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Hereditary angioedema (HAE) is a rare genetic condition causing unpredictable and severe episodes of angioedema that are debilitating and life-threatening. Moreover, HAE can be classified into HAE due to C1-esterase inhibitor deficiency (HAE-C1INH) or HAE with normal C1INH. Moreover, HAE-C1INH is subcategorized as types I and II based on deficient or dysfunctional circulating C1INH protein resulting from inherited or spontaneous mutations in the SERPING1 gene leading to uncontrolled factor XII/plasma kallikrein activation and excessive bradykinin production. Bradykinin-2 receptor activation leads to vasodilation, increased vascular permeability, and smooth muscle contractions, resulting in subcutaneous or submucosal fluid extravasation that can affect the face, extremities, airway, and gastrointestinal and genitourinary systems. Furthermore, HAE with normal C1INH is caused by either a known or unknown genetic mutation, and the mechanisms are less well-established but most forms are thought to be related to bradykinin signaling with a similar presentation as HAE-C1INH despite normal levels of C1INH protein and function. Current HAE management strategies include on-demand and prophylactic treatments which replace C1INH, reduce kallikrein activity, or block bradykinin binding to the bradykinin B2 receptor. With the advent of additional small molecule inhibitors, monoclonal antibodies, RNA-targeted therapies, gene therapies, and gene modification approaches, preclinical studies and human clinical trials are underway to further expand therapeutic options in HAE. This review article will briefly summarize current HAE treatments and provide an overview of potential future therapies for HAE., Competing Interests: Disclosures Dr Riedl has received research support from BioCryst, BioMarin, CSL Behring, Ionis Pharmaceuticals, KalVista, Pharvaris, and Takeda and consultancy fees from Astria, BioCryst, BioMarin, CSL Behring, Cycle Pharma, Grifols, Intellia, KalVista, Ono Pharma, Pfizer, Pharming, Pharvaris, Sanofi-Regeneron, and Takeda. Dr Smith has no conflicts of interest to report., (Copyright © 2024 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Hereditary angioedema is a rare, genetic disorder characterized by painful, debilitating and potentially life-threatening angioedema attacks in subcutaneous and submucosal tissue. While usually unpredictable, attacks can be provoked by a variety of triggers including physical injury and certain medication and are often preceded by prodromal symptoms. Hereditary angioedema has a profound influence on the patients' lives. The fundamental cause of hereditary angioedema in almost all patients is a mutation in the SERPING1 gene leading to a deficiency in C1-inhibitor. Subsequently, the contact activation cascade and kallikrein-kinin pathway are insufficiently inhibited, resulting in excessive bradykinin production triggering vascular leakage. While C1-inhibitor is an important regulator of the intrinsic coagulation pathway, fibrinolytic system and complement cascade, patients do not have an increased risk of coagulopathy, autoimmune conditions or immunodeficiency disorders. Hereditary angioedema is diagnosed based on C1-inhibitor level and function. Genetic analysis is only required in rare cases where hereditary angioedema with normal C1-inhibitor is found. In recent years, new, highly specific therapies have greatly improved disease control and angioedema-related quality of life. This article reviews the clinical picture of hereditary angioedema, the underlying pathophysiology, diagnostic process and currently available as well as investigational therapeutic options., Competing Interests: D.M.C. reports personal fees from Biocryst, personal fees from CSL, personal fees from Ionis pharmaceuticals, personal fees from KalVista, personal fees from Pharvaris, outside the submitted work., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).)

