Is there a need for clinical guidelines in the United States for the diagnosis of hereditary angioedema and the screening of family members of affected patients?

Hereditary angioedema diagnosis evaluation score (HADES): A new clinical scoring system for predicting hereditary angioedema with C1 inhibitor deficiency

Background

Diagnosis of hereditary angioedema (HAE) poses challenges because of its rarity and its overlapping symptoms with allergic and gastrointestinal conditions, resulting in misdiagnosis.

Objective

We developed a predictive score using clinical variables for suspected HAE patients with C1 inhibitor deficiency (HAE-C1INH) to increase suspicion of HAE and thus improve diagnosis.

Methods

The HADES (HAE diagnosis evaluation score) study used a nationwide retrospective cohort of individuals with suspected HAE-C1INH in Argentina. A questionnaire was designed to collect relevant clinical information on possible predictors for HAE. Blood samples were analyzed for C1-INH/C1q levels and C1-INH function. A predictive score was developed from the odds ratios derived from multivariate logistic regression analysis.

Results

The study included 2423 individuals (1642 suspected index cases and 781 family cases). Only patients with confirmed HAE types I or II (n = 499) were included in the final analysis; acquired angioedema/F12 gene variants were excluded. Eight clinical variables were identified as independent predictors of HAE: age at onset ≤20 years, recurrent limb edema, abdominal pain, vomiting, trauma as a trigger, absence of wheals, family history of angioedema, and recurrent edema lasting ≥24 hours. The predictive score demonstrated favorable performance in identifying HAE cases within the index population (range, 0-18.5), with low scores (1.5-6.5) associated with high sensitivity (100%) and negative predictive value (100%), and high scores (≥15) associated with high specificity (99.4%) and positive predictive value (75.0%).

Conclusions

The predictive HADES offers a simple and efficient method for improving testing for suspicion of HAE by using clinical parameters. Further validation studies are required to confirm its reliability and accuracy.

A human centred innovative approach based on persona in hereditary angioedema

BACKGROUND

Hereditary Angioedema (HAE) due to C1-inhibitor deficiency (C1INH) is a rare condition, clinically characterised by recurrent swelling. The unpredictability of attacks affects the patients' quality of life (QoL). HAE patients and their families have vast unmet physical, psychological, and social needs. A human-centred design (HCD) approach to describing the needs of different user types is to utilise personas, a data-driven narrative tool for communicating user archetypes that capture the individuals' attitudes, goals, and behaviours. The aim of this study was to create and analyse personas based on HAE patients' and their caregivers' interviews. Semi-structured interviews were conducted through anthropological conversations with patients, patient-caregivers (double role of patient and caregiver), and non-affected caregivers. Qualitative and quantitative insights from analyses formed the basis to create personas.

RESULTS

We enrolled 17 subjects: 15 patients (6 of them were patient-caregivers) and 2 non-affected caregivers. The mean age of participants was 50.3 ± 14.4 years. Eight patients were on treatment with prophylactic therapy. The mean percentage score of Angioedema Quality of Life (AE-QoL) for HAE patients was 19.8 ± 12.0. Six personas were identified describing the participants' personal history, disease management, and needs: four personas referred to patients, one to patient-caregivers, and one non-affected caregiver personas were identified. Across patient personas, the most expressed needs were psychological support and better awareness amongst healthcare professionals. Caregivers, on their side, desired better information about the disease, including the latest therapies, and higher awareness within the community.

CONCLUSION

A Human Centred Innovative Approach Based on Persona extends beyond the physical symptoms to encompass the psychological and social aspects of the individual's well-being also including the family in the evaluation.

An Overview of Hereditary Angioedema for the Primary Care Physician

Hereditary angioedema is a rare autosomal dominant condition characterized by episodes of swelling of the upper airway, intestines, and skin. The disorder is characterized by deficiency in C1 esterase inhibitor (C1-INH) or a decrease in functional C1-INH. Treatment options include on demand therapy (treatment of acute attacks), long-term prophylaxis, and short-term prophylaxis. Corticosteroids, epinephrine, and antihistamines are not effective for this form of angioedema. The high mortality in patients undiagnosed underscores a need for broader physician awareness to identify these patients and initiate therapy.

Hereditary angioedema in Spain: medical care and patient journey

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1INH) is a genetic rare disease characterized by recurrent, transient and unpredictable episodes of cold, non-pruriginous oedema without associated urticaria. The characteristics of the disease have a considerable impact on the quality of life of patients. The aim of this study was to increase understanding of the patient journey of HAE in Spain.

METHODS

A multidisciplinary committee of 16 HAE experts (allergy, immunology, emergency department, hospital pharmacy and nursing) and 3 representatives of the Spanish Hereditary Angioedema Patient Association (AEDAF) who were patients or caregivers participated in the study. A review of the publications on HAE treatment was performed. Semi-structured interviews were performed to HAE experts, patients, or caregivers. Three meetings with the experts, patients and caregivers were held to share, discuss, and validate data obtained from literature and interviews and to build the model.

RESULTS

Throughout the project, the patient journey has been drawn up, dividing it into the stages of pre-diagnosis, diagnosis and treatment/follow-up. Some areas for improvement have been identified. Firstly, there is a need to enhance awareness and training on HAE among healthcare professionals, with a particular emphasis on primary care and emergency department personnel. Secondly, efforts should be made to minimize patient referral times to allergy/immunology specialists, ensuring timely access to appropriate care. Thirdly, it is crucial to encourage the study of the relatives of diagnosed patients to early identify potential cases. Fourthly, equitable access to self-administered treatments should be ensured, facilitated by systems that enable medication delivery at home and proper education and training for patients. Equitable access to long-term prophylactic treatment should also be prioritized for all patients in need. To standardize HAE management, the development of consensus guidelines that reduce variability in clinical practice is essential. Lastly, promoting research studies to enhance knowledge of the disease and align its treatment with new developments in the healthcare field should be encouraged.

CONCLUSIONS

The knowledge of the patient journey in HAE allowed us to identify improvement areas with the final aim to optimize the disease management.

