Objectives. Hereditary angiooedema (C1-inhibitor deficiency) is a disease with protean manifestations which is often misdiagnosed initially. The purpose of this study was to delineate the clinical spectrum and course of this potentially life-threatening disease.
Setting. Ten members of two unrelated affected kindreds were repeatedly hospitalized in our service with attacks of angiooedema. Among the 271 members of the two kindreds 69 were identified who reported typical attacks.
Design and subjects. Detailed information on the clinical course and laboratory data (C1-inhibitor concentration and activity, C4 concentration) were obtained from 59 of the 69 affected subjects.
Results. C1-inhibitor concentration and activity were low in all affected patients. The disease had become manifest by age 30 years in 98%. Most patients suffered from attacks of subcutaneous swellings and abdominal pain, and half of the patients have had attacks affecting the airways. The frequency of attacks ranged from less than one to over 26 per year. Forty-two per cent had to be hospitalized at least once. Four have died of acute airway obstruction. Thirty-eight attacks in 10 patients hospitalized in our service were all treated successfully with fresh frozen plasma or with C1-inhibitor concentrate. Trauma, stress, insect stings and foodstuff were triggering factors, but the majority of attacks occurred without an identifiable trigger. Oral contraceptives and pregnancy led to worsening of symptoms. Nonetheless, all 36 pregnancies reported were carried to term. Twenty-five patients were on continuous treatment with attenuated androgens or tranexamic acid, but only seven were free of attacks in the year preceding the survey.
Conclusion. Hereditary angiooedema is an autosomal dominant disease with great variability of clinical expression and severity, even within a single kindred. It often goes unrecognized over years, and it may lead to death if, in case of impending airway obstruction, specific therapy is not instituted.