Purpose: To describe a rare case of vision loss due to bilateral edema of the optic nerve in a patient with Hereditary Angioedema, treated with prophylactic C1-esterase inhibitor., Methods: A 60-year-old Caucasian male affected by Hereditary Angioedema with unknown genetic defect (HAE- UNK) was admitted to our hospital presenting bilateral vision loss (best corrected visual acuity of 20/32 in the right eye and hand motion in the left eye) during an HAE attack. Intravenous administration of C1- esterase inhibitor (C1-INH, 1500 IU, Berinert, CSL Behring) determined the resolution of facial and periorbital swelling, however visual impairment persisted, in contrast with previous attacks experienced by the patient. Fundus examination revealed a vital optic disc without papilledema in both eyes. Magnetic resonance imaging (MRI) of the head and orbits showed bilateral edema of the optic nerve sheath. Treatment with intravenous and oral steroids was ineffective. Subsequently, a prophylactic treatment strategy with subcutaneous C1-esterase inhibitor was started (7000 IU every four days)., Results: Complete regression of edema of the optic nerves was observed by imaging at two months of follow-up after chronic treatment with C1-esterase inhibitor (7000 IU every four days). Complete restoration of visual acuity was achieved (BCVA 20/20 in both eyes) and multimodal imaging of the optic nerves demonstrated the absence of anatomical and functional damage., Conclusion: Patients affected by HAE may show atypical presentation with edema of the optic nerves without involvement of the optic nerve head. They may significantly benefit from prophylactic and chronic treatment with C1-esterase inhibitor., Competing Interests: Consent for publicationWritten informed consent was obtained from the patient. Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder that usual results from a decreased level of functional C1-INH and clinically manifests with intermittent attacks of swelling of the subcutaneous tissue or submucosal layers of the respiratory or gastrointestinal tracts. Laboratory studies and radiographic imaging have limited roles in evaluation of patients with acute attacks of HAE except when the diagnosis is uncertain and other processes must be ruled out. Treatment begins with assessment of the airway to determine the need for immediate intervention. Emergency physicians should understand the pathophysiology of HAE to help guide management decisions., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Excessive bradykinin (BK) generation from high molecular weight kininogen (HK) by plasma kallikrein (PK) due to lack of protease inhibition is central to the pathophysiology of hereditary angioedema (HAE). Inadequate protease inhibition may contribute to HAE through a number of plasma proteases including factor VII activating protease (FSAP) that can also cleave HK., Objective: To investigate the interaction between FSAP and C1 inhibitor (C1Inh) and evaluate the potential role of FSAP in HAE with C1Inh deficiency., Materials and Methods: Plasma samples from 20 persons with HAE types 1 or 2 in remission were studied and compared to healthy controls. We measured and compared antigenic FSAP levels, spontaneous FSAP activity, FSAP generation potential, activation of plasma pre-kallikrein (PPK) by FSAP, and the formation of FSAP-C1Inh and FSAP-alpha2-antiplasmin (FSAP-α2AP) complexes. Furthermore, we measured HK cleavage and PK activation after activation of endogenous pro-FSAP and after addition of exogenous FSAP., Results: In plasma from HAE patients, there is increased basal FSAP activity compared to healthy volunteers. HAE plasma exhibits decreased formation of FSAP-C1Inh complexes and increased formation of FSAP-α2AP complexes in histone-activated plasma. Although exogenous FSAP can cleave HK in plasma, this was not seen when endogenous plasma pro-FSAP was activated with histones in either group. PK was also not activated by FSAP in plasma., Conclusion: In this study, we established that FSAP activity is increased and the pattern of FSAP-inhibitor complexes is altered in HAE patients. However, we did not find evidence suggesting that FSAP contributes directly to HAE attacks., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Hereditary angioedema (HAE) is a rare disease that manifests as recurrent and debilitating angioedema attacks, significantly impacting patients' quality of life., Objective: To assess communication dynamics between patients with HAE and treating physicians and the impact this has on the treatment of HAE in the United States., Methods: This observational study used an institutional review board-approved protocol to collect four sources of patient-physician communication data from the period between January 2015 and May 2017: in-office conversations between patients aged ≥18 years with HAE and physicians, follow-up dictations with physicians, telephone interviews with patients and physicians, and publicly available social media posts from patients. Participant language was qualitatively assessed and key communication elements and communication gaps identified., Results: Twenty-five in-office conversations, 14 follow-up physician dictations, and 17 telephone interviews were conducted with a total of 29 unique patients, 4 caregivers, and 14 physicians. In-office conversations were generally physician-driven and focused primarily on symptom frequency, location, and severity; lexicon from both parties centered on "episodes" and "swelling." During visits, impact on quality of life was not routinely assessed by physicians nor discussed proactively by patients; however, during telephone interviews and online, patients frequently described the multifaceted burden of HAE. Patients highlighted the difficulties they experience by using repetition, emphasis, and metaphors; they also varied the descriptors used for attacks depending on the communication goal. Physicians used intensifiers to emphasize the necessity of rescue medication access, whereas prophylactic treatments were positioned as an option for frequent or laryngeal attacks., Conclusion: Vocabulary differences suggest that the full impact of HAE is not consistently communicated by patients to physicians during clinical visits, indicating the potential for misaligned understanding of disease burden. A patient-driven, rather than physician-driven approach to the discussions may elicit valuable information that could help to optimize treatment approaches., Competing Interests: This research was funded by the sponsor, Shire, a Takeda company. Shire, a Takeda company, provided funding to Excel Medical Affairs for support in writing and editing this manuscript. The interpretation of the data was made by the authors independently. Gagan Jain is a full-time employee of Shire, a Takeda company, and holds stock/stock options in Takeda. Lauren Walter was a full-time employee of Verilogue at the time of this study, and is currently an employee of Real Chemistry. Carolyn Reed was a fulltime employee of Verilogue at the time of this study, and is currently an employee of Comcast. Patricia O’Donnell and Jeffrey Troy are full-time employees of Verilogue. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: The demonstration that severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) enters the cell via the angiotensin-converting enzyme 2 receptor has raised concerns that, in hereditary angioedema (HAE), a disease characterized by bradykinin-mediated angioedema attacks, coronavirus disease 2019 (COVID-19) may trigger angioedema attacks, increase the frequency and/or severity of attacks, or cause more severe symptoms of COVID-19. Objective: The objective was to evaluate the severity of COVID-19 in patients with HAE, the course of HAE attacks, angioedema activity, and the quality-of-life scores during COVID-19 pandemic. Methods: Patients diagnosed with HAE for at least 6 months were included in the study. The 7-day Angioedema Activity Score and the Angioedema Quality of Life (AE-QoL) Questionnaire were first completed at the onset of the pandemic between March 12 and June 1, 2020, then during SARS-CoV-2 infection, and in the third month after recovering from COVID-19. Results: Ten of 67 patients with HAE (14.9%) were diagnosed with COVID-19. The median (interquartile range) age of the 10 patients diagnosed with COVID-19 was 35.5 years (28.0-55.0 years). Six of the 10 patients (60%) were women. During COVID-19, five of the 10 patients (50%) had no angioedema attack. Two patients with severe HAE experienced a significant increase in angioedema activity during COVID-19 compared with their basal activity scores. The remaining three patients had a similar or lower attack frequency than their basal level. Four (40%) of the 10 patients had a relative increase in their attacks during the convalescence period. There was no statistically significant difference among pre-COVID-19, during COVID-19 and post-COVID-19 periods in function, mood, fear and/or shame, nutrition, and total scores of the AE-QoL Questionnaire although the fear dimension was relatively more affected (p = 0.06). Conclusion: Although the sample size was small, analysis of our data supported that the symptoms of COVID-19 were not more severe in HAE. Also, there was no significant difference in the AE-QoL Questionnaire scores, the frequency, and severity of angioedema attacks during the course of COVID-19 in the patients with HAE.

Hereditary Angioedema (HAE) is a rare genetic disease generally caused by deficiency or mutations in the C1-inhibitor gene, SERPING1, a member of the Serpin family. HAE results in acute attacks of edema, vasodilation, GI pain and hypotension. C1INH is a key inhibitor of enzymes controlling complement activation, fibrinolysis and the contact system. In HAE patients, contact system activation leads to uncontrolled production of bradykinin, the vasodilator responsible for the characteristic symptoms of HAE. In this study, we present the first physiological in vivo model to mimic acute HAE attacks. We evaluate hypotension, one of the many hallmark symptoms of acute HAE attacks using Serping1 deficient mice (serping1-/-) and implanted telemetry. Attacks were induced by IV injection of a silica nanoparticle (SiNP) suspension. Blood pressure was measured in real time, in conscious and untethered mice using implanted telemetry. SiNP injection induced a rapid, reversible decrease in blood pressure, in the presence of angiotensin converting enzyme (ACE) inhibition. We also demonstrate that an HAE therapeutic, ecallantide, can prevent HAE attacks in this model. The in vivo murine model described here can facilitate the understanding of acute HAE attacks, support drug development and ultimately contribute to improved patient care., (© 2021. The Author(s).)