Hereditary angioedema classification: Expanding knowledge by genotyping and endotyping

Hereditary angioedema (HAE) encompasses a group of diseases characterized by recurrent, genetically mediated angioedema associated with increased vascular permeability primarily due to bradykinin. The disease poses diagnostic challenges, leading to underdiagnosis and delayed therapy. Severe manifestations include laryngeal and intestinal angioedema, contributing to significant morbidity and mortality. If left undiagnosed, the estimated mortality rate of the disease ranges from 25% to 40% due to asphyxiation caused by laryngeal angioedema. There is a pressing need to enhance awareness of hereditary angioedema and its warning signs. The acronym "H4AE" may facilitate the memorization of these signs. This study comprehensively reviews clinical, laboratory, and physiopathological features of documented HAE subtypes. The study advocates for an improved HAE classification based on endotypes, building on the knowledge of angioedema pathophysiology. The proposed endotype classification of HAE offers a clear and applicable framework, encouraging advancements in disease understanding and classification.

Evaluation of the Retrospective LACE Index in Predicting the Risk of Readmission in Patients with Hereditary Angioedema in an Emergency Department

This study aimed to calculate the LACE index in patients who admitted to the emergency department (ED) with hereditary angioedema (HA) diagnosed and to predict recurrent admissions of patients. In this single-center study, patients aged 18 or higher who were admitted to the ED diagnosed with HA were included over a 12-year period. 35 patients diagnosed with code E88.0 were evaluated according to electronic file records. The number of admissions to the ED in the last 6 months was 2. The LACE index was 4, and risk was 71.4%. The patients admitted to the hospital in the last 30 days had a higher rate of admission to the hospital in the last 6 months (p < 0.001). The LACE index at admission predicted 30 days admission with (AUC = 0.75, 95% CI (0.56-0.91)) acceptable discrimination. The LACE index and the number of admissions in the last 6 months included in the evaluation can be considered predictive in recurrent ED admissions of HA patients. However, the distribution of LACE-risk groups is no priority. Therefore, the low-, medium-, or high-risk level of LACE index values should be not taken into consideration in readmission of such patients.

The multifactorial impact of receiving a hereditary angioedema diagnosis

Hereditary angioedema (HAE) is a rare, chronic, debilitating genetic disorder characterized by recurrent, unpredictable, and potentially life-threatening episodes of swelling that typically affect the extremities, face, abdomen, genitals, and larynx. The most frequent cause of HAE is a mutation in the serpin family G member 1 (SERPING1) gene, which either leads to deficient plasma levels of the C1-esterase inhibitor (C1-INH) protein (type I HAE-C1-INH) or normal plasma levels of dysfunctional C1-INH protein (type II HAE-C1-INH). Mutations in SERPING1 are known to be associated with dysregulation of the kallikrein-bradykinin cascade leading to enhancement of bradykinin production and increased vascular permeability. However, some patients present with a third type of HAE (HAE-nl-C1-INH) that is characterized by normal plasma levels and functionality of the C1-INH protein. While mutations in the factor XII, angiopoietin-1, plasminogen, kininogen-1, myoferlin, and heparan sulfate-glucosamine 3-O-sulfotransferase-6 genes have been identified in some patients with HAE-nI-C1-INH, genetic cause remains unknown in many cases with further research required to fully elucidate the pathology of disease in these patients. Here we review the challenges that arise on the pathway to a confirmed diagnosis of HAE and explore the multifactorial impact of receiving a HAE diagnosis. We conclude that it is important to continue to raise awareness of HAE because delays to diagnosis have a direct impact upon patient suffering and quality of life. Since many patients will seek help from hospitals during their first swelling attack it is vital that emergency department staff are aware of the different pathological pathways that distinguish HAE from other forms of angioedema to ensure that the most appropriate treatment is administered. As disease awareness increases, it is hoped that patients will be diagnosed earlier and that pre-authorization and insurance coverage of HAE treatments will become easier to obtain, ultimately reducing the burden of treatment for these patients and their caregivers.

Hereditary Angioedema

Hereditary angioedema is a rare autosomal dominant condition characterized by episodes of swelling of the upper airway, intestines, and skin. The disorder is characterized by deficiency in C1 esterase inhibitor (C1-INH) or a decrease in functional C1-INH. Treatment options include on demand therapy (treatment of acute attacks), long-term prophylaxis, and short-term prophylaxis. Corticosteroids, epinephrine, and antihistamines are not effective for this form of angioedema. The high mortality in patients undiagnosed underscores a need for broader physician awareness to identify these patients and initiate therapy.

Managing Diagnosis, Treatment, and Burden of Disease in Hereditary Angioedema Patients with Normal C1-Esterase Inhibitor

Hereditary angioedema (HAE) is a rare, chronic, and debilitating genetic disorder characterized by recurrent and unpredictable swelling episodes that primarily affect the subcutaneous and/or submucosal tissues of the extremities, larynx, face, abdomen, and genitals. Most cases of HAE are caused by mutations in the serpin family G member 1 gene (SERPING1), which encodes C1-esterase inhibitor (C1-INH) protein. Mutations in SERPING1 lead to deficient (type I HAE-C1-INH) or dysfunctional (type II HAE-C1-INH) C1-INH protein and subsequent dysregulation of the kallikrein-bradykinin cascade. However, some patients present with a third type of HAE (HAE-nI-C1-INH), which was first described in the year 2000 and is characterized by an absence of mutations in SERPING1. Although mutations in the coagulation factor XII, angiopoietin-1, plasminogen, kininogen-1, myoferlin, and heparan sulfate-glucosamine 3-O-sulfotransferase-6 genes have been identified in some patients with HAE-nI-C1-INH, genetic cause is still unknown in many cases, hindering full elucidation of the pathology of this HAE subtype. Diagnosis of HAE-nI-C1-INH is also further complicated by the fact that patients typically demonstrate normal plasma levels of C1-INH and complement component 4 protein and normal C1-INH functionality during laboratory analysis. Therefore, we review the challenges associated with diagnosing, treating, and living with HAE-nI-C1-INH. We conclude that raising awareness of the presenting features of HAE-nI-C1-INH within the clinical setting and among the general public is critical to aid earlier suspicion and diagnosis of the disease. Furthermore, adopting an individualized approach to HAE-nI-C1-INH treatment is essential to help address the current and significant unmet needs in this patient population.

Clinical features of hereditary angioedema and warning signs (H4AE) for its identification

OBJECTIVES

The study describes a case series of hereditary angioedema with C1 Inhibitor Deficiency (C1INH-HAE) in order to corroborate six clinical warning signs "HAAAAE (H4AE)" to enable early identification of this disease.

METHODS

The authors analyzed the C1INH-HAE cohort to analyze the clinical aspects of the present study's patients and corroborate the six clinical warning signs of the Hereditary Angioedema Brazilian Guidelines. Data regarding demographics, the onset of disease, time to diagnosis, frequency of attacks per year, organs involved, triggers, crisis duration and their outcomes, and disease treatment were collected. Then the authors developed an acronym, H4AE, to help healthcare professionals remember the warning signs.

