Hereditary angioedema: the clinical syndrome and its management in the United States

Hereditary angioedema: Report of the dental treatment of 12 Brazilian patients

OBJECTIVE

The aim of this study was to report on clinical experience in Brazil in the dental treatment and the oral conditions of a group of patients with hereditary angioedema (HAE).

STUDY DESIGN

The study analyzed demographic data, type of HAE, intensity of attacks, long-term and short-term prophylaxis, dental procedures, and occurrence of crises after the procedures were performed. Radiographic evaluation of the number of teeth and bone loss was also performed.

RESULTS

Data from 12 patients were collected; most were women, presenting with C1-INH-HAE type I and a history of severe attacks. All patients reported use of regular medications (long-term prophylaxis), mostly attenuated androgens, to prevent/attenuate HAE attacks. These patients had several missing teeth and alveolar bone loss. Tooth extraction was the most common procedure. In half the patients, the procedures had been performed without modification in long-term prophylaxis. The others were treated with an additional prophylaxis protocol (short-term prophylaxis), particularly those who underwent tooth extraction. None of the study patients developed HAE attacks after dental procedures.

CONCLUSION

The occurrence and intensity of a possible HAE attack after dental procedures are unpredictable, but with careful preliminary screening by dental and immunology teams and the use of therapeutic prophylaxis, the risk could be minimized.

Hereditary Angioedema Type II: First Presentation in Adulthood with Recurrent Severe Abdominal Pain

A 27-year-old Emirate man presented to Cleveland Clinic Abu Dhabi emergency department with a 4 year history of recurrent episodes of severe swellings affecting different parts of his body. He used to get 2 swelling episodes every week affecting either his face, hands, feet or scrotum and severe abdominal pain twice a week. Abdominal CT scan and a colonoscopy showed bowel wall oedema. There was no family history of similar complaint or of hereditary angioedema (HAE). Complement studies confirmed the diagnosis of HAE type II. He was commenced on danazol 100 mg twice daily and his symptoms resolved. This case report highlights the importance of considering HAE in patients with recurrent unexplained abdominal pain even in the absence of positive family history of HAE.

An ABC of the Warning Signs of Hereditary Angioedema

Hereditary angioedema (HAE) with C1 inhibitor deficiency is a genetic disorder that clinically manifests with attacks of angioedema in the subcutaneous and submucosal tissues, mainly in the extremities, abdomen, and upper airway. During attacks, vascular permeability is increased due to increased bradykinin (BK). This means that special therapies are needed for attacks that do not respond to traditional antiallergic therapies involving antihistamines, corticosteroids, and epinephrine. The recurring attacks may disable patients and lead to frequent visits to emergency rooms where misdiagnoses are common. HAE attacks may be fatal when upper-airway edema occurs, if proper treatment with a C1 inhibitor concentrate or BK receptor antagonist is not administered or an emergency tracheostomy is not performed. We propose a mnemonic method for the warning signs of HAE for the use as a diagnostic tool, i.e., the so-called "ABC" of the warning signs of HAE. The letters represent the following: A = Angioedema, B = Bradykinin, C = C1 inhibitor, D = Distress factors, E = Epinephrine nonresponsive, F = Family history, and G = Glottis/Gastrointestinal edema. To avoid fatalities, medical staff and patients, including family members, must be aware of HAE. An alphabetical mnemonic method has been developed and we hope it may benefit patients.

Hereditary angioedema (HAE): a cause for recurrent abdominal pain

A 44-year-old Hispanic woman presented to the emergency room with a 2-day history of sudden onset of severe cramping left lower quadrant abdominal pain associated with ∼20 episodes diarrhoea. Abdominal CT scan exhibited bowel wall oedema and acute extensive colitis. On the basis of the preliminary diagnosis of acute abdomen, the patient was admitted under the surgical team and treated for acute colitis. Since her family history was significant for hereditary angioedema (HAE), complement studies were performed which revealed low complement C4 levels and abnormally low values of C1q esterase inhibitor. Thus, the diagnosis of HAE type I was established. This case report summarises that the symptoms of HAE are often non-specific, hence making the underlying cause difficult to diagnose.

