Symptoms, course, and complications of abdominal attacks in hereditary angioedema due to C1 inhibitor deficiency

OBJECTIVES: Recurrent abdominal attacks belong to the cardinal and most distressing symptoms of hereditary angioedema (HAE) due to C1 inhibitor deficiency. They are characterized by crampy pain, but may include vomiting, diarrhea, and other features. Detailed clinical data about the symptoms and course of abdominal attacks have not been reported. METHODS: We retrospectively observed a total of 33,671 abdominal attacks in 153 patients with HAE including a prospectively examined subgroup of 23 patients. Symptoms, course, frequency of attacks, and complications were analyzed. RESULTS: The relation of mild, moderate, and severe attacks was 1:1.4:5.6 in the prospective part of the study. Extra-abdominal symptoms preceded the abdominal symptoms. The mean maximal pain score was 8.4 (range 1-10). Vomiting occurred in 73% (24,696) and diarrhea in 41% (13,682) of the attacks. Circulatory collapse accompanied 4.4% (1,468) of the attacks, with loss of consciousness (LOC) occurring in 2.2% (739). Nine patients could clearly distinguish two types of abdominal attacks: vomiting and diarrhea. Rare complications included tetany, hemorrhagic stools, and intussusception of the colon. In 28% (43) of the patients, recurrent abdominal attacks had started before the characteristic swelling of the skin had ever occurred. A model is proposed to classify the severity of the attacks and to describe the clinical course. CONCLUSIONS: Abdominal attacks in HAE constitute a more disabling and complex syndrome than previously assumed. Our results add to the understanding of symptoms and course of HAE and may aid in the early recognition of an impending attack and improve clinical management.