title: Angioedema presenting as chronic gastrointestinal symptoms.
abstract: Gastrointestinal complaints may be the presenting feature of patients with acquired or hereditary angioedema. We describe two patients with episodic nausea, abdominal pain, and cramping secondary to C1 inhibitor deficiency. In one patient, an acquired deficiency arose as a paraneoplastic syndrome with abdominal complaints preceding the diagnosis of an occult lymphoma. The second patient presented at age 61 with abdominal complaints secondary to a hereditary deficiency of C1 inhibitor. The patients' symptoms were due to gastrointestinal angioedema, resulting from episodic unregulated complement activation. The biochemical mechanism of this unusual syndrome and its diagnostic importance are discussed. A C1 inhibitor deficiency should be considered in patients with unexplained abdominal symptoms suggestive of intestinal pseudo-obstruction.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor.
authors.forename: S L
authors.initials: SL
authors.lastname: Eck
authors.forename: J H
authors.initials: JH
authors.lastname: Morse
authors.forename: D A
authors.initials: DA
authors.lastname: Janssen
authors.forename: S G
authors.initials: SG
authors.lastname: Emerson
authors.forename: D M
authors.initials: DM
authors.lastname: Markovitz
mesh_terms: D015746:Abdominal Pain / Q000209:etiology*; D000328:Adult; D000799:Angioedema / Q000150:complications* / Q000235:genetics; D002908:Chronic Disease; D003167:Complement Activation; D003174:Complement C1 Inactivator Proteins / Q000172:deficiency*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000150:complications; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000209:etiology*; D009382:Neoplasms, Unknown Primary / Q000150:complications; D010257:Paraneoplastic Syndromes / Q000209:etiology
chemical_list: D003174:Complement C1 Inactivator Proteins