Laboratory tests for disorders of complement and complement regulatory proteins

The complement pathway is a cascade of proteases that is involved in immune surveillance and innate immunity, as well as adaptive immunity. Dysfunction of the complement cascade may be mediated by aberrations in the pathways of activation, complement regulatory proteins, or complement deficiencies, and has been linked to a number of hematologic disorders, including paroxysmal noctural hemoglobinuria (PNH), hereditary angioedema (HAE), and atypical hemolytic-uremic syndrome (aHUS). Here, current laboratory tests for disorders of the complement pathway are reviewed, and their utility and limitations in hematologic disorders and systemic diseases are discussed. Current therapeutic advances targeting the complement pathway in treatment of complement-mediated hematologic disorders are also reviewed.

Phase II study results of a replacement therapy for hereditary angioedema with subcutaneous C1-inhibitor concentrate

BACKGROUND

Hereditary angioedema (HAE) due to C1 inhibitor deficiency manifests as recurrent swelling attacks that can be disabling and sometimes fatal. Long-term prophylaxis with twice-weekly intravenous injections of plasma-derived C1-inhibitor (pdC1-INH) has been established as an effective treatment. Subcutaneous (SC) administration of pdC1-INH has not been studied in patients with HAE.

METHODS

This open-label, dose-ranging, crossover study (COMPACT Phase II) was conducted in 18 patients with type I or II HAE who received two of twice-weekly 1500, 3000, or 6000 IU SC doses of highly concentrated volume-reduced CSL830 for 4 weeks each. The mean trough plasma levels of C1-INH functional activity, C1-INH and C4 antigen levels during Week 4, and overall safety and tolerability were evaluated. The primary outcome was model-derived steady-state trough C1-INH functional activity.

RESULTS

After SC CSL830 administration, a dose-dependent increase in trough functional C1-INH activity was observed. C1-INH and C4 levels both increased. The two highest dose groups (3000 and 6000 IU) achieved constant C1-INH activity levels above 40% values, a threshold that was assumed to provide clinical protection against angioedema attacks. Compared with intravenous injection, pdC1-INH SC injection with CSL830 showed a lower peak-to-trough ratio and more consistent exposures. All doses were well tolerated. Mild-to-moderate local site reactions were noted with pain and swelling being the most common adverse event.

CONCLUSIONS

Subcutaneous volume-reduced CSL830 was well tolerated and led to a dose-dependent increase in physiologically relevant functional C1-INH plasma levels. A clinical outcome study of SC CSL830 in patients with HAE warrants further investigation.

Hereditary Angioedema and Gastrointestinal Complications: An Extensive Review of the Literature

Hereditary Angioedema (HAE) is a rare autosomal dominant (AD) disease characterized by deficient (type 1) or nonfunctional (type 2) C1 inhibitor protein. The disorder is associated with episodes of angioedema of the face, larynx, lips, abdomen, or extremities. The angioedema is caused by the activation of the kallikrein-kinin system that leads to the release of vasoactive peptides, followed by edema, which in severe cases can be life threatening. The disease is usually not diagnosed until late adolescence and patients tend to have frequent episodes that can be severely impairing and have a high incidence of morbidity. Gastrointestinal involvement represents up to 80% of clinical presentations that are commonly confused with other gastrointestinal disorders such as appendicitis, cholecystitis, pancreatitis, and ischemic bower. We present a case of an HAE attack presenting as colonic intussusception managed conservatively with a C1 esterase inhibitor. Very few cases have been reported in the literature of HAE presentation in this manner, and there are no reports of any nonsurgical management of these cases.

Angioedema deaths in the United States, 1979-2010

BACKGROUND

Hospital admission data indicate that the angioedema incidence has increased during the past several decades. Little is known about mortality trends.