Background: Hereditary angioedema (HAE) is associated with decreased quality of life (QoL), which has typically been measured using a generic non-disease-specific questionnaire., Objective: We aimed to assess the QoL in patients with HAE type I and II in Canada using a previously validated HAE-specific questionnaire., Methods: An online questionnaire was sent to the members of two Canadian HAE patient groups to collect data on demographics, HAE clinical course, and QoL scores. All patients 18 years of age or older with HAE type I or II were eligible. The impact of the available clinical factors on the QoL scores was evaluated. Multiple linear regression was performed using clinically relevant factors to predict HAE QoL outcome., Results: Among the 72 patients in the study, the mean total HAE QoL score was 102 (±23) (SD) on a scale of 25 to 135, with higher scores indicating better QoL. Although the total QoL scores correlated positively with patients' level of satisfaction and perceived control (P < .001 for both), it correlated negatively with the number of acute attacks (P = .03). Yet, the types of treatment did not have an impact on the QoL. Predictors, including sex, comorbidities, and the number of attacks, only explained 12% of the variance in the total QoL scores., Conclusion: HAE continues to impair QoL in Canadian patients despite receiving recommended treatment. Although the frequency of attacks affects QoL, patients' experience with their HAE care also affects QoL substantially. The study highlights the importance of considering patients' experience with their HAE care as physicians develop an appropriate management plan., (Copyright © 2021 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Hereditary angioedema is a rare disease that can often be disabling or even life threatening because of the unpredictable, self-limiting, and localized swelling episodes involving cutaneous, subcutaneous, and mucosal sites. The last decades revealed a spectrum of possibilities to control the disease through the development of effective therapies that changed the life of many patients and families worldwide. This review summarizes the current literature regarding the general management and therapeutic approach in patients with hereditary angioedema, both with and without C1 inhibitor deficiency. Medications already available in the market and new drugs in different research stages of development are addressed. Recent decades saw a huge leap in identifying mechanisms of angioedema and developing modern safe and effective medications to both treat acute angioedema manifestations and control disease activity via prophylactic therapy. Further improvement is still needed, together with improving global accessibility of diagnostic tools and effective medications. Whether novel drugs will demonstrate a sustained cost/effectiveness ratio will be answered in the years to come when we will witness whether a majority of the patients will benefit from these major advances.

This review aims to summarize the main pathophysiological events involved in the development of hereditary angioedema (OMIM#106100). Hereditary angioedema is a rare genetic disease inherited in an autosomal dominant manner and caused by a loss of control over the plasma contact system or kallikrein-kinin system, which results in unrestrained bradykinin generation or signaling. In patients with hereditary angioedema, BK binding to endothelial cells leads to recurrent episodes of swelling at subcutaneous or submucosal tissues that can be life threatening when affecting the upper respiratory tract. The disease can either present with hypocomplementemia owing to the presence of pathogenic variants in the gene encoding complement C1 inhibitor (hereditary angioedema with C1-inhibitor deficiency) or present with normocomplementemia and associate with elevated estrogen levels owing to gain-of-function variants in the genes encoding coagulation proteins involved in the kallikrein-kinin system (namely, coagulation FXII [FXII-associated hereditary angioedema], plasminogen [PLG-associated hereditary angioedema], and high-molecular-weight kininogen [KNG1-associated hereditary angioedema]). Moreover, in recent years, novel pathogenic variants have been described in the genes encoding angiopoietin 1 (ANGPT1-associated hereditary angioedema) and myoferlin (MYOF-associated hereditary angioedema), which further expand the pathophysiological picture of hereditary angioedema.

Angioedema without wheals (urticaria) represents a heterogeneous group of clinically indistinguishable diseases of hereditary or acquired etiology. Hereditary angioedema is a rare inherited condition leading to recurrent, sometimes life-threatening angioedema attacks in subcutaneous tissues and gastrointestinal and oropharyngeal mucosa dating back to childhood or adolescence. Most of these patients have mutations in the SERPING1 gene, causing either low C1 inhibitor production (hereditary angioedema with C1 inhibitor deficiency type I) or the production of dysfunctional C1 inhibitor (hereditary angioedema with C1 inhibitor deficiency type II). Hereditary angioedema with normal C1 inhibitor has been defined later. Although C1 inhibitor concentration and function are in the normal range, it leads to typical hereditary angioedema symptoms owing to mutations in FXII, PLG, ANGPT1, KNG1, and MYOF genes. Patients who exhibit none of these genetic mutations despite having a similar clinical presentation are classified as having unknown hereditary angioedema. Fewer than 1 in 10 patients with C1 inhibitor deficiency have acquired angioedema with C1 inhibitor deficiency. The clinical presentation is very similar to that of hereditary angioedema, making it difficult to distinguish these 2 conditions clinically. Unlike hereditary angioedema, there are no genetic mutations, and family history and symptoms tend to appear later in life. Acquired angioedema with C1 inhibitor deficiency is commonly associated with lymphoproliferative and autoimmune diseases. Angioedema attacks might start 1 year before the underlying disease in acquired angioedema with C1 inhibitor deficiency. Approximately half of the patients admitted to the hospital for acute angioedema are patients receiving angiotensin-converting enzyme (ACE) inhibitor therapy. Angioedema typically occurs on the lips, tongue, mouth, pharynx, and subglottic regions. Patients may require hospitalization and intensive care monitoring owing to airway involvement. Idiopathic histaminergic acquired angioedema may be diagnosed only when any possible causes of histaminergic angioedema are excluded (foods, drugs, animal dander, aeroallergens, insect stings, latex, and others), and the symptoms respond well to antihistamine treatment. Idiopathic nonhistaminergic acquired angioedema should be considered when all other types of recurrent angioedema have been ruled out and patients do not respond to high-dose antihistamines. The lack of a standard biochemical laboratory test for patients with idiopathic histaminergic acquired angioedema, idiopathic nonhistaminergic acquired angioedema, angiotensin-converting enzyme inhibitor-induced acquired angioedema, and hereditary angioedema with normal C1 inhibitor makes the diagnosis more challenging. Future efforts should focus on increasing awareness of all the rare types of angioedema among physicians and developing more straightforward and more accessible diagnostic methods.

The pathophysiology of hereditary angioedema (HAE) in virtually all cases is the result of the uncontrolled production of the vasoactive peptide bradykinin. C1 inhibitor (C1-INH) is a serine protease inhibitor, which, under normal circumstances, is the regulator of critical enzymes that are active in the cascades that result in bradykinin generation. In the classic forms of HAE, C1-INH is not produced in sufficient quantities (<40% of normal) or the function is <40% of normal activity. The major pathway for the production of bradykinin is the "contact system," also known as the kallikrein-kinin system. This system begins with the activation of factor XII (FXII) to FXIIa, by a variety of physiologic and pathologic stimuli. FXIIa is a serine protease that binds to surfaces and cleaves prekallikrein to the active serine protease kallikrein. Kallikrein then cleaves high-molecular-weight kininogen to release the nonapeptide bradykinin. Bradykinin binds to the bradykinin β2 receptor, which increases vascular permeability and allows the flow of fluids into the extracellular space and results in angioedema. The two major enzymes generated in this cascade FXIIa and kallikrein are inhibited by C1-INH, which is the major regulator of this cascade. Failure to adequately control the production of bradykinin is thus the major mechanism for HAE. Several other types of HAE in which C1-INH is not decreased (HAE nlC1-INH) have been described. The alterations in FXII and plasminogen (also a serine protease inhibited by C1-INH) like with classic HAE are the result of dysregulation of bradykinin generation. Only genetic alterations in angiopoietin-1 may not be related to bradykinin generation, rather related to the control of the effect of bradykinin on the vascular endothelium.

