Abdominal attacks as a first manifestation of hereditary angioedema: case report

Hereditary angioedema (HAE) is a rare, life-threatening, inborn error of immunity disease, characterized by recurrent episodes of subcutaneous or submucosal edema. HAE is caused by deficient or dysfunctional C1 esterase inhibitor (C1-INH), leading to overproduction of bradykinin and the development of massive local edema. Abdominal attacks are painful, of sudden onset and often mistaken for acute abdomen leading to unnecessary surgery. Case report: A 54-years-old female at the age of 16 began experiencing recurrent episodes of severe abdominal pain combined with nausea and vomiting, as well as swelling in the extremities, face, genitalia and airways after years. The frequency of angioedema attacks varied from once a week to once a year, with the one episode lasting 1-3 days. The patient has been hospitalized several times due to extreme abdominal pain. She underwent a laparotomy in 1991 as well, but the cause of abdominal pain remained unknown. Also, no cause was found for episodes of swelling - allergic tests were negative. Therapy with antihistamines, glucocorticoids, spasmolytics and analgesics was ineffective. In January 2020, at the age of 53, she was diagnosed with HAE type I - complementary laboratory tests showed low C4 complement level (0.04 g/L), C1-INH level (<8 mg/dL) and low complement C1-INH activity (23%). Recombinant human C1-INH for on-demand treatment was initiated, with high efficiency and good tolerability. Genetic testing was performed – no pathogenic variants identified in SERPING1 (1-8 exons), ANGPT1 (exon 9), F12 (exon 9 and 10). HAE should be considered in the differential diagnosis of patients with recurrent episodes of severe, unexplained abdominal pain. Thus, abdominal HAE attacks contribute significantly to the reduced quality of life of HAE patients. Moreover, the accurate diagnosis of the disease, especially in patients who present only with recurrent abdominal symptoms, remains a challenge.