Colorectal intussusception: an unusual gastrointestinal complication of hereditary angioedema.

A 21-year-old man with a history of hereditary angioedema presented with protracted abdominal pain which failed to respond to infusion of C1 inhibitor concentrate. Evaluation by CT scan revealed extensive colorectal intussusception requiring surgical intervention. Under replacement therapy with C1 inhibitor concentrate, both the operation under general anesthesia and the postoperative phase were uneventful. The intraoperative examination suggested initiation of intussusception by local mucosal edema in the transverse colon.