Hereditary angioedema (HAE) is a rare, autosomal dominant disease caused by a deficiency in the C1-inhibitor protein. It is characterized by recurrent episodes of nonpruritic, nonpitting, subcutaneous or submucosal edema that typically involves the extremities or the gastrointestinal tract. However, the genitourinary tract, face, oropharynx, and/or larynx may be affected as well. Symptoms often begin in childhood, worsen at puberty, and persist throughout life, with unpredictable severity. Patients who are untreated may have frequent attacks, with intervals that can range from every few days to rare episodes. Minor trauma and stress are frequent precipitants of swelling episodes, but many attacks occur without clear triggers. HAE attacks may be preceded by a prodrome and/or be accompanied by erythema marginatum. The swelling typically worsens over the first 24 hours, before gradually subsiding over the subsequent 48 to 72 hours. Although oropharyngeal swelling is less frequent, more than half of patients have had at least one episode of laryngeal angioedema during their lifetime. Attacks may start in one location and spread to another before resolving. HAE attacks that involve the abdomen or oropharynx have been associated with significant morbidity and mortality. Abdominal attacks can cause severe abdominal pain, nausea, and vomiting. Bowel sounds are often diminished or silent, and guarding and rebound tenderness may be present on physical examination. These findings may lead to unnecessary abdominal imaging and procedures. Fluid shifts into the interstitial space or peritoneal cavity can cause clinically significant hypotension. Laryngeal edema poses the greatest risk for patients with HAE. Although prompt diagnosis and treatment improves outcomes, the variable presentation of HAE can make it difficult to diagnose.

We herein report a 56-year-old Japanese woman who had been diagnosed with hereditary angioedema. She experienced progressing muscle weakness and pain in the upper and lower extremities. Blood tests revealed a marked increase in creatine kinase levels; however, myositis-specific autoantibodies were not detected. Serum C1-inhibitor activity and C4 levels were low. A muscle biopsy showed mild muscle fiber necrosis and C5b-9 deposition in the endomysial capillary vessel walls and sarcolemma, mimicking necrotizing myopathy. These results suggest that C1-inhibitor deficiency induces myositis-like symptoms through the activation of the complement pathway and deposition of the membrane attack complex in the muscles.

Background: Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurrent episodes of subcutaneous/submucosal edema, which may be preceded by erythema marginatum (EM) as a prodromal symptom. Our aim was to analyze the changes occurring in the parameters of the coagulation system during the development of EM and HAE attacks., Materials and Methods: Eight C1-INH-HAE patients (1 male, 7 females, median age: 41.7 years) were studied. Blood samples were obtained from all patients (during symptom-free periods, EM, and HAE attacks), as well as from 20 sex- and age-matched healthy controls. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, Factor V, Factor VII, Factor X, Factor XI, and Factor XII levels were measured., Results: D-dimer levels were significantly lower, whereas aPTT was significantly prolonged in healthy controls vs. the values measured during the symptom-free period (p = 0.0497; p = 0.0043), in the presence of EM (p = 0.002; p = 0.0002), or during HAE attacks (p < 0.0001; p = 0.0002). We observed the following differences between samples taken during HAE attacks vs. in symptom-free periods: D-dimer levels were significantly elevated (p = 0.0391), while aPTT was significantly shorter during HAE attacks (p = 0.0159). D-dimer levels were significantly higher during EM than in symptom-free periods (p = 0.0078). Comparing the samples drawn during EM or during HAE attacks, there were no significant differences in the study parameters., Conclusions: D-dimer levels were elevated during EM and this suggests that EM may be part of the HAE attack. Nevertheless, further research into the complement and kinin-kallikrein systems is needed in more patients for a better understanding of the pathomechanism of EM., Competing Interests: Declaration of Competing Interest K.V. Kőhalmi has received travel grants from CSL Behring and Shire. B. Mező, Sz. Benedek, A. Fehér, Á. Holdonner and M. Jesenak have no conflict of interest. N. Veszeli has received travel grants from CSL Behring. L. Varga has received travel grants from CSL Behring and Shire Human Genetic Therapies Inc. H. Farkas has received honoraria and travel grants from CSL Behring, Shire, Swedish Orphan Biovitrum, and Pharming; and/or served as a consultant for these companies and has participated in clinical trials/registries for BioCryst, CSL Behring, Pharming, and Shire., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1INH) is a rare genetic disease that runs in the family. As a result of the disease, acute swellings of the subcutaneous tissue and mucous membranes of the digestive and respiratory systems, including the larynx, occur. Any attack of the disease involving the throat and larynx is particularly dangerous and requires knowledge of clinical determinants of the disease and its proper management., Materials and Methods: The study included adult consecutive HAE-C1INH patients having follow-up visits in our centre. The group was examined with a structured clinical questionnaire, concerning the last 6 months and focusing particularly on laryngeal swelling attacks., Results: 55 subjects (F/M - 35/20, age range - 18-76) were included in the study. Laryngeal attacks occurred in 19 individuals (34.5%): 1-3, 4-6, and ≥7 attacks in 9, 8 and 2 patients, respectively, two of whom required intubation. In comparison to other patients, subjects with laryngeal attacks were characterised by significantly more frequent: (1) facial attacks, (2) severe disease activity, (3) the occurrence of female patients, (4) mental stress as a trigger of attacks. All patients with laryngeal attacks had a rescue medication at home and 15/19 (78%) patients could use it at home. Most of them used plasma-derived C1-inhibitor 17/19 (89.5%) and icatibant, 8/19 (42.1%)., Discussion: HAE-C1INH patients with laryngeal attacks require particular attention. Proper training regarding the identification of these patients, adequate management, access to emergency services and emergency drugs are essential to ensure the safety of subjects with this localization of HAE-C1INH attacks.

