Review of Type III Non-Hereditary Angioedema Patients in Manitoba.

Introduction: Non-hereditary angioedema with normal C1 esterase inhibitor level and function (NHAE-nC1INH) is a novel entity. The diagnosis of NHAE-nC1INH requires a high index of suspicion, given that there are no laboratory tests to confirm the diagnosis. There is limited evidence on the treatment efficacy for short- and long-term prophylaxis, and acute attacks. The aim of the study is to describe a cohort of NHAE-nC1INH in Manitoba, including an estimate of prevalence, as well as to analyze the response to plasma derived C1esterase inhibitor (pdC1INH), and a bradykinin-2 receptor antagonist (Icatibant).Methods: A retrospective chart review of patients diagnosed with normal C1 esterase level and function angioedema seen at the Clinical Immunology and Allergy Clinic at the Health Sciences Centre in Winnipeg, Manitoba, was done. Inclusion criteria included the following: (1) Reside within Manitoba (2) Aged 18 years and older (3) Angioedema without urticaria (4) Normal C1-INH antigenic level and function (5) No symptom resolution with antihistamines, epinephrine or corticosteroids. (6) No family history. Five patients were included in the study who met the above inclusion criteria. The five patients charts were reviewed. Response to pdC1INH and Icatibant were defined as time to improvement of angioedema symptoms.Results: Four out of five patients had an effective response to pdC1INH for prophylactic treatment and for on-demand treatment for angioedema episodes. pdC1INH was ineffective in 1 patient for prophylaxis and on-demand treatment; tranexamic acid was successful for prophylactic treatment in 1 patient who did not respond to pdC1INH for prophylaxis and for on-demand treatment. 3 of 5 patients have tried Icatibant. All three patients were not responsive to Icatibant.Conclusion: This study suggests that pdC1INH may be an efficacious treatment option for NHAE-nC1INH patients. Larger studies are required to better elucidate the effectiveness of on-demand and prophylactic treatment for NHAE-nC1INH.