RESULTS

The authors included 98 patients in the study, with a mean age of 38.1 years, 67.3% being female, and 75.3% with a family history of HAE. HAE diagnosis was delayed, on average, 13.7 years after its initial manifestation. Exploratory laparotomy was reported by 26.9%, and orotracheal intubation by 21.3% of the present study's patients; 61.3% and 30.3% of them were admitted at least once in the hospital and in the intensive care unit, respectively. The authors constructed an acronym "H4AE" with the six warning signs of HAE: Hereditary, recurrent Angioedema, Abdominal pain, Absence of urticaria, Absence of response to antihistamines, Estrogen association.

CONCLUSION

C1INH-HAE is still underdiagnosed and associated with high morbidity. The study showed clinical features of this disease, corroborating the warning signs, which may be useful in raising awareness and improving the diagnosis of C1INH-HAE. The authors suggest the acronym "H4AE" to remind the warning signs.

The diagnosis and treatment of hereditary angioedema patients in Japan: A patient reported outcome survey

BACKGROUND

The rate at which patients are accurately diagnosed with hereditary angioedema (HAE), as well as diagnosed patients access to modern treatments differs greatly among countries. Moreover, the severity and burden of HAE on patients have been reported mostly on the basis of physician-reported surveys. To gain insight into the real-world conditions of patients with HAE through a patient-reported survey in Japan and identify any unmet needs.

METHODS

A questionnaire was distributed to 121 patients with HAE via a Japanese HAE patient organization during 2016-2017. Responses were collected from 70 patients (57.9%) and subjected to analysis.

RESULTS

The average periods from the initial appearance of symptoms (e.g. edema) to a HAE diagnosis was 15.6 years (min-max, 0-53). Patients visited an average of 4.6 different departments until receiving a definitive diagnosis. The average age at the first visit was 25.6 years (3-73) and at diagnosis 32.8 years (0-73). Patients reported an average of 15.7 (0-100) attacks per year, but only 53.1% of attacks were treated. The days of hospitalization due to severe attacks was 14.3 (0-200) before diagnosis, but these declined to 4.3 (0-50) after diagnosis. In the treatment for attacks, 82% of the patients were treated with the plasma-derived C1 inhibitor concentrate, and 69% of the patients reported experiencing a therapeutic effect.

CONCLUSIONS

There is a long gap between first attack and diagnosis of HAE, and the number of non-treated attacks is high in Japan. Steps are needed to improve the diagnostic and treatment environments to address these issues.

Unnecessary Abdominal Surgeries in Attacks of Hereditary Angioedema with Normal C1 Inhibitor

Hereditary angioedema (HAE) is an autosomal dominant disease mostly due to the deficiency of C1 inhibitor (C1-INH). HAE with normal C1-INH was first described in 2000 and associated with mutations in the coagulation factor XII in 2006. Both diseases are associated with high bradykinin production, resulting in increased vascular permeability. Gastrointestinal edema due to HAE can be misdiagnosed as acute abdomen and unnecessary surgical procedures may be performed. The present study evaluates the prevalence of surgical procedures and/or acute abdomen in HAE patients with the coagulation factor XII mutation. It is a retrospective study where patients were diagnosed with recurrent angioedema without urticaria, normal C1-INH levels, and positive family history of angioedema. All patients were evaluated for the known mutations located at exon 9 of the F12 gene. Medical records were evaluated and questionnaires were applied to 52 patients with normal C1-INH levels (age range 13-76 years; 47/52, 90.38% women; 5/52, 9.61% men). F12 mutation was present in 32/52 patients (61.5%). Acute abdominal pain was diagnosed in 16/52 (30.76%) patients, appendicitis in 9/16 (56.2%), and undetermined diagnosis in 7/16 (43.7%). Among patients diagnosed with acute abdominal pain, 13/16 (81.2%) underwent surgery and 3/16 (18.7%) improved without surgical intervention. We conclude that many HAE patients with coagulation factor XII mutation were misdiagnosed with acute abdomen and subjected to unnecessary invasive procedures. It is critical to disseminate information about this rare mutation in patients with otherwise normal C1-INH activity, in order to speed up diagnosis and avoid misconduct.

Hereditary angioedema: Epidemiology and burden of disease

<title/> Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder characterized by swelling of subcutaneous, mucosal, and submucosal tissue without associated pruritus or wheals caused by a temporary localized increase in vascular permeability. Swelling attacks primarily affect the cutaneous tissue, abdominal viscera, genitals, or airways. <title/> Reports of the prevalence of HAE C1 inhibitor (C1-INH) deficiency varies widely, from 1:50,000 to 1:100,000. The prevalence of HAE normal C1-INH is unknown but is likely much lower than HAE C1-INH. Approximately one-third of patients with recurrent angioedema without wheals have HAE. <title/> The burden of disease for patients with HAE is substantial. Attacks are unpredictable with respect to frequency, severity, and the site that swells. Laryngeal attacks can be fatal if not treated promptly and appropriately. Feelings of stress, anxiety, and depression can trigger attacks, and begin a cycle of attacks that cause anxiety that, in turn, triggers further attacks. Despite full physical recovery between attacks, patients often experience continual emotional impairment and reduced quality of life (QoL). Absenteeism from work and presenteeism at work or educational activities for patients and caregivers increase stress and reduce productivity during and between attacks. Missed opportunities for career development are common. <title/> Significant advances have been made in the past decade to expand both acute and prophylactic treatment options for patients with HAE, lowering both the disease and treatment burden, and improving the QoL of patients with HAE.

Experience with Intravenous Plasma-Derived C1-Inhibitor in Pregnant Women with Hereditary Angioedema: A Systematic Literature Review

Consensus guidelines recommend plasma-derived C1 inhibitor (C1-INH) as first-line treatment in pregnant women with hereditary angioedema (HAE). We conducted a systematic review of the literature that describes experience with plasma-derived C1-INH during pregnancy. A literature search of PubMed was conducted in November 2018 using variants of "hereditary angioedema" and "pregnancy." English language articles that presented original data about the use of plasma-derived C1-INH during pregnancy were selected for data extraction. The search returned 253 unique records, of which 40 described the use of C1-INH during pregnancy (91 patients, 136 pregnancies). When the number of doses was reported, a total of 1562 doses were administered ranging from 500 to 3000 IU. Infusions were administered during all 3 trimesters and were most commonly administered during the third trimester. Overall, 1,490,500 IU of plasma-derived C1-INH were administered during pregnancy. Of the 128 fetuses for which outcomes were reported, 3 (2%) resulted in spontaneous abortion, 1 (1%) was stillborn, and 1 (1%) was a vanishing twin. Use of plasma-derived C1-INH in women with HAE during pregnancy has been widely reported in the scientific literature and has a favorable safety profile, supporting treatment guideline recommendations.