OBJECTIVES

To count the number of deaths associated with angioedema in the United States, investigate correlations with age, sex, race, and other contributory causes, and analyze trends from 1979 to 2010.

METHODS

All US death certificates in which angioedema was listed as an underlying or contributing cause of death during 1979 to 2010 were analyzed. Age-adjusted mortality rates were analyzed by age, sex, and race. Other conditions designated as the underlying cause of death were investigated.

RESULTS

From 1979 to 2010, there were 5,758 deaths in which angioedema was listed as a contributing cause. The age-adjusted death rate for hereditary angioedema decreased from 0.28 (95% confidence interval [CI] 0.25-0.32) to 0.06 (95% CI 0.05-0.08) per million persons per year. Conversely, mortality for angioedema increased from 0.24 (95% CI 0.21-0.27) to 0.34 (95% CI 0.31-0.37) per million. Blacks constituted 55% of angioedema deaths that were associated with use of angiotensin-converting enzyme inhibitors. On death certificates that listed hereditary angioedema as the underlying cause of death, cancer (frequently lymphoma or leukemia) was the second most commonly listed cause.

CONCLUSION

Angioedema-associated deaths were very rare from 1979 to 2010. Hereditary angioedema deaths became even more so, whereas nonhereditary angioedema deaths increased. Risks associated with angiotensin-converting enzyme inhibitors were higher in blacks. Lack of specific coding for acquired angioedema most likely explains the observed association between cancer and hereditary angioedema. In the future, more granular coding systems may help distinguish hereditary from acquired angioedema.

Hereditary angioedema: imaging manifestations and clinical management

Hereditary angioedema is a genetic disorder typically related to insufficient or dysfunctional C1-esterase inhibitor. Patients present with episodic swelling of various body parts, such as the face, neck, bowel, genitals, and extremities. Acute or severe symptoms can lead to patients presenting to the emergency room, particularly when the neck and abdominopelvic regions are affected, which is often accompanied by radiologic imaging evaluation. Patients with hereditary angioedema can pose a diagnostic challenge for emergency department physicians and radiologists at initial presentation, and the correct diagnosis may be missed or delayed, due to lack of clinical awareness of the disease or lack of its consideration in the radiologic differential diagnosis. Timely diagnosis of hereditary angioedema and rapid initiation of appropriate therapy can avoid potentially life-threatening complications. This article focuses on the spectrum of common and characteristic acute imaging manifestations of hereditary angioedema and provides an update on important recent developments in its clinical management and treatment.

Current update on cellular and molecular mechanisms of hereditary angioedema

OBJECTIVE

To provide an update on the molecular mechanisms of hereditary angioedema (HAE).

DATA SOURCES

MEDLINE and PubMed databases were searched to identify pertinent articles using the following key terms: hereditary angioedema, angioedema, C1 inhibitor, bradykinin, contact system, factor XII, mechanism, pathophysiology, severity, permeability, and estrogen.

STUDY SELECTIONS

Articles were selected based on their relevance to the subject matter.

RESULTS

Although the biochemical basis of "classic" HAE is known to result from C1 esterase inhibitor (C1INH) deficiency, a new form, HAE with normal C1INH, has been identified. HAE types I and II are caused by mutations in the SERPING1 gene that result in decreased plasma levels of functional C1INH. In HAE with normal C1INH, mutations in the F12 gene have been identified in a subset of individuals, but the genetic defect remains unknown in most patients. The primary mediator of swelling in HAE is bradykinin, a product of the plasma contact system that increases vascular permeability. HAE disease severity is highly variable and may be influenced by polymorphisms in other genes and other factors, such as hormones, trauma, stress, and infection.

CONCLUSION

Hereditary angioedema is a heterogeneous disorder with a complex pathophysiology. Implicated genes include SERPING1 and FXII in patients with HAE from C1INH deficiency and HAE with normal C1INH levels, respectively. Disease severity is highly variable.

