Isolated angioedema of the bowel due to C1 esterase inhibitor deficiency: a case report and review of literature

We report a rare, classic case of isolated angioedema of the bowel due to C1-esterase inhibitor deficiency. It is a rare presentation and very few cases have been reported worldwide. Angioedema has been classified into three categories. A 66-year-old Caucasian man presented with a ten-month history of episodic severe cramping abdominal pain, associated with loose stools. A colonoscopy performed during an acute attack revealed nonspecific colitis. Computed tomography of the abdomen performed at the same time showed a thickened small bowel and ascending colon with a moderate amount of free fluid in the abdomen. Levels of C4 (< 8 mg/dL; reference range 15 to 50 mg/dL), CH50 (< 10 U/mL; reference range 29 to 45 U/ml) and C1 inhibitor (< 4 mg/dL; reference range 14 to 30 mg/dL) were all low, supporting a diagnosis of acquired angioedema with isolated bowel involvement. Our patient's symptoms improved with antihistamine and supportive treatment. In addition to a detailed comprehensive medical history, laboratory data and imaging studies are required to confirm a diagnosis of angioedema due to C1 esterase inhibitor deficiency.