HEREDITARY ANGIOEDEMA DUE TO C1-INHIBITOR DEFICIENCY IN PEDIATRIC PATIENTS IN CROATIA - FIRST NATIONAL STUDY, DIAGNOSTIC AND PROPHYLACTIC CHALLENGES

Hereditary angioedema (HAE) is a rare autosomal dominant disease with deficiency (type I) or dysfunction (type II) of C1 inhibitor, caused by mutations in the C1-INH gene, characterized by recurrent submucosal or subcutaneous edemas including skin swelling, abdominal pain and life-threatening episodes of upper airway obstruction. The aim of this study was to investigate healthcare experiences in children with HAE due to C1 inhibitor deficiency (C1-INH-HAE) in Croatia in order to estimate the number of affected children and to recommend management protocols for diagnosis, short-term prophylaxis and acute treatment. Patients were recruited during a 4-year period at five hospitals in Croatia. Complement testing was performed in patients with a positive family history. This pilot study revealed nine pediatric patients positive for C1-INH- HAE type I, aged 1-16 years, four of them asymptomatic. Before the age of one year, C1-INH levels may be lower than in adults; it is advisable to confirm C1-INH-HAE after the age of one year. Plasma-derived C1-INH is recommended as acute and short-term prophylactic treatment. Recombinant C1-INH and icatibant are licensed for the acute treatment of pediatric patients. In Croatia, HAE is still underdiagnosed in pediatric population.

Hereditary angioedema with C1 inhibitor (C1-INH) deficit: the strength of recognition (51 cases)

Hereditary angioedema (HAE) is a rare autosomal dominant disease due to C1 esterase inhibitor deficiency (C1-INH). The disease is characterized by subcutaneous and submucosal edema in the absence of urticaria due to the accumulation of bradykinin. This descriptive study aimed to evaluate the clinical characteristics of patients with a confirmed diagnosis of HAE referred to our Outpatient Clinic between December 2009 and November 2017. Fifty-one patients (38 F, 13 M) with a mean age of 32 years (range: 7–70 y) were included. Family history of HAE was reported in 70% (36/51) of the cases; 33/46 patients became symptomatic by 18 years of age. The median time between onset of symptoms and diagnosis was 13 years (3 mo–50 y). The most frequent triggering factors for attacks were stress (74.4%), trauma (56.4%), and hormonal variations (56%). The main symptoms were subcutaneous edema in 93.5% (43/46) of patients, gastrointestinal symptoms in 84.8% (39/46), and obstruction in the upper airways in 34.8% (16/46). Hospitalization occurred in 65.2%, of whom 13.3% had to be transferred to the Intensive Care Unit. Prophylactic treatment was instituted in 87% (40/46) of patients, and 56.5% (26/46) required additional treatment to control attacks. Owing to our data collection over a period of 8 years, a significant number of patients were identified by this HAE reference center. Despite early recognition and prophylactic treatment, a high percentage of patients were hospitalized. HAE is still diagnosed late, reinforcing the need for more reference centers specialized in diagnosis and educational projects for health professionals.

Hereditary angioedema from the patient's perspective: A follow-up patient survey

BACKGROUND

We conducted our first patient survey at the 2013 hereditary angioedema (HAE) patient summit and learned that, despite several novel therapies, the burden of disease was high.

OBJECTIVE

To determine, from the patient's perspective, if any improvements in the current state of HAE care occurred over a two-year period between HAE patient summits.

METHODS

A patient survey was conducted at the 2015 Hereditary Angioedema Association conference by using paper surveys that aimed at understanding the current state of HAE care. Questions included patient characteristics, burden of disease, and satisfaction with care and treatment options. Comparisons between patients with HAE with C1-inhibitor (HAE-C1INH) and patients with HAE with normal C1-inhibitor (HAE-nlC1INH), as well as between patients with HAE in 2013 and 2015, were performed by using χ2 tests.

RESULTS

There were 232 surveys distributed, and 143 surveys were identified as complete for inclusion and analysis from patients with self-reported HAE. Most patients had type I or type II HAE (67.5% [n = 106]), with a smaller number of patients with HAE-nlC1INH (23.6% [n = 37]). In 2015, almost half of the patients with HAE-C1INH (47.1%) and 56.7% of the patients with HAE-nlC1INH experienced a delay of ≥10 years between initial symptoms and diagnosis. Among the patients with HAE-C1INH, 25% reported one or more attacks per week and another 48% reported experiencing one or more attacks per month (fewer than one attack per week). The patients with HAE-nlC1INH reported attacks more frequently than did the patients with HAE-C1INH (p = 0.002), with 59.5% who reported attacks at least once a week. Emergency care was reported one or more times per month in 5% of the patients with HAE-C1INH and in 24.3% of the patients with HAE-nlC1INH.

CONCLUSION

Similar to 2013, although significant progress has been made, there is still a high burden of disease that faces patients with HAE.

Clinical Features of Hereditary Angioedema in Korean Patients: A Nationwide Multicenter Study

BACKGROUND

Hereditary angioedema (HAE) is a genetically heterogeneous autosomal dominant disorder characterized by recurrent episodes of nonpruritic, nonpitting edema increasing after puberty. It can be fatal due to laryngeal or gastrointestinal (GI) involvement with varied and changing frequency of mortality according to studies published from the Western countries. Epidemiological and clinical data of HAE in Asian countries are sparse. We sought to examine the clinical characteristics of HAE patients in Korea.

METHODS

Patients diagnosed with HAE at 15 tertiary hospitals across the country until 2016 were retrospectively reviewed.

RESULTS

A total of 65 patients diagnosed with HAE by 2016 were identified. The prevalence of HAE was estimated at 1.3/1,000,000 in Korea. Of the 65 patients, 21 (32.3%) were males. A total of 90.8% patients had type I HAE, while the remaining 9.2% patients had type II HAE. The first symptom developed after 20 years in 73.8% of patients, with a mean age 28.4 ± 14.1 years. The age at diagnosis was 36.5 ± 15.8 years, with a mean time delay of 7.8 ± 10.5 years. While the face (82.3%) and extremities (upper 71.0%, lower 62.9%) were the most frequently involved, the GI tract was affected in 40.5% of Korean HAE patients. Prophylaxis was maintained in 62.5% of patients. There was no reported case of death from HAE so far.

