Acquired Angioedema Workup
- Author: Ru'aa Al Harithy, MBBS, FRCPC; Chief Editor: William D James, MD more...
Laboratory Studies
Screening is conducted by determining the C4 level, which is decreased during the attack as well as in between the attacks. If the C4 level was normal and suspicion is high, the test should be repeated. When clinical suspicion of acquired angioedema is high, qualitative and functional values of C1-INH should be obtained at the same time. Antigenic levels of C1q are usually low and are useful to distinguish hereditary angioedema from acquired angioedema.[2]
Test results for acquired angioedema types I and II are as follows:
- C1 inhibitor (C1-INH) level is low
- C1q levels is low (except 1 reported case)
- C4 and C2 levels are low
Acquired angioedema type II shows positive immunoblot assay findings for the 95-kd C1-INH cleavage product.
Other laboratory findings are related to associated illnesses.
Abdominal Radiography
During attacks of gastrointestinal edema, abdominal ultrasonography or computed tomography scanning may show edematous thickening of the intestinal wall, a fluid layer around the bowel, and large amounts of free peritoneal fluid.
Other findings may be referable to an associated illness.
Histologic Findings
Histologic findings are indistinguishable from other angioedema types. Features include sparse perivascular mononuclear cell infiltrate and reticular dermal, subcutaneous, or submucosal edema.
Vasodilation may be seen.
Caldwell JR, Ruddy S, Schur PH, Austen KF. Acquired C1 inhibitor deficiency in lymphosarcoma. Clin Immunol Immunopathol. 1972;1:39-52.
Caballero T, Baeza ML, Cabañas R, et al. Consensus statement on the diagnosis, management, and treatment of angioedema mediated by bradykinin. Part I. Classification, epidemiology, pathophysiology, genetics, clinical symptoms, and diagnosis. J Investig Allergol Clin Immunol. 2011;21(5):333-47; quiz follow 347. [Medline].
Cugno M, Zanichelli A, Foieni F, Caccia S, Cicardi M. C1-inhibitor deficiency and angioedema: molecular mechanisms and clinical progress. Trends Mol Med. Feb 2009;15(2):69-78. [Medline].
Cugno M, Castelli R, Cicardi M. Angioedema due to acquired C1-inhibitor deficiency: a bridging condition between autoimmunity and lymphoproliferation. Autoimmun Rev. Dec 2008;8(2):156-9. [Medline].
Banerji A, Sheffer AL. The spectrum of chronic angioedema. Allergy Asthma Proc. Jan-Feb 2009;30(1):11-6. [Medline].
Cicardi M, Zanichelli A. Acquired angioedema. Allergy Asthma Clin Immunol. Jul 28 2010;6(1):14. [Medline]. [Full Text].
Bouillet-Claveyrolas L, Ponard D, Drouet C, Massot C. Clinical and biological distinctions between type I and type II acquired angioedema. Am J Med. Oct 1 2003;115(5):420-1. [Medline].
Levi M, Hack CE, van Oers MH. Rituximab-induced elimination of acquired angioedema due to C1-inhibitor deficiency. Am J Med. Aug 2006;119(8):e3-5. [Medline].
Ziakas PD, Giannouli S, Psimenou E, Evangelia K, Tzioufas AG, Voulgarelis M. Acquired angioedema: a new target for rituximab?. Haematologica. Aug 2004;89(8):ELT13. [Medline].
Rottem M, Mader R. Successful use of etanercept in acquired angioedema in a patient with psoriatic arthritis. J Rheumatol. Jan 2010;37(1):209. [Medline].
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