US Hereditary Angioedema Association Medical Advisory Board 2013 recommendations for the management of hereditary angioedema due to C1 inhibitor deficiency

BACKGROUND

The treatment of hereditary angioedema (HAE) has undergone dramatic changes as newer medicines have become available in recent years. Optimal care of these patients requires a comprehensive management plan. Although several consensus papers have been published concerning the diagnosis and treatment of HAE, guidelines for a comprehensive management plan have not been developed.

OBJECTIVE

To develop state-of-the-art recommendations for the treatment and management of HAE due to C1 inhibitor (C1INH) deficiency in the United States.

METHODS

Members of the US Hereditary Angioedema Association Medical Advisory Board began by reviewing the literature concerning treatment of HAE. Preliminary recommendations were developed based on the literature review, discussions in a face-to-face meeting, and refinements in a series of drafts. Final recommendations reflect the unanimous consensus of the medical advisory board and the US Hereditary Angioedema Association leadership.

RESULTS

Recommendations are provided regarding a comprehensive care plan for HAE, including the following: development of an overall management plan, treatment of angioedema attacks, prophylactic treatment, and patient monitoring.

CONCLUSION

A comprehensive individualized management plan developed between an expert HAE physician and the patient, in collaboration with local medical providers and emergency departments, can provide patients with the best opportunity to lead a normal life.

Leukocytosis and high hematocrit levels during abdominal attacks of hereditary angioedema

BACKGROUND

The diagnosis of hereditary angioedema (HAE) is often delayed due to the low awareness of this condition. In patients with undiagnosed HAE, abdominal symptoms often create the risk of unnecessary surgical operation and/or drug therapy. To explore the cause of misdiagnosis, we compared the laboratory findings of HAE patients under normal conditions with those during abdominal attacks.

METHODS

Patient medical histories were analyzed and laboratory data at the first consultation with no symptoms and no medication were compared with those at visits to the emergency department during severe attacks.

RESULTS

Fourteen HAE patients were enrolled. Initial HAE symptoms occurred at 20.2 ± 9.4 years of age. The correct diagnosis of HAE was made 22.7 ± 14.2 years after the initial symptoms. A common site of angioedema was the extremities. Half of the patients experienced a life-threatening laryngeal attack and/or severe abdominal pain. In the patients with severe abdominal pain, significant leukocytosis with neutrophilia along with increased levels of hematocrit were observed while levels of C-reactive protein (CRP) remained low. All severe attacks were alleviated with an infusion of C1-inhibitor concentrate.

CONCLUSIONS

Consideration of the likelihood of a HAE attack is important when patients present with acute abdominal pain and leukocytosis without elevation of CRP.

Cost-utility analysis of Ruconest(®) (conestat alfa) compared to Berinert(®) P (human C1 esterase inhibitor) in the treatment of acute, life-threatening angioedema attacks in patients with hereditary angioedema

INTRODUCTION

Administration of human C1 esterase inhibitor (Berinert(®) P) from target import is the most widespread treatment strategy for patients with hereditary angioedema (HAE). However, a therapeutic health program including Ruconest(®) (conestat alfa) could shorten a patient's expectancy for a life-saving treatment.

AIM

To evaluate the cost-utility of Ruconest(®) (conestat alfa) financed from public funds within the newly introduced therapeutic health program compared with Berinert(®) P (human C1 esterase inhibitor) in the treatment of acute angioedema attacks in adults with HAE.

MATERIAL AND METHODS

The cost-utility analysis from the Polish healthcare payer's perspective was performed for 1 year (2012). The costs and health outcomes were simulated for three pairs of eligible HAE patient groups (active treatment and corresponding placebo). The incremental costs of each intervention compared with placebo were listed together (direct or indirect comparisons between options were impossible due to limited clinical data available).