CONCLUSIONS

The clinical manifestation and severity of HAE may vary according to ethnicity. HAE is more infrequent and GI involvement is less likely in Korea compared with Western countries.

Brazilian Guidelines for Hereditary Angioedema Management - 2017 Update Part 1: Definition, Classification and Diagnosis

Hereditary angioedema is an autosomal dominant disease characterized by recurrent angioedema attacks with the involvement of multiple organs. The disease is unknown to many health professionals and is therefore underdiagnosed. Patients who are not adequately diagnosed and treated have an estimated mortality rate ranging from 25% to 40% due to asphyxiation by laryngeal angioedema. Intestinal angioedema is another important and incapacitating presentation that may be the main or only manifestation during an attack. In this article, a group of experts from the "Associação Brasileira de Alergia e Imunologia (ASBAI)" and the "Grupo de Estudos Brasileiro em Angioedema Hereditário (GEBRAEH)" has updated the Brazilian guidelines for the diagnosis and treatment of hereditary angioedema.

Misdiagnosis trends in patients with hereditary angioedema from the real-world clinical setting

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) causes swelling in the skin and upper airways and pain in the abdomen because of mucosal swelling. C1-INH-HAE is frequently misdiagnosed, leading to delays in diagnosis, inadequate treatment, and unnecessary procedures.

OBJECTIVE

To evaluate the history of misdiagnosis in patients participating in the Icatibant Outcome Survey (IOS).

METHODS

The IOS is an observational study in which safety and effectiveness of icatibant have been evaluated since 2009. As part of the IOS, patients record any misdiagnoses received before being diagnosed as having C1-INH-HAE.

RESULTS

In January 2016, a total of 418 of 633 IOS patients with C1-INH-HAE type I or II had provided misdiagnosis data. Of these, 185 of 418 (44.3%) received 1 or more prior misdiagnoses. The most common misdiagnoses were allergic angioedema (103 of 185) and appendicitis (50 of 185). A variety of other misdiagnoses were reported, including a substantial number of gastrointestinal disorders (excluding appendicitis). Misdiagnosis rates were similar between males (41.1%) and females (46.5%) and between C1-INH-HAE type I (43.7%) and type II (51.6%). Patients with family members diagnosed as having C1-INH-HAE were significantly less likely to be misdiagnosed than patients without a family history (140 of 366 [41.7%] vs 38 of 58 [65.5%], respectively; P = .001). Patients with a prior misdiagnosis had longer median delay to C1-INH-HAE diagnosis (13.3 years) than patients without (1.7 years; P < .001).

CONCLUSION

From this large database, approximately 50% of patients with C1-INH-HAE type I or II have previously had their conditions misdiagnosed, most commonly as allergic angioedema or appendicitis. Misdiagnosis results in marked delays in receiving the correct diagnosis, during which time patients cannot access effective, lifesaving treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01034969.

Screening for hereditary angioedema (HAE) at 13 emergency centers in Osaka, Japan: A prospective observational study

Hereditary angioedema (HAE) with deficiency of C1 inhibitor (C1-INH) is an autosomal-dominant disease characterized by recurrent episodes of potentially life-threatening angioedema. The objective is to study the incidence of HAE among patients who visit the emergency department.This was a 3-year prospective observational screening study involving 13 urban tertiary emergency centers in Osaka prefecture, Japan. Patients were included if they met the following criteria: unexplained edema of the body, upper airway obstruction accompanied by edema, anaphylaxis, acute abdomen with intestinal edema (including ileus and acute pancreatitis), or asthma attack. C1-INH activity and C4 level were measured at the time of emergency department admission during the period between July 2011 and June 2014.This study comprised 66 patients with a median age of 54.0 (IQR: 37.5-68.3) years. Three patients were newly diagnosed as having HAE, and 1 patient had already been diagnosed as having HAE. C1-INH activity levels of the patients with HAE were below the detection limit (<25%), whereas those of non-HAE patients (n = 62) were 106% (IQR: 85.5%-127.0%) (normal range, 70%-130%). The median level of C4 was significantly lower in the patients with HAE compared with those without HAE (1.2 [IQR: 1-3] mg/dL vs 22 [IQR: 16.5-29.5] mg/dL, P < 0.01) (normal range, 17-45 mg/dL).Three patients with undiagnosed HAE were diagnosed as having HAE in the emergency department during the 3-year period. If patients have signs and symptoms suspicious of HAE, the levels of C1-INH activity and C4 should be measured.

Management of Children With Hereditary Angioedema Due to C1 Inhibitor Deficiency

Hereditary angioedema (HAE) is a potentially life-threatening inherited disease characterized by attacks of skin swelling, severe abdominal pain, and upper airway swelling. Attacks typically begin in childhood, but the appropriate diagnosis is often missed. Attacks do not respond to epinephrine, antihistamines, or glucocorticoids. Recently, many effective drugs have been approved for treatment of adults with HAE, and the Medical Advisory Board of the HAE Patient's Association has developed and reported treatment recommendations for adults. Only 1 medication is approved for treatment of children <12 years of age, and there are no reported consensus recommendations for treatment of young children in the United States. The 11-member Medical Advisory Board, with extensive experience in the treatment of children, in concert with the leaders of the HAE Patient's Association, has developed these consensus recommendations to help in recognition, diagnosis, treatment of attacks, and prophylaxis of children with HAE.

Frequent life-threatening laryngeal attacks in two Croatian families with hereditary angioedema due to C1 inhibitor deficiency harbouring a novel frameshift mutation in SERPING1

OBJECTIVE

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare autosomal dominant disease caused by mutations in the SERPING1 gene. It can affect many regions in the body, but potentially life-threatening laryngeal oedemas are of concern.

METHODS

Twenty-three subjects from two families were recruited for clinical data evaluation and molecular analysis at General Hospital Šibenik, Croatia.

RESULTS

Decreased levels of C1 inhibitor were detected in 12 adult patients and three young asymptomatic persons. The same novel deletion of two nucleotides on exon 3 (c.74_75delAT) was identified in all of them. A history of laryngeal oedema was present in 10 patients (83%), and all patients reported laryngeal attacks at least once a year. The delay in diagnosis decreased noticeably from the first to the last generation.