Despite the efficacy of the on-demand treatment for the control of acute attacks of Hereditary Angioedema due to C1-Inhibitor Deficiency (C1-INH-HAE), the number and severity of attacks and the impairment in the quality of life of the affected patients have led to the development of a new monoclonal antibody, lanadelumab, directly addressed to the blockage of bradykinin, the principal mediator of vasodilation during angioedema attacks. It is indicated for the prophylactic treatment, it is easy to administer, highly effective and with known limited side effects. The current review summarizes the development of the drug, its clinical background and its perspectives., Competing Interests: Dr Maria Bova reports personal fees and travel grants from Shire - ora Takeda, personal fees and travel grants from CSL behring, outside the submitted work; Dr Anna Valerieva reports grants from Bulgarian Ministry of Science under the National Program for Research, personal fees from Shire/Takeda, personal fees from Pharming Group N.V., personal fees from CSL Behring, outside the submitted work; Dr Riccardo Senter reports travel grants received by Shire-Takeda, CSL Behring, Biocryst and Novartis. The authors report no other conflicts of interests in this work., (© 2019 Bova et al.)

Hereditary angioedema (HAE) encompasses a heterogeneous group of diseases with similar phenotypes but different underlying genotypes. Specific clinical signs may point to HAE as opposed to histaminergic angioedema: the typical prolonged development of angioedema over time, positive family history, a lack of response to antihistamines and steroids and response to bradykinin antagonists are typical signs of HAE. The different types of HAE may be associated with a severe clinical course. They are life-long conditions and are still potentially life-threatening. The quality of life of patients with HAE may be considerably impaired. Management plans should be individualized, which is facilitated by the variety of specific medicastions available.

Background: Hereditary angioedema (HAE) is a rare but serious condition characterized by unpredictable and recurrent attacks affecting the skin and mucosa. HAE has wide-ranging impacts on the health-related quality of life (HRQoL) of patients. This study aims to assess the HRQoL of Chinese patients with HAE using the 36-item Short Form Health Survey (SF-36v2) and to explore potential risk factors for low HRQoL., Methods: A total of 104 patients (47 male and 57 female) over age 18 living in China with a known diagnosis of HAE due to C1-INH deficiency completed the SF-36v2 (generic HRQoL questionnaire). The results were compared to Chinese population norms. Subgroup analysis and logistic regression were used to interpret the data., Results: SF-36v2 showed a significant reduction in all dimensions of HRQoL (p < 0.001) in patients with HAE compared with the general Chinese population. Female patients reported significantly lower bodily pain (BP) (p = 0.039) and physical component scores (PCSs) (p = 0.027) than male patients. Patients with mucosal edema tended to report lower role-physical (RP) limitations (p = 0.031) than patients with only skin edema. There were no differences between the mean scores of the SF-36 in relation to disease subtype, age, disease severity and long-term prophylaxis. Among female patients on long-term prophylaxis, social functioning (SF) (r = - 0.404, p = 0.010), role-emotional (RE) (r = - 0.320, p = 0.044) and mental component scores (MCSs) (r = - 0.313, p = 0.049) were negatively correlated with danazol dosage. A correlation between decreased disease control and decreased HRQoL scores was found, although the correlation was not significant in terms of RE or mental health (MH) scores. The logistic regression model revealed uncontrolled disease to be a risk factor for a low PCS (odds ratio 10.77, 95% confidence interval [CI] 1.78-65.06; p = 0.010) and laryngeal edema to be a risk factor for a low MCS (odds ratio 4.75, 95% CI 1.09-20.69; p = 0.038)., Conclusions: Chinese HAE patients reported significantly lower HRQoL scores than the general population. Unsatisfactory disease control is a risk factor for decreased PCSs. Laryngeal edema is a risk factor for decreased MCSs.

Acquired C1-inhibitor (C1-INH) deficiency is a rare and potentially life-threatening disorder, which presents with recurrent attacks of non-pitting oedema to the face, airway, limbs or gastrointestinal tract. It is often associated with underlying B-cell lymphoproliferative disorders. We describe a case of a 73-year-old man with acquired C1-INH deficiency who presented with nephrotic syndrome due to glomerular IgM deposition, secondary to an underlying secretory lymphoplasmacytic lymphoma. Both the acquired C1-INH deficiency and the nephrotic syndrome resolved when the underlying B-cell lymphoma was treated with rituximab and bendamustine, suggesting the underlying lymphoproliferative malignancy was driving both disorders., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Data on the prevalence and clinical features of Austrian patients with hereditary angioedema (HAE) with C1-inhibitor (C1-INH) deficiency (HAE-1) or dysfunction (HAE-2) are lacking., Methods: Current baseline data were collected in a national survey. The records of HAE patients at the Medical University of Graz were analyzed with regard to clinical characteristics., Results: A total of 137 patients were identified, yielding a prevalence of 1 : 64,396. The median age at the onset of symptoms was 6.5 years, and the median age at the time of correct diagnosis 21.0 years. The median delay in diagnosis was 15.0 years for newly diagnosed patients without a family history of HAE. Patients with a family history of HAE received an immediate diagnosis. HAE patients without a family history of HAE and born before 1960 had to wait a median of 16.0 years until they were diagnosed correctly. Patients born after 1980 still experienced a median diagnostic delay of 6.5 years., Conclusion: Patients with this condition still face an excessive diagnostic delay in some parts of Austria, or their disorder may even remain unrecognized by specialists. This underlines the need for better awareness of the disease., (© 2019 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Background and Aims: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is characterized by localized, non-pitting, and transient swelling of submucosal or subcutaneous region. Human fetuin-A is a multifunctional glycoprotein that belongs to the proteinase inhibitor cystatin superfamily and has structural similarities to the high molecular weight kininogen. Fetuin-A is also known a negative acute phase reactant with anti-inflammatory characteristics. In this study we aimed to determine serum fetuin-A, C-reactive protein (CRP) and tumor necrosis factor alpha (TNFα) concentrations in patients with C1-INH-HAE during symptom-free period and during attacks and compare them to those of healthy controls. Further we analyzed possible relationship among these parameters as well as D-dimer levels which was known as marker of HAE attacks., Patients and Methods: Serum samples of 25 C1-INH-HAE patients (8 men, 17 women, age: 33.1 ± 6.9 years, mean ± SD) were compared to 25 healthy controls (15 men, 10 women, age: 32.5 ± 7.8 years). Serum fetuin-A and TNFα concentrations were determined by ELISA, CRP and D-dimer by turbidimetry., Results: Compared to healthy controls patients with C1-INH-HAE in the symptom-free period had significantly decreased serum fetuin-A 258 μg/ml (224-285) vs. 293 μg/ml (263-329), (median (25-75% percentiles, p = 0.035) and TNFα 2.53 ng/ml (1.70-2.83) vs. 3.47 ng/ml (2.92-4.18, p = 0.0008) concentrations. During HAE attacks fetuin-A levels increased from 258 (224-285) μg/ml to 287 (261-317) μg/ml (p = 0.021). TNFα and CRP levels did not change significantly. We found no significant correlation among fetuin-A CRP, TNFα and D-dimer levels in any of these three groups., Conclusions: Patients with C1-INH-HAE have decreased serum fetuin-A concentrations during the symptom-free period. Given the anti-inflammatory properties of fetuin-A, the increase of its levels may contribute to the counter-regulation of edema formation during C1-INH-HAE attacks.

