Abdominal and pelvic imaging in the diagnosis of acute abdominal attacks in patients with hereditary angioedema due to C1-inhibitor deficiency.

Introduction: Hereditary angioedema (HAE) is a rare inherited autosomal dominant disease caused by deficiency or dysfunction of C1 inhibitor (C1INH). Clinical symptoms include recurrent subcutaneous and submucosal angioedema of the internal organs. Abdominal attacks affect more than 90% of patients, are often misdiagnosed and result in unnecessary surgical procedures. Aim: To analyse the utility of imaging studies (USG, CT) in patients with C1INH-HAE during an abdominal attack and remission. Material and methods: We enrolled 40 patients with type I and II HAE (30 women, 10 men; mean age 39 years). The diagnosis of C1INH-HAE was based on patient and family history, significantly reduced values of C1INH serum level and activity. Abdominal and pelvic ultrasound were performed in patients within the first 6 h of the abdominal attack and repeated during remission. Moreover, 23 cases underwent abdominal or pelvic computed tomography during acute abdominal symptoms. The most common ultrasound and CT findings showed the transient presence of a significant amount of fluid in the free abdominal cavity and intestinal oedema during the symptom progression and spontaneously disappearing during the seizure in 90% and 50% of patients, respectively. CT revealed also an enlargement of the mesenteric lymph nodes as well as a fat stranding along the bowel wall thickening. Conclusions: Ultrasound or CT imaging facilitates the diagnosis of the patient suspected of having an abdominal attack due to C1INH-HAE. They allow to identify transitional presence of an abundant fluid in the free abdominal cavity and intestinal swelling which spontaneously disappear with a symptoms attack.