CONCLUSIONS

We identified a novel causative mutation in SERPING1 in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema. Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype-phenotype relationship. Key messages Hereditary angioedema due to C1 inhibitor deficiency is a rare autosomal dominant disease caused by mutations in the SERPING1 gene, and laryngeal oedema is of concern because it can cause death by asphyxiation. A novel causative mutation in SERPING1, a deletion of two nucleotides on exon 3 (c.74_75delAT), was identified in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema. Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype-phenotype relationship because it appears that the mutation type may affect disease severity.

Expert perspectives on hereditary angioedema: Key areas for advancements in care across the patient journey

BACKGROUND

Published literature documents the substantial burden of hereditary angioedema (HAE) with C1 inhibitor deficiency on the quality of life and work productivity of patients. However, despite advances in the field and the availability of guidelines to advise health care providers (HCP) on the diagnosis and management of HAE, there are still many challenges to overcome. For example, delayed diagnosis and misdiagnosis are common, and treatment practices vary worldwide.

OBJECTIVE

An international expert panel was convened to consider opportunities for improvements that would benefit patients with HAE.

METHODS

Based on professional and personal experiences, the experts developed schematics to describe the journey of patients through the following stages: (1) onset of symptoms and initial evaluation; (2) referral/diagnosis; and (3) management of HAE. More importantly, the panel identified key areas in which it was possible to optimize the support provided to patients and HCPs along this journey.

RESULTS

Overall, this approach highlighted the need for wider dissemination of algorithms and scientific data to more effectively educate HCPs from multiple disciplines and the need for more research to inform appropriate treatment decisions. Furthermore, HAE awareness campaigns, accurate online information, and referral to patient advocacy groups were all considered helpful approaches to support patients.

CONCLUSION

More detailed and widespread information on the diagnosis and management of HAE is needed and may lead to advancements in care throughout the journey of the patient with HAE.

Diagnosis and screening of patients with hereditary angioedema in primary care

Hereditary angioedema (HAE) is a rare autosomal dominant disease that commonly manifests with episodes of cutaneous or submucosal angioedema and intense abdominal pain. The condition usually presents due to a deficiency of C1 esterase inhibitor (C1-INH) that leads to the overproduction of bradykinin, causing an abrupt increase in vascular permeability. A less-understood and less-common form of the disease presents with normal C1-INH levels. Symptoms of angioedema may be confused initially with mast cell-mediated angioedema, such as allergic reactions, and may perplex physicians when epinephrine, antihistamine, or glucocorticoid therapies do not provide relief. Similarly, abdominal attacks may lead to unnecessary surgeries or opiate dependence. All affected individuals are at risk for a life-threatening episode of laryngeal angioedema, which continues to be a source of fatalities due to asphyxiation. Unfortunately, the diagnosis is delayed on average by almost a decade due to a misunderstanding of symptoms and general lack of awareness of the disease. Once physicians suspect HAE, however, diagnostic methods are reliable and available at most laboratories, and include testing for C4, C1-INH protein, and C1-INH functional levels. In patients with HAE, management consists of acute treatment of an attack as well as possible short- or long-term prophylaxis. Plasma-derived C1-INH, ecallantide, icatibant, and recombinant human C1-INH are new treatments that have been shown to be safe and effective in the treatment of HAE attacks. The current understanding of HAE has greatly improved in recent decades, leading to growing awareness, new treatments, improved management strategies, and better outcomes for patients.

Managing the female patient with hereditary angioedema

Hereditary angioedema (HAE) is a rare disorder resulting from decreased functional levels of C1-inhibitor (C1-INH), which manifests as periodic episodes of localized edema which can be extremely painful, debilitating and even fatal if the swelling affects the larynx. HAE can complicate many aspects of obstetric/gynecologic care, and an awareness of the disease is critical for clinicians involved in the care of women because of potential HAE-related complications pertaining to pregnancy, labor and delivery, and other women's health issues. This article provides a review of published literature specific to HAE and its management in female patients, including important concerns regarding obstetric/gynecologic care. A growing body of relevant experience is presented to help guide the care of women with HAE.

Prevalence of hereditary angioedema in untested first-degree blood relatives of known subjects with hereditary angioedema

Hereditary angioedema (HAE) is a rare autosomal-dominant disease characterized by recurring attacks of nonpruritic, nonpitting edema caused by an inherited deficiency or dysfunction of C1 esterase inhibitor (C1 INH). Symptoms can present years before an accurate diagnosis is made. The objective of this study, the Angioedema Clinical Epidemiology Testing Initiative for the Study of Hereditary Angioedema, was to determine the prevalence and clinical manifestations of HAE in untested first-degree blood relatives of known patients with HAE. Patients with a confirmed diagnosis of HAE recruited first-degree relatives who had not been evaluated for HAE. Enrolled subjects underwent complement testing (C4, C1 INH antigen, and functional C1 INH). If the lab tests were abnormal, the enrolled subjects returned to the site for a follow-up visit and questionnaire. Overall, 31 patients with HAE and 46 first-degree relatives enrolled in the study. Of 46 enrolled relatives, 30 (65%) had lab test results that ruled out a diagnosis of HAE, two (4%) were categorized as "HAE not ruled out," and 14 (30%) were newly diagnosed with HAE. Of 14 newly diagnosed subjects, nine (64%) reported having experienced symptoms that may have been related to HAE, such as swelling in the throat, face, or extremities or abdominal pain. When reported, median age of symptom onset in these 14 subjects was nine years whereas newly diagnosed asymptomatic subjects had a median chronological age of six years. These 14 subjects reported a historic mean standard deviation rate of 2.51 (5.59) swelling episodes per month with a mean standard deviation duration of 1.6 (0.74) days. This study's findings reinforce the importance of testing family members of patients with HAE to detect this hereditary condition.

Current state of hereditary angioedema management: a patient survey

Hereditary angioedema (HAE) is a chronic disease with a high burden of disease that is poorly understood and often misdiagnosed. Availability of treatments, including C1 esterase inhibitor (C1INH) replacement, ecallantide, and icatibant, marks a significant advance for HAE patients. We aimed to better understand the current state of HAE care, from a patient perspective, after the introduction of several novel therapies. One session of the United States Hereditary Angioedema Association 2013 patient summit was devoted to data collection for this study. Patients attending the summit were self-selected, and HAE diagnosis was self-reported. Survey questions assessed patient characteristics, burden of disease, and treatment. Participant responses were captured using an audience response system. We surveyed 149 (80%) type I and II HAE (HAE-C1INH) and 37 (20%) HAE with normal C1INH (HAE-nlC1INH) patients. HAE-C1INH (72%) and HAE-nlCINH patients (76%) equally reported that HAE had a significant impact on quality of life (QOL). A third of HAE-C1INH patients were diagnosed within one year of their first HAE attack, but another third reported a delay of more than 10 years. Most HAE-C1INH (88%) and HAE-nlC1INH (76%) patients had on-demand treatment available. HAE-C1INH patients frequently had an individual treatment plan (76%) compared with 50% of HAE-nlC1INH patients. Most HAE-C1INH patients went to the emergency department (ED) or were hospitalized less than once every six months (80%). Our findings show that HAE management is improving with good access to on-demand and prophylactic treatment options. However, HAE patients still have a significant burden of disease and continued research and educational efforts are needed.