Hereditary angioedema (HAE) is a relapsing swelling disorder which can cause severe pain, affect quality of life and potentially be life threatening with involvement of the airways. We present a 34-year-old immigrant who suffered from very frequent and severe HAE attacks. The attacks often involved the face, mouth and the airways. She often went to the hospital for treatment, where the language barrier made the situation complicated. The traditional therapy for HAE was not successful treating this patient. In June 2017, off-label treatment with prophylactic subcutaneous complement C1-inhibitor concentrate was initiated. The treatment was very successful and the patient has not been hospitalised since. Treatment for HAE is nowadays under investigation, and many drugs are under development. Especially, medication which works prophylactically and is administered orally or subcutaneously is in the horizon., Competing Interests: Competing interests: Anette Bygum has been involved in research and teaching activities with CSL Behring, Shire and Biocryst., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Hereditary angioedema (HAE) with C1 esterase inhibitor (C1-INH) deficiency (C1-INH-HAE) is a rare disease characterized by diminished levels or dysfunctional activity of C1-INH, leading to dysregulated plasma kallikrein activity within the kallikrein-kinin pathway. Symptoms manifest as painful, potentially life-threatening swelling of subcutaneous tissues throughout the body and/or submucosal edema in the upper airway or gastrointestinal tract. Attacks recur with unpredictable frequency, intensity, and duration, placing a heavy burden on patients' daily lives. Despite improved availability of medications for on-demand treatment during attacks and prophylaxis of future attacks, unmet needs remain. Lanadelumab, a fully human monoclonal antibody, may help address some of the limitations of existing prophylactic options (e.g., the need for intravenous administration or frequent dosing). Preclinical studies demonstrate that it is highly potent and specifically inhibits plasma kallikrein, and findings from phase Ia and Ib studies suggest this agent is well tolerated and provides sustained inhibition of plasma kallikrein, allowing for less frequent dosing. The phase III HELP Study (NCT02586805) evaluating the efficacy and safety of lanadelumab in preventing HAE attacks has been completed, and its open-label extension (NCT02741596) is ongoing. Lanadelumab is now approved in the USA and Canada for prophylaxis to prevent attacks of HAE in patients aged ≥ 12 years. This review provides an overview of the discovery and clinical development of lanadelumab, from preclinical through phase Ib studies, characterizing its safety/tolerability, efficacy, and pharmacokinetic and pharmacodynamic profiles. It also highlights how this agent may positively impact clinical care of patients with C1-INH-HAE.

Disclosures: Funding for this summary was contributed by the Laura and John Arnold Foundation, Blue Shield of California, and California Health Care Foundation to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from Aetna, AHIP Anthem, Blue Shield of California, CVS Caremark, Express Scripts, Harvard Pilgrim Health Care, Cambia Health Solutions, United Healthcare, Kaiser Permanente, Premera Blue Cross, AstraZeneca, Genentech, GlaxoSmithKline, Johnson & Johnson, Merck, National Pharmaceutical Council, Prime Therapeutics, Sanofi, Spark Therapeutics, Health Care Service Corporation, Editas, Alnylam, Regeneron, Mallinkrodt, Biogen, HealthPartners, and Novartis. Agboola, Dreitlein, and Pearson are ICER employees. Lin reports personal fees from ICER, during the conduct of this study, and grants from the National Institutes of Health and the California Department of Insurance, outside the submitted work. Carlson and Lubinga report grants from ICER, during the conduct of this study.

The plasma contact system contributes to thrombosis in experimental models. Even though our standard blood coagulation tests are prolonged when plasma lacks contact factors, this enzyme system appears to have a minor (if any) role in hemostasis. In this review, we explore the clinical phenotype of C1 esterase inhibitor (C1-INH) deficiency. C1-INH is the key plasma inhibitor of the contact system enzymes, and its deficiency causes hereditary angioedema (HAE). This inflammatory disorder is characterized by recurrent aggressive attacks of tissue swelling that occur at unpredictable locations throughout the body. Bradykinin, which is considered to be a byproduct of the plasma contact system during in vitro coagulation, is the main disease mediator in HAE. Surprisingly, there is little evidence for thrombotic events in HAE patients, suggesting mechanistic uncoupling from the intrinsic pathway of coagulation. In addition, it is questionable whether a surface is responsible for contact system activation in HAE. In this review, we discuss the clinical phenotype, disease modifiers and diagnostic challenges of HAE. We subsequently describe the underlying biochemical mechanisms and contributing disease mediators. Furthermore, we review three types of HAE that are not caused by C1-INH inhibitor deficiency. Finally, we propose a central enzymatic axis that we hypothesize to be responsible for bradykinin production in health and disease., (© 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Background: Management of patients with hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is evolving worldwide. Evaluating the Israeli experience may provide valuable insights., Objectives: To compare demographics and icatibant treatment patterns and outcomes in patients with C1-INH-HAE enrolled in the Icatibant Outcome Survey (IOS) in Israel with those in other countries., Methods: The IOS is an ongoing observational study that prospectively monitors real-world icatibant safety/tolerability and treatment outcomes., Results: By July 2016, 58 patients from Israel and 594 patients from other countries were enrolled. Median age at diagnosis (16.7 vs. 21.3 years, P = 0.036) and median delay between symptom onset and diagnosis (0.8 vs. 6.6 years, P = 0.025) were lower in Israel compared with other countries, respectively. Differences in attack severity were not significant (P = 0.156); however, during follow-up, Israeli patients were less likely to miss > 7 days of work/school due to C1-INH-HAE-related complications (P = 0.007). A trend was also shown in Israel for earlier time to treatment (median 0.5 vs. 1.3 hours, P = 0.076), attack duration was shorter (median 5.0 vs. 9.0 hours, P = 0.026), and patients more often self-administered icatibant (97.2% vs. 87.5%, P = 0.003), respectively. However, Israeli patients were less likely to treat attacks (P = 0.036). Whereas patients in Israel reported exclusive use of danazol for long-term prophylaxis, those in other countries used various agents, including C1-INH., Conclusions: Recognition of C1-INH-HAE and timeliness of icatibant treatment appear more favorable, and attack duration shorter, in Israel compared with other countries.

