Acquired Angioedema as Unusual Cause of Recurrent Abdominal Pain

Abstract

Acquired angioedema is a rare acquired deficiency of C1 inhibitor characterized by subcutaneous edema and/or submucosal edema of the respiratory or gastrointestinal tract. A 52-year old female with a history of chronic urticaria and recently treated Helicobacter pylori infection was admitted for recurrent epigastric abdominal pain with no new or worsening rash. Her medications included cetirizine, ranitidine, and montelukast. Laboratory work up showed normal lipase, transaminases, but mildly elevated ESR 24 mm/Hr and CRP 1.5 mg/dL. Contrast-enhanced CT abdomen showed duodenal and proximal jejunal wall thickening and mesenteric lymphadenopathy. Push enteroscopy with biopsies revealed normal duodenal and jejunal mucosa. She had multiple emergency department visits for abdominal cramping with facial swelling but without any rash, or shortness of breath. Immunological workup showed normal lymphocyte count, ANA titer 1:160, normal dsDNA, anti-Smith antibodies, normal serum immunoelectrophoresis, but low C1q complement (<5 U/mL), low C4 complement (<2 mg/dL), normal C3 complement, low C1 inhibitor (12 mg/dL) and low C1 inhibitor activity (4%); all consistent with acquired angioedema. She initially received intravenous methylprednisone and diphenhydramine without improvement, followed by fresh frozen plasma and subcutaneous icatibant 30 mg with a resolution of symptoms. Non-allergic angioedema is a rare disorder and includes medication induced and C1 inhibitor deficiency. Although mostly hereditary, C1 inhibitor deficiency can be acquired in association with lymphoproliferative disorders, infections, and autoimmune diseases. Acquired angioedema can present as chronic recurrent abdominal pain or mimic an acute surgical abdomen, even in absence of subcutaneous edema. Diagnosis is made by medical history and the level and activity of C4, C1q, and C1 inhibitor during an acute angioedema attack. Treatment options include C1 inhibitor concentrate, fresh-frozen plasma, and icatibant, which is a selective bradykinin receptor antagonist. Long-term prophylaxis is with antifibrinolytics and attenuated androgens. Our case highlights less common gastrointestinal presentation of acquired angioedema and the effectiveness of fresh frozen plasma and icatibant in its treatment. We also reiterate that early diagnosis of acquired angioedema is key for treatment of potentially life-threatening attacks and to initiate prophylaxis for recurrent attacks.2503_A Figure 1. Contrast enhanced CT abdomen showing small bowel wall (jejunal) thickening2503_B Figure 2. Push enteroscopy showing normal small bowel mucosa after resolution of acute angioedema attack