Clinical manifestations, diagnosis, and treatment of hereditary angioedema: survey data from 94 physicians in Japan

BACKGROUND

Hereditary angioedema (HAE) is a rare and potentially life-threatening condition that results from mutations in the C1 inhibitor (C1-INH). Awareness of HAE among physicians in Japan is increasing, but real-world data are lacking.

OBJECTIVE

To explore the clinical manifestations, diagnosis, quality of life (QOL), and treatment of Japanese patients with HAE.

METHODS

A 14-point survey was developed and sent to 387 physicians in Japan (March to May 2014) to gather clinical data on their HAE patients' family history, severity and frequency of attacks, QOL, and therapy use.

RESULTS

Data on 171 HAE patients were collected from 94 physicians (24.3% response rate). Of the patients, 76.6% had a family history of angioedema (AE), and 11.7% had experienced a death in the family due to an AE attack. HAE type I occurred in 99 patients (57.9%), HAE type II occurred in 9 patients (5.3%), HAE with normal C1-INH occurred in 3 patients (1.8%), and an additional 60 patients were unclassified. Mean time from initial symptoms to diagnosis was 13.8 years. Attacks that required airway management and abdominal surgery with uncertain diagnosis were observed in 9.5% and 2.9% of patients, respectively. In the past year, 21.0% of patients presented with more than 10 attacks, 21.1% were admitted to the hospital for more than 1 day, and 28.7% were absent from work or school. On-demand C1-INH concentrate and prophylactic tranexamic acid were used in approximately half of the patients (47.4% and 39.2%, respectively).

CONCLUSION

HAE is a severe condition characterized by recurrent AE attacks. In Japan, delayed patient diagnosis and limited use of HAE-specific therapies exacerbate the burden on HAE patients.

Hereditary angioedema: what the gastroenterologist needs to know

Up to 93% of patients with hereditary angioedema (HAE) experience recurrent abdominal pain. Many of these patients, who often present to emergency departments, primary care physicians, general surgeons, or gastroenterologists, are misdiagnosed for years and undergo unnecessary testing and surgical procedures. Making the diagnosis of HAE can be challenging because symptoms and attack locations are often inconsistent from one episode to the next. Abdominal attacks are common and can occur without other attack locations. An early, accurate diagnosis is central to managing HAE. Unexplained abdominal pain, particularly when accompanied by swelling of the face and extremities, suggests the diagnosis of HAE. A family history and radiologic imaging demonstrating edematous bowel also support an HAE diagnosis. Once HAE is suspected, C4 and C1 esterase inhibitor (C1-INH) laboratory studies are usually diagnostic. Patients with HAE may benefit from recently approved specific treatments, including plasma-derived C1-INH or recombinant C1-INH, a bradykinin B2-receptor antagonist, or a kallikrein inhibitor as first-line therapy and solvent/detergent-treated or fresh frozen plasma as second-line therapy for acute episodes. Short-term or long-term prophylaxis with nanofiltered C1-INH or attenuated androgens will prevent or reduce the frequency and severity of episodes. Gastroenterologists can play a critical role in identifying and treating patients with HAE, and should have a high index of suspicion when encountering patients with recurrent, unexplained bouts of abdominal pain. Given the high rate of abdominal attacks in HAE, it is important for gastroenterologists to appropriately diagnose and promptly recognize and treat HAE, or refer patients with HAE to an allergist.

Comparison of chromogenic and ELISA functional C1 inhibitor tests in diagnosing hereditary angioedema

INTRODUCTION

Measuring functional C1 inhibitor (C1 INH) with chromogenic or ELISA methods can confirm a diagnosis of hereditary angioedema (HAE) due to C1 INH deficiency. Previous studies found differences in the agreement of these assays.

OBJECTIVE

To evaluate the agreement between chromogenic or ELISA methods in the context of an observational study.

METHODS

Patients with previously confirmed HAE underwent functional C1 INH testing. These patients contacted first-degree relatives (parents, siblings, or offspring) not previously evaluated for HAE, who underwent a panel of complement testing, including for functional C1 INH.

RESULTS

Overall, 31 patients with HAE and 46 untested relatives enrolled. Of 46 relatives, 14 (30.4%) were newly diagnosed with HAE based on their laboratory results. Among the 31 patients previously confirmed with HAE, all had low functional C1 INH according to the chromogenic method, whereas 22 (71.0%) had low, 7 (22.6%) had equivocal, and 2 (6.5%) had normal functional C1 INH according to the ELISA method. In the 14 newly diagnosed relatives, all had low functional C1 INH according to the chromogenic method, whereas 11 (78.5%) had low and 3 (21.4%) had equivocal results according to the ELISA method.

CONCLUSION

Despite the apparent discordance in the ELISA and chromogenic assays in a small number of patients, both were useful in measuring functional C1 INH. To establish the diagnosis of HAE due to C1 INH deficiency, functional C1 INH results should be interpreted in combination with family and clinical history, and with other complement tests.

Treatment of hereditary angioedema: a review (CME)

Hereditary angioedema (HAE) is a rare autosomal dominant disorder characterized by recurrent attacks of self-limiting tissue swelling. The management of HAE has transformed dramatically with recently approved therapies in the United States. However, there is lack of awareness among physicians about these new modalities. The aim of this review is to update the practicing physician about various therapeutic options available for HAE patients. An exhaustive literature search of PubMed and OVID was performed to develop this article. Management of HAE is traditionally classified into treatment of acute attacks or on-demand therapy, short-term (preprocedural) prophylaxis, and long-term prophylaxis. Newer therapies include C1 esterase inhibitor (C1-INH) and contact system modulators, namely, ecallantide and icatibant. Recombinant C1-INH, which is available in Europe, is awaiting approval in the United States. C1-INH concentrate is approved for prophylaxis as well as on-demand therapy while ecallantide and icatibant are approved for acute treatment only. Effective HAE management further includes patient education, reliable access to specific medications, and regular follow-up to monitor therapeutic response and safety.