Recurrent angioedema (AE) without wheals is increasingly recognized as a clinical entity and a frequent cause of admission to the emergency room. The Hereditary Angioedema Working Group (HAWK) classification allowed the scientific community to go beyond the semantic confusion that dominated this topic for decades. This classification distinguishes hereditary and acquired forms of AE, either related or unrelated to C1 inhibitor deficiency. Recently, additional mechanisms have been involved in the AE pathogenesis, including the uncontrolled activation of factor XII, generation of vasoactive mediators that induce dysregulation of endothelial functions, and bidirectional interactions between mast cell-derived mediators and the plasma contact system. Thus, recurrent AE can be determined by multiple and concurrent mechanisms that may generate distinct clinical phenotypes of the disease. Frequency, severity, and the location of attacks are quite different from patient to patient and, even in the same patient, they may change throughout the course of life. The severity of the clinical phenotype strongly influences the burden of the disease and patients' quality of life. Despite major advances in our understanding of recurrent AE, many unsolved questions remain, leaving several unmet needs for patients and caregivers. This review is focused on a description of different AE phenotypes and the concurrent mechanisms leading to their pathogenesis. A better definition of cellular and molecular pathways responsible for the distinct AE phenotypes may help to improve diagnosis and may lead to a personalized approach to prophylaxis and treatment of the disease., (© 2018 S. Karger AG, Basel.)

Introduction: Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is a rare bradykinin-mediated disease characterized by recurrent subcutaneous and/or submucosal angioedematous attacks (HAE attacks), which occur unpredictably. The recurrent HAE attacks do not respond to conventional treatments, and may evolve into a life-threatening condition; therefore, special therapy is required., Areas Covered: The agents used so far for the acute management of HAE attacks act by blocking the release of bradykinin, or its binding to its receptor. By contrast, the investigational medicinal products under evaluation in Phase I and II clinical trials are targeted at the prevention of HAE attacks. Chemically, these new drugs are small synthetic molecules, oligonucleotides, or antibodies, which inhibit either kallikrein, or Factor XII., Expert Opinion: The key considerations for the development of new medicinal products include more straightforward dosing, self-administration, longer duration of action, and keeping the patient attack-free. This review summarizes the status and the findings of the currently ongoing Phase I and Phase II clinical trials of C1-INH-HAE.

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.

Background: Attacks of Hereditary Angioedema due to C1-inhibitor deficiency (C1-INH-HAE)are often triggered by stressful events/hormonal changes., Objective: Our study evaluates the relationship between autonomic nervous system (ANS) and contact/complement system activation., Methods: Twenty-three HAE patients (6 males, mean age 47.5±11.4 years) during remission and 24 healthy controls (8 males, mean age 45.3±10.6 years) were studied. ECG, beat-by-beat blood pressure, respiratory activity were continuously recorded during rest (10') and 75-degrees-head-up tilt (10'). C1-INH, C4, cleaved high molecular weight kininogen (cHK) were assessed; in 16 patients and 11 controls plasma catecholamines were also evaluated. Spectral analysis of heart rate variability allowed extraction of low-(LF) and high-(HF) frequency components, markers of sympathetic and vagal modulation respectively., Results: HAE patients showed higher mean systolic arterial pressure (SAP) than controls during both rest and tilt. Tilt induced a significant increase in SAP and its variability only in controls. Although sympathetic modulation (LFnu) increased significantly with tilt in both groups, LF/HF ratio, index of sympathovagal balance, increased significantly only in controls. At rest HAE patients showed higher noradrenaline values (301.4±132.9 pg/ml vs 210.5±89.6pg/ml, p = 0.05). Moreover, in patients tilt was associated with a significant increase in cHK, marker of contact system activation (49.5 ± 7.5% after T vs 47.1 ± 7.8% at R, p = 0.01)., Conclusions: Our data are consistent with altered ANS modulation in HAE patients, i.e. increased sympathetic activation at rest and blunted response to orthostatic challenge. Tilt test-induced increased HK cleavage suggests a link between stress and bradykinin production.

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.

Hereditary angioedema (HAE) is a genetic condition that is characterized by frequent episodes of localized angioedema. It is a rare disorder that a primary care provider, otolaryngologist, dermatologist, or rheumatologist may encounter only occasionally. This disease is being reviewed because of the significant advances in further understanding the genetics, biology, and therapeutic management surrounding the condition. Histamine-mediated angioedema responds to steroids, antihistamines, and epinephrine, whereas bradykinin-mediated angioedema is resistant to those interventions and requires specialized therapy. Previously used medications have significant adverse effects. Approved medications for HAE have been effective in decreasing morbidity and mortality in patients with this condition. We review the presentation, diagnosis, and available pharmaceutical options for HAE and explore the limitations of implementing recommended therapy.

The definition of angioedema is an edema of subcutaneous and submucosal tissues due to increased vascular permeability and fluid extravasation. It can affect different areas, including extremities, genitals, upper airways and intestinal mucosa. The symptoms are disabling and this condition can be fatal if it involves the larynx. We can distinguish different forms of angioedema (hereditary and acquired) with different pathogenetic mechanisms, therefore responding to different treatments. Bradykinin-mediated angioedema (such as hereditary angioedema due to C1-inhibitor deficiency) does not respond to the standard therapy used for histamine-mediated angioedema. These forms should be immediately recognized and specific treatment should be used. In addition, when a patient manifests hypotension not responding to fluid replacement and associated with diffuse edema, hypoalbuminemia and hemoconcentration, we should consider the diagnosis of idiopathic systemic capillary leak syndrome, a very rare but fatal condition.

Introduction: Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is a rare disease, characterized by recurrent, unpredictable episodes of cutaneous and/or mucosal edema. Bradykinin, released by the activation of the contact system, binds to bradykinin B2 receptors on the endothelial cell surface to enhance vascular permeaility, which leads to angioedema., Areas Covered: C1-INH-HAE therapy is aimed at the inhibition of bradykinin release, as well as at the blockage of its effects mediated by its receptor. Three controlled trials, three open-label extensions, and two open-label studies, and a prospective, observational study have confirmed the safety and efficacy of the bradykinin B2 receptor antagonist, icatibant administered as acute treatment for HAE attacks in adult patients with C1-INH-HAE. Expert commentary: The ready-to-use, pre-filled syringes of icatibant can be self-administered easily, effectively, safely and, importantly, conviently. - This has resulted in patients being able to quickly treat an attack and realize a dramatic change for the better in their lives.

