| • | GI symptoms common = crampy abdominal pain |
| • | drug induced = ACE inhibitors (captopril) |
| • | Facial edema with eosinophilia |
| • | Melkersson-Rosenthal syndrome/granulomatous cheilitis |
|
Hereditary Angioedema (HAE)
| • | painless, nonpruritic swelling of the skin |
| • | due to mutation in the C1 inhibitor gene |
| • | best screening test = C4 levels |
| • | decreased even between attacks in both type I and type II HAE |
| • | almost undetectable during attacks |
| • | if normal level during attacks, then not HAE |
| • | type I (85%) = low enzyme level– low C4, low C1-INH levels (30% below normal values) |
| • | type II (15%) = dysfunctional enzyme – low C4, normal C1-INH level (check functional assay) |
treatment:
| • | acute attack – C1-INH concentrate (if available); or fresh frozen plasma |
| • | (epinephrine, corticosteroids, antihistamines are not effective) |
| • | long-term prophylaxis – first line = danazol or stanozolol (stimulates synthesis of C1 esterase inhibitor) |
| • | danazol dose = 20-30 mg/kg/day (max = 800mg/day); may be used in children |
| • | avoid ACE inhibitors and estrogens |
Acquired Angioedema
| • | type I – associated with B-cell lymphoproliferative disorder |
| • | type II – autoantibody against C1-INH |
| • | type I pathogenesis – increased catabolism of C1-INH (an interaction between the idiotypes of monoclonal immunoglobulins and anti-idiotypic antibodies can result in consumption of c1q and C1-INH) |
| • | serum protein electrophoresis and immunopherisis |
| • | CT scan abdomen, pelvis, chest |
| • | peripheral blood lymphocyte immunophenotyping |
treatment:
| • | acute – glucocorticoids +/- epinephrine |
| • | chronic – androgens (e.g. danazol) |
ddx vs. HAE:
| • | present after 4th decade (vs. 2nd decade) |
|
C4 level
|
C1-INH level
|
C1q level
|
type I HAE
|
low
|
low
|
normal
|
type II HAE
|
low
|
normal
|
normal
|
acquired angioedema
|
low
|
low
|
low
|
ACE Inhibtor-induced Angioedema
| • | ACE inhibitors are most common cause of angioedema severe enough to require hospitalization |
| • | usually within first week of therapy |
| • | angiotensin II-receptor blockers also reported |
| • | pathogenesis – not completely known |
| • | ACE = kininase II, therefore ACE inhibitor à locally increased bradykinin levels due to decreased bradykinin metabolism (proposed mechanism) |
|