RESULTS

The incremental cost-utility ratios (ICURs) for the evaluated interventions compared with placebo were as follows: EUR 15,226 per QALY (Ruconest(®)) and EUR 27,786 per QALY (Berinert(®) P). The probability of cost-utility (ICUR < EUR 24,279 per QALY) assessed for Ruconest(®) administered in the case of acute angioedema attack was 61% and 41% for Berinert(®) P.

CONCLUSIONS

The administration of Ruconest(®) in acute life-threatening angioedema attacks is economically justified from the Polish healthcare payer's perspective, results in lower costs and is characterized by higher cost-utility probability compared with Berinert(®) P.

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.

Safety and efficacy of prophylactic nanofiltered C1-inhibitor in hereditary angioedema

OBJECTIVE

Nanofiltered C1-inhibitor (C1INH-nf) is approved for prophylactic treatment of hereditary angioedema. This study assessed the efficacy and safety of C1INH-nf as prophylactic therapy in a large cohort of patients with hereditary angioedema.

METHODS

An open-label multicenter extension study was performed involving 146 subjects with hereditary angioedema who were treated with C1INH-nf for up to 2.6 years in centers throughout the United States. Subjects were to be treated with C1INH-nf 1000 units every 3 to 7 days. The primary efficacy variable was the number of attacks of angioedema experienced.

RESULTS

Subjects experienced a 93.7% reduction in attacks while taking prophylactic C1INH-nf (0.19 attacks per month; interquartile range, 0.00-0.64) compared with the historical rate of attacks. Some 87.7% reported an attack frequency of 1 or less attack per month during prophylactic C1INH-nf and 34.9% had no attacks during the study. Some 7.5% of subjects experienced relatively frequent attacks despite twice-weekly C1INH-nf. Although twice-weekly dosing was highly effective in most subjects, once-weekly dosing provided adequate control in a subgroup of subjects. No clinical characteristics predicted the response to prophylactic C1INH-nf, including historical attack frequency. C1INH-nf was well tolerated.

CONCLUSION

Prophylactic C1INH-nf is highly effective and safe, and provides durable prophylaxis in the majority of patients with hereditary angioedema. The recommended dose of C1INH-nf 1000 units twice weekly is supported by this open-label study. Individual patients may benefit from further dose adjustment on the basis of response to therapy and individual treatment goals.

Human Plasma-Derived, Nanofiltered, C1-Inhibitor Concentrate (Cinryze®), a Novel Therapeutic Alternative for the Management of Hereditary Angioedema Resulting from C1-Inhibitor Deficiency

Hereditary angioedema resulting from the deficiency of the C1 inhibitor (HAE-C1-INH) is a rare, but potentially life-threatening disorder characterized by paroxysmal episodes of subcutaneous or submucosal edema. Early diagnosis is essential. Management is aimed at the prompt elimination of full-fledged attacks, as well as at the prevention of edematous episodes. The most straightforward means for therapy is supplementation with the deficient C1-INH protein. Placebo-controlled and open clinical studies have established that nanofiltered, human C1-INH concentrate, Cinryze® (ViroPharma Inc., Exton, PA, USA) (C1-INH_Ci), administered in 1,000 U doses is an effective and safe remedy for edematous episodes of HAE-C1-INH, regardless of the localization of the attack. Clinical manifestations rapidly improve and then resolve completely following treatment with this medicinal product. Additionally, C1-INH_Ci is also appropriate for pre-procedural or for routine prophylaxis. The administration of 1,000 U C1-INH_Ci before the (dental, surgical, or interventional diagnostic) procedure reduced the incidence of edematous episodes compared with placebo, and this reduction proved significant during routine prophylaxis with the administration of this dose every 3–4 days. Relapses did not occur, and repeated dosing had no influence on the efficacy of the preparation. Patients also tolerated treatment with C1-INH_Ci well. The safety of this preparation was confirmed by the absence of viral transmission as well as by the lack of antibody formation against C1-INH during treatment. Nowadays, C1-INH_Ci for intravenous use is the only medicinal product indicated both for the prevention and management of edematous attacks.

