Types of Angioneurotic Edema

 

Targets of C1-inhibitor are proteases that include:

(1) complement system: C1r and C1s

(2) contact system: Factor 12a and kallikrein

(3) coagulation cascade: Factors 11a, 12a and 12f

(4) fibrinolysis: plasmin

 

Clinical features of deficiency state:

(1) sudden onset of recurrent, subepithelial swellings which are circumscribed and non-pitting and which may involve the extremities, face, mouth, larynx and bowel wall.

(2) family history in the hereditary form

(3) absence of pruritus and accompanying urticaria

(4) recurrent gastrointestinal colics, with pain, nausea, vomiting and/or watery diarrhea

(5) CNS symptoms including headaches, hemiparesis or seizures

 

Factors precipitating attacks:

(1) stress

(2) minor trauma, dental procedures or surgery

(3) insect stings

(4) food or alcohol

(5) drugs, especially angiotensin-converting enzyme (ACE) inhibitors, oral contraceptives or estrogen replacement therapy

(6) menstruation or pregnancy (associated with increased estrogen levels)

(7) nothing specific

 

Pathogenesis:

(1) hereditary (HAE)

(1a) autosomal dominant disorder with a frequency of 1 in 50,000 persons

(1b) de novo mutations

(2) acquired (AAE)

(2a) paraprotein associated (resulting in a Type I pattern)

(2b) antibodies to C1-INH, typically as autoantibodies associated with CLL or other lymphoproliferative disorder (resulting in a Type II pattern)

Type	C1-INH antigen	C1-INH functional activity	C4 Level	C1q Level
Hereditary Type I	decreased	decreased	decreased	normal
Hereditary Type II	normal or increased	decreased	decreased	normal
Acquired Type I	decreased	decreased	decreased	decreased
Acquired Type II	normal or increased	decreased	decreased	decreased

after Table 1, page 26, Ebo and Stevens (2000)