) to stimulate the hepatic synthesis of the C1 inhibitor. Some experts recommend the appointment of freshly frozen plasma immediately before dental or other medical procedures for the prevention of seizures, but this approach is not used in everyday practice and can theoretically provoke seizures due to the receipt of substrates for edema. As an emergency, a purified C1 inhibitor and a recombinant C1 inhibitor are being developed.
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