The dermatology view of hereditary angio-oedema: practical diagnostic and management considerations

Hereditary angio-oedema (HAE) is characterized by recurrent, localized, non-pitting, non-pruritic, non-urticarial oedema. Nearly all patients experience skin swelling as a feature of HAE. There may be painful abdominal attacks, accompanied by nausea and vomiting. The disease is life-threatening should laryngeal oedema occur. HAE results from a deficiency or dysfunction of C1 inhibitor, a plasma protein with an important role in regulating the contact, complement and fibrinolytic systems. Effective management of HAE should include a plan for treatment of attacks, as well as routine and preprocedure prevention. Acute and prophylactic therapy with C1 inhibitor therapy for correcting the underlying deficiency in HAE is a valuable option.

Life with hereditary angioedema: then and now

Originally identified in 1882, hereditary angioedema (HAE) is a debilitating and potentially fatal disorder. Although a number of therapies have been identified, many are relatively ineffective or are associated with significant side effect concerns that limit their efficacy. Fortunately, the 2008 approval of plasma-derived C1 esterase inhibitor concentrate for disease prophylaxis provides clinicians with a novel and effective treatment unencumbered with severe side effect concerns for those with this debilitating disorder. However, despite advances in modern medicine, HAE remains a condition marked by a myriad of symptoms that mimic a range of other disorders, from allergic angioedema to acute abdomen, and accurate diagnosis remains a concern. Using articles from the medical literature from the late nineteenth and early twentieth centuries documenting families with HAE, we will review its history and pathophysiology as well as describe current trends in its diagnosis and treatment. Additionally, we will emphasize the humanistic impact of the disorder by describing the real-life experiences of a contemporary family who has documented their experience with HAE across 7 generations.

Hereditary angioedema therapies in the United States: movement toward an international treatment consensus

BACKGROUND

Hereditary angioedema (HAE) is a rare, potentially life-threatening autosomal dominant disease characterized by recurrent angioedema attacks that affect the skin, gastrointestinal tract, and airway, including the larynx. Pharmacologic developments in HAE treatment have culminated in the recent introduction of 4 new HAE-specific therapies in the United States.

OBJECTIVES

In light of these new therapeutic options, this commentary outlines historical US HAE therapy choices, discusses the potential effect of the 4 recently approved HAE treatments, and considers strategies for optimizing their use in line with international treatment recommendations.

DISCUSSION

Treatment options for HAE in the United States have been limited to attenuated androgens and antifibrinolytic agents for long-term prophylaxis and FFP and supportive therapy for the management of acute attacks. The 4 new therapies that have recently become available (ie, 2 plasma-derived C1 esterase inhibitor (C1-INH) concentrates, the kallikrein inhibitor ecallantide, and the bradykinin β(2)-antagonist icatibant) have provided an opportunity to change routine HAE treatment. In 2009, despite the availability of 2 of the new treatments (ie, the plasma-derived C1-INH concentrates), a large survey of US physicians suggested that wide variability still existed in the treatment of patients with HAE. Since this survey was undertaken, clinical experience with all 4 new treatments has increased significantly, and because 3 of these agents (ie, 2 plasma-derived C1-INH concentrates and icatibant) can be self-administered by trained patients, physicians can now provide individualized care that is proven effective and more aligned with international guidance.

Diagnosis and management of hereditary angioedema: an emergency medicine perspective

BACKGROUND

Hereditary angioedema (HAE) is a rare and often debilitating condition associated with substantial morbidity and mortality in the absence of appropriate intervention. An underlying deficiency in functional C1-inhibitor (C1-INH) protein induces a vulnerability to unchecked activation of the complement, contact, and coagulation/fibrinolytic systems. The clinical consequence is a pattern of recurring attacks of non-pitting, non-pruritic edema, the urgency of which varies by the affected site. Laryngeal edema can escalate rapidly to asphyxiation, and severe cases of abdominal swelling can lead to hypovolemic shock.