Hereditary and acquired angioedema are potentially life-threatening diseases characterized by spontaneous episodes of subcutaneous and submucosal swelling of face, lips, oral cavity, larynx, and GI tract. Hereditary angioedema (HAE) usually presents within the first and second decades of life, whereas acquired angioedema presents in adults after 40 years of age. These clinical symptoms together with reduced C1 inhibitor levels and/or activity can usually confirm the diagnosis. In recent years, multiple novel therapies for treating hereditary angioedema have emerged including C1 inhibitor concentrates, ecallantide/kallikrein inhibitor, and icatibant/bradykinin receptor antagonist. This article reviews the clinical presentation, diagnosis, treatment, and prophylaxis of HAE. Lastly, this article takes into consideration that, in reality, acute care treatment can often be limited by each hospital's formulary, included is a review of HAE treatments available at the nine major hospitals in Rhode Island. [Full article available at http://rimed.org/rimedicaljournal-2016-06.asp, free with no login].

Hereditary angioedema attacks are rare, but emergency care providers must be aware of the clinical presentation and treatment of these patients because the emergency department remains the most common setting where these patients seek treatment. If providers are not aware of the past medical history of these patients, they are likely to receive standard therapies for respiratory distress and anaphylaxis including antihistamines, corticosteroids, and epinephrine. However, these medications may not work in these patients, given the pathophysiology of their underlying disease. Since 2009, several new therapies have been approved for the treatment of acute hereditary angioedema attacks. This article discusses pathophysiology, clinical presentation, and use of novel therapies for the management of angioedema.

Uncontrolled generation of bradykinin (BK) due to insufficient levels of protease inhibitors controlling contact phase (CP) activation, increased activity of CP proteins, and/or inadequate degradation of BK into inactive peptides increases vascular permeability via BK-receptor 2 (BKR2) and results in subcutaneous and submucosal edema formation. Hereditary and acquired angioedema due to C1-inhibitor deficiency (C1-INH-HAE and -AAE) are diseases characterized by serious and potentially fatal attacks of subcutaneous and submucosal edemas of upper airways, facial structures, abdomen, and extremities, due to inadequate control of BK generation. A decreased activity of C1-inhibitor is the hallmark of C1-INH-HAE (types 1 and 2) due to a mutation in the C1-inhibitor gene, whereas the deficiency in C1-inhibitor in C1-INH-AAE is the result of autoimmune phenomena. In HAE with normal C1-inhibitor, a significant percentage of patients have an increased activity of factor XIIa due to a FXII mutation (FXII-HAE). Treatment of C1-inhibitor-dependent angioedema focuses on restoring control of BK generation by inhibition of CP proteases by correcting the balance between CP inhibitors and BK breakdown or by inhibition of BK-mediated effects at the BKR2 on endothelial cells. This review will address the pathophysiology, clinical picture, diagnosis and available treatment in C1-inhibitor-dependent angioedema focusing on BK-release and its regulation. Key Messages Inadequate control of bradykinin formation results in the formation of characteristic subcutaneous and submucosal edemas of the skin, upper airways, facial structures, abdomen and extremities as seen in hereditary and acquired C1-inhibitor-dependent angioedema. Diagnosis of hereditary and acquired C1-inhibitor-dependent angioedema may be troublesome as illustrated by the fact that there is a significant delay in diagnosis; a certain grade of suspicion is therefore crucial for quick diagnosis. Submucosal edema formation in hereditary and acquired C1-inhibitor-dependent angioedema is potentially life threatening and can occur at any age. To date effective therapies for acute and prophylactic treatment are available.

Background: Hereditary angioedema (HAE) is a rare autosomal dominant primary immunodeficiency with complement system defect characterized by recurrent episodes of angioedema involving the skin or mucosa of the upper respiratory and gastrointestinal tracts., Objective: To characterize the clinical and laboratory data of hereditary angioedema in Iran., Methods: Patients with probable diagnosis of angioedema were enrolled in this study. Demographic and clinical data were documented in the designed questionnaire including history of attacks, triggering factors and laboratory data such as C4, C1 esterase inhibitor level and function., Results: Among 63 patients who were clinically suspicious for angioedema (23 males and 40 females), 8 cases (12.7%) were diagnosed with HAE. Among these 8 HAE patients, 3 were diagnosed with HAE type 1 and five patients were diagnosed with HAE type 2. The mean ages of HAE type 1 and type 2 patients were 25.6 ± 13.5 and 22.4 ± 12.32 years. The mean age of onset in HAE type 1 group was 8 ± 5 years and in HAE type 2 group was 18.8 ± 11.84 years. The mean diagnosis delay was 17.6 years in HAE type 1 patients and 2.6 years in HAE type 2. The most common clinical manifestation was facial swelling presented in all HAE patients followed by swelling of extremities which was present in 7 patients with HAE., Conclusion: The clinical criteria of the Iranian patients with HAE were consistent with the known clinical patterns of the disease.

Background: Early therapy of hereditary angioedema (HAE) decreases morbidity, improves outcomes, decreases absenteeism, and possibly decreases mortality. This can be accomplished best with self-therapy. Previously, the authors examined barriers to self-therapy from the perspective of the nurse and the physician, but data are lacking on what patients perceive as major barriers to self-administered therapy for HAE., Objective: To identify those barriers in a prospective fashion by patient interview., Methods: After approval from the institutional review board, a telephone survey was performed of patients with HAE from a database of patients who were recently seen in the clinic. The survey focused on anxiety, depression, stress, concerns regarding method of administration, the ability to inject themselves, and what they perceived as barriers to providing self-care., Results: Ninety-two patients were contacted and 59 agreed to participate. With 69% of those patients currently undergoing self-administered treatment, the results showed minimal depression and anxiety, a high satisfaction with treatment, and significant compliance with treatment. Most of those not yet on self-administered therapy wanted to start despite being satisfied with the care received in the emergency department. They also believed care at home would be optimal. The main concern of the 2 groups was not being able to treat themselves in the event of an HAE attack., Conclusion: From these data, it is obvious that most patients are willing to self-treat. This suggests that physicians should encourage self-treatment of HAE to improve outcomes and quality of life of patients with HAE., (Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)