A consensus parameter for the evaluation and management of angioedema in the emergency department

Despite its relatively common occurrence and life-threatening potential, the management of angioedema in the emergency department (ED) is lacking in terms of a structured approach. It is paramount to distinguish the different etiologies of angioedema from one another and more specifically differentiate histaminergic-mediated angioedema from bradykinin-mediated angioedema, especially in lieu of the more novel treatments that have recently become available for bradykinin-mediated angioedema. With this background in mind, this consensus parameter for the evaluation and management of angioedema attempts to provide a working framework for emergency physicians (EPs) in approaching the patient with angioedema in terms of diagnosis and management in the ED. This consensus parameter was developed from a collaborative effort among a group of EPs and leading allergists with expertise in angioedema. After rigorous debate, review of the literature, and expert opinion, the following consensus guideline document was created. The document has been endorsed by the American College of Allergy, Asthma & Immunology (ACAAI) and the Society for Academic Emergency Medicine (SAEM).

Hereditary angioedema with C1 inhibitor deficiency: delay in diagnosis in Europe

BACKGROUND

Hereditary angioedema (HAE) is a rare, debilitating, and potentially life-threatening disease characterized by recurrent edema attacks. Important advances in HAE treatment have been made, including the development of new therapies for treating or preventing attacks. Nevertheless, the disease is still frequently misdiagnosed and inappropriately treated, potentially exposing patients with laryngeal attacks to the risk of asphyxiation.

METHODS

The Icatibant Outcome Survey (IOS) is an international, observational study that documents the clinical outcome of HAE patients eligible for treatment with icatibant. Patient ages at first symptoms and at diagnosis were recorded at enrolment, and the delay between first symptoms and diagnosis was calculated.

RESULTS

The median [range] diagnostic delay in HAE type I and II patients across eight countries was 8.5 years [0-62.0]. The median delay in diagnosis was longer for HAE type II versus type I (21 versus 8 years, respectively), although this did not quite reach statistical significance.

CONCLUSIONS

Although it can be difficult to differentiate HAE symptoms from those of more common angioedema sub-types (e.g. idiopathic or acquired angioedema), our results show that HAE type I and II patients have an unacceptable delay in diagnosis, even those with a family history of the disease. Raising physician awareness of this disabling and potentially fatal disease may lead to a more accurate diagnosis and timely treatment.

Depression and anxiety in patients with hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is characterized by edematous swelling attacks of the face, extremities, abdomen, genitalia, and upper airway. The potential for laryngeal swelling makes the disease life-threatening, and the swelling elsewhere contributes to the significant burden of illness. The increased risk for mental health disorders in HAE is due to the burden of disease and possibly associated activation of the immune system.

OBJECTIVE

To determine the prevalence of depression and anxiety in HAE patients and the most high-yield features of depression to target in a clinical encounter.

METHODS

Depression and anxiety symptoms were evaluated using the 29 items of the Hamilton Depression Rating Scale along with the 14-item Hamilton Anxiety Rating Scale. The sample size was 26 participants with a diagnosis of type 1 or 2 HAE drawn from a cohort of 60 adult patients. In addition, a literature search was performed regarding how immune modulation affects depression and anxiety.

RESULTS

A total of 39% of participants were identified as experiencing depression of mild (50%), moderate (40%), or severe (10%) levels. Fifteen percent of participants displayed prominent anxiety, half of whom had mild anxiety, 25% moderate anxiety, and 25% severe anxiety. The literature on inflammation and depression suggests a possible link between HAE and depression.

CONCLUSION

Our data and the literature support that depression and anxiety symptoms are common in patients with HAE and may be secondary to chronic disease burden, associated pathophysiologic features, or both. Treatment that addresses the psychosocial and mental health of HAE patients is critical for best practice.

Current status of implementation of self-administration training in various regions of Europe, Canada and the USA in the management of hereditary angioedema

Results from a 16-question survey about self-administration of hereditary angioedema (HAE) therapy, administered in Europe, Canada and the USA, were used to guide discussion at an international HAE expert meeting. The aim was to capture information about current practice in self-administered HAE therapy in these countries, including self-administration training, the key benefits of switching to self-administration, the barriers to self-administration and trends in self-administration. Overall, switching to self-administration therapy is looked upon favourably from both patient and clinician perspectives by virtue of the potential improvement in quality of life arising from optimisation of therapy and early intervention. The recent changes to product licences allowing self-administration provide additional options for the management of HAE.

Hereditary angioedema caused by c1-esterase inhibitor deficiency: a literature-based analysis and clinical commentary on prophylaxis treatment strategies

Hereditary angioedema (HAE) caused by C1-esterase inhibitor deficiency is an autosomal-dominant disease resulting from a mutation in the C1-inhibitor gene. HAE is characterized by recurrent attacks of intense, massive, localized subcutaneous edema involving the extremities, genitalia, face, or trunk, or submucosal edema of upper airway or bowels. These symptoms may be disabling, have a dramatic impact on quality of life, and can be life-threatening when affecting the upper airways. Because the manifestations and severity of HAE are highly variable and unpredictable, patients need individualized care to reduce the burden of HAE on daily life. Although effective therapy for the treatment of HAE attacks has been available in many countries for more than 30 years, until recently, there were no agents approved in the United States to treat HAE acutely. Therefore, prophylactic therapy is an integral part of HAE treatment in the United States and for selected patients worldwide. Routine long-term prophylaxis with either attenuated androgens or C1-esterase inhibitor has been shown to reduce the frequency and severity of HAE attacks. Therapy with attenuated androgens, a mainstay of treatment in the past, has been marked by concern about potential adverse effects. C1-esterase inhibitor works directly on the complement and contact plasma cascades to reduce bradykinin release, which is the primary pathologic mechanism in HAE. Different approaches to long-term prophylactic therapy can be used to successfully manage HAE when tailored to meet the needs of the individual patient.

Challenges of C1-Inhibitor Concentrate Self-Administration

Self-administration of therapy can help hereditary angioedema (HAE) patients regain control of their disease or reduce its impact and improve the quality of their lives. However, data from a self-administration survey, and subsequent discussion at an international HAE expert meeting, identified several barriers to self-administration therapy. These barriers include difficulty in administration technique, availability of nursing resources and the mental capacity of the patient. Encouragingly, international HAE experts identified that once a patient has acquired self-administration skills, they generally retain them in the long-term. As patient uptake increases, it was recommended that follow-up management plans should be established to address any issues from the patient's perspective.