Treatment of Hereditary Angioedema: items that need to be addressed in practice parameter

Abstract

Background: Hereditary Angioedema (HAE) is a rare, autosomal dominant (AD) disorder caused by a C1 esterase inhibitor (C1-inh) deficiency or qualitative defect. Treatment of HAE in many parts of the world fall short and certain items need to be addressed in future guidelines.

Objective: To identify those individuals who should be on long-term prophylaxis for HAE. Additionally, to determine if prodromal symptoms are sensitive and specific enough to start treatment with C-1 INH and possibly other newly approved therapies. Also, to discuss who is appropriate to self-administer medications at home and to discuss training of such patients.

Methods: A literature review (PubMed and Google) was performed and articles published in peer-reviewed journals, which addressed HAE prophylaxis, current HAE treatments, prodromal symptoms of HAE and self-administration of injected home medications were selected, reviewed and summarized.

Results: Individuals whom have a significant decrease in QOL or have frequent or severe attacks and who fail or are intolerant to androgens should be considered for long-term prophylaxis with C1INH. Prodromal symptoms are sensitive, but non-specific, and precede acute HAE attacks in the majority of patients. Although the treatment of prodromal symptoms could lead to occasional overtreatment, it could be a viable option for those patients able to adequately predict their attacks. Finally, self-administration, has been shown to be feasible, safe and effective for patients who require IV therapy for multiple other diseases to include, but not limited to, hemophilia.

Conclusions: Prophylactic therapy, treatment at the time of prodromal symptoms and self-administration at home all should allow a reduction in morbidity and mortality associated with HAE.

Figure 1

Ability to predict HAE attacks based on prodromal symptoms. This bar graph demonstrates the percentage of individuals with HAE who are able to predict an HAE attack based on prodromal symptoms based on the study by Prematta in 2009. 6.5% of patient are able to predict the onset of an attack 100% of the time, 50% are able to predict an attack 75% of the time, 8.7% are able to predict an attack 50% of the time and 26.1% are able to predict an attack 25% of the time. Only 8.7% are unable to predict their attacks at all.

Figure 2

Time between onset of prodromal symptoms and their next HAE attack. This bar graph demonstrates the timing of acute attacks after the onset of prodromal symptoms. 45.5% of all patients had an attack within 24 hours of a prodromal symptom and 54.5% reported that their attack came 24 hours after the onset of the prodromal symptoms. However, the majority reported an attack within the first 12 hours after the onset of the prodromal symptom.