OBJECTIVES

This report reviews the emergency diagnosis and treatment of hereditary angioedema and the impact of recently introduced treatments on treatment in the United States.

DISCUSSION

Until recently, emergency physicians in the United States were hindered by the lack of rapidly effective treatment options for HAE attacks. In this article, general clinical and laboratory diagnostic procedures are reviewed against the backdrop of two case studies: one patient presenting with a known history of HAE and one with previously undiagnosed HAE. In many countries outside the United States, plasma-derived C1-INH concentrate has for decades been the first-line treatment for acute attacks. The end of 2009 ushered in a new era in the pharmacologic management of HAE attacks in the United States with the approval of two new treatment options for acute treatment: a plasma-derived C1-INH concentrate and a kallikrein inhibitor.

CONCLUSION

With access to targeted and effective treatments, emergency physicians are now better equipped for successful and rapid intervention in urgent HAE cases.

Urticaria and angioedema

Urticaria and angioedema are common disorders that can severely impair the quality of a patient's life and can be extremely difficult to treat. Symptoms can persist for years to decades. The causes of urticaria and angioedema are varied and may be immunologic, nonimmunologic, or idiopathic. This article reviews the literature and provides primary care physicians with up-to-date information of the epidemiology, basic pathophysiology, diagnosis, and management of this common and often debilitating condition. Additionally, clinical manifestations of acute and chronic urticaria, hereditary and acquired angioedema, as well as the physical urticarias will be discussed.

[Hereditary angioedema: a therapeutic revolution]

Hereditary angioedema is a rare disease, often diagnosed with delay because of a heterogeneous clinical presentation. Before diagnosis, patients frequently present subcutaneous edema or abdominal pains during many years. Laryngeal edema can be life-threatening. Hereditary angioedema may impair the quality of life of the patients and their social and professional life. It is important that the physicians recognize and treat the disease as soon as possible after the first attacks. Since the past five years, new drugs developed for hereditary angioedema have changed dramatically the outcome of this disorder. The objective of this review is to detail the new therapeutic guidelines.

Conestat alfa for the treatment of angioedema attacks

Recently, multiple C1 inhibitor (C1-INH) replacement products have been approved for the treatment of hereditary angioedema (HAE). This review summarizes HAE and its current treatment modalities and focuses on findings from bench to bedside trials of a new C1-INH replacement, conestat alfa. Conestat alfa is unique among the other C1-INH replacement products because it is produced from transgenic rabbits rather than derived from human plasma donors, which can potentially allow an unlimited source of drug without any concern of infectious transmission. The clinical trial data generated to date indicate that conestat alfa is safe and effective for the treatment of acute HAE attacks.

[Acute pancreatitis associated with hereditary angioedema]

Hereditary angioedema (HAE) is an infrequent, recurrent, and potentially lethal disorder caused by a deficiency of C(1) inhibitor or its activity. Abdominal pain secondary to bowel edema is common in these patients. However, a thorough literature search yielded only six previously reported cases of pancreatitis associated with this entity.

Long-term efficacy of danazol treatment in hereditary angioedema

BACKGROUND

No systematic study has been published yet on the long-term efficacy of attenuated androgens in hereditary angioedema (HAE). Our aim was to conduct a follow-up study in two (German and Hungarian) cohorts of HAE patients (45 and 39 patients, respectively) undergoing uninterrupted treatment for 6 years with similar (starting dose 128 ± 78 mg per day and 136 ± 70 mg per day, respectively) and constant doses of danazol.

DESIGN

The frequencies of subcutaneous, abdominal and laryngeal attacks were recorded each year.

RESULTS

The annual frequency of all the three types of attacks was significantly lower during the first year of danazol treatment, compared to the last year before baseline. During subsequent years in Hungarian patients, the frequency of both subcutaneous and abdominal attacks - but not that of laryngeal attacks - increased significantly. In the case of abdominal attacks, a significant increase in the attack frequency was observed only in female patients. In the German cohort, by contrast, no change in the frequency of either type of attack was found during the 6-year study period.

CONCLUSIONS

The differences observed between these cohorts cannot be related to drug dose, the age or gender distribution of subjects or the age at the onset of symptoms or the length of diagnostic delay in the patients. There were, however, marked differences in the baseline pattern of attacks: significantly - 3 times - more abdominal attacks were recorded in German patients. Further studies are necessary to clarify the mechanism of these findings.

Treatment of laryngeal hereditary angioedema

BACKGROUND

In the emergency department, patients with laryngeal swelling and an inconclusive patient history may receive treatment for allergy-mediated angioedema. Intubation may be necessary if the patient does not respond to treatment. Because angioedema subtypes respond to different interventions, a correct diagnosis is vital.

OBJECTIVES

Review the differential diagnosis of angioedema and characteristics differentiating subtypes. Discuss therapies for angioedema subtypes. Introduce therapies for prevention and acute treatment of hereditary angioedema (HAE).

CASE REPORT

A 10-year-old girl presented with laryngeal swelling unresponsive to diphenhydramine, methylprednisolone, and epinephrine. It was later revealed that she had a family history of HAE, was C1 inhibitor deficient, and enrolled in a clinical study of acute HAE treatment. She was given 1000 units of nanofiltered C1 inhibitor and was able to swallow within 30 min. She was prescribed routine prophylaxis with C1 inhibitor concentrate and has had no subsequent severe HAE swelling attacks.

CONCLUSION

This case illustrates the need for providers to consider HAE in light of available diagnostic testing and recent Food and Drug Administration approval of specific therapies for HAE.

Current medical management of hereditary angioedema: results from a large survey of US physicians

BACKGROUND

Hereditary angioedema (HAE) is a potentially life-threatening condition that affects approximately 1 in 50,000 persons. There are no known surveys of US physicians' knowledge and experience regarding the epidemiology, diagnosis, and management of HAE.

OBJECTIVE

This survey of physicians treating patients with HAE assessed physician characteristics, diagnostic and treatment practices, factors that influence physician and patient treatment choices, and physician awareness of new therapies.

METHODS

From October 2009 to February 2010, physicians (N = 172) voluntarily completed an online survey developed by physician-investigators. Data were analyzed with descriptive statistics.

RESULTS

Most physicians (73.8%) managed 5 patients or fewer in diverse practice settings. Laboratory testing was considered most important in establishing a diagnosis. Fresh frozen plasma and C1 esterase inhibitors were the most frequently administered treatments for acute events; nearly 50% of respondents prescribed C1 esterase inhibitor for acute attacks. More than 80% of respondents prescribed androgens for long-term prophylaxis. Approximately half of respondents were aware of, and likely to use, new therapies for HAE. Other than efficacy, adverse effects were the most important factor that influenced physicians' treatment recommendations, whereas physicians perceived that patients were most influenced by adverse effects and cost.

CONCLUSIONS

Wide variability exists in the treatment of patients with HAE. Many patients experience acute attacks that require emergency care or hospitalization. Androgens and fresh frozen plasma are frequently used despite recent availability of effective condition-specific agents, and many physicians are only somewhat aware of medications newly approved by the US Food and Drug Administration. Because the survey was completed shortly after approval of additional HAE therapies by the US Food and Drug Administration, these data will be useful for tracking changes in HAE treatment over time.

Brazilian guidelines for the diagnosis and treatment of hereditary angioedema

Hereditary angioedema is an autosomal dominant disease characterized by edema attacks with multiple organ involvement. It is caused by a quantitative or functional deficiency of the C1 inhibitor, which is a member of the serine protease inhibitor family. Hereditary angioedema is unknown to many health professionals and is therefore an underdiagnosed disease. The causes of death from hereditary angioedema include laryngeal edema with asphