Hereditary Angioedema as a Cause of Recurrent Abdominal Pain

Abstract

Purpose: A 38 year-old Caucasian female with past history of diarrhea predominant irritable bowel syndrome, was admitted with 5-day history of intermittent abdominal pain, fever, nausea, vomiting, and diarrhea. Upon presentation, her examination was remarkable for dehydration, and left lower quadrant tenderness. Laboratory tests revealed WBC 10,300/mm. All other laboratory tests including liver function tests, routine stool studies, were normal. CT scan of the abdomen revealed sigmoid and descending colonic diverticula with bowel wall thickening and pericolonic stranding consistent with acute diverticulitis. Patient was started on fluids and empiric antibiotics with levofloxacin and metronidazole, without clinical or radiologic improvement. Upon further questioning, it was found that multiple family members are diagnosed with hereditary angioedema. Testing of C4 complement and C1-esterase inhibitor confirmed the diagnosis of hereditary angioedema. Patient was started on Berinert (C1-esterase inhibitor) and noted symptomatic improvement within days. Hereditary angioedema (HAE) is a rare autosomal dominant disease, characterized by a quantitative or functional defect of C1 esterase inhibitor. Type I HAE is characterized by a low or unmeasurable level of C1 inhibitor, while in type II HAE, C1 INH levels are normal but dysfunctional. Clinically, HAE is characterized by marked diffuse edema involving the skin, mucous membrane, and visceral organs. GI involvement frequently occurs in patients with HAE, and may be the initial manifestation. Isolated abdominal symptoms may occur in up to 21% of patients with HAE. The jejunum, ileum, duodenum, stomach and the colon are affected in descending frequency. Small bowel edema and abdominal ascites are common during clinical evaluation. The presence of ascites may be an indicator for the severity of an attack. Abdominal imaging reveals wall thickening of the colon as well as moderate ascites. Edema of the GI tract can occur in both hereditary and acquired forms of angioedema. In ACE-inhibitor induced angioedema of the intestine, there is primary involvement of the small bowel while in hereditary angioedema, there is isolated involvement of the colon or the small bowel. Treatment of acute attacks of HAE with IV purified C1 INH along with anti-fibrinolytics drugs has been found to be effective. Prophylactic treatment of Danazol and Stanozolol, attenuated androgens, increase the synthesis of C1 INH and are found to be the most effective prophylactic treatment. Hereditary angioedema should be considered in the differential diagnosis of unexplained, episodic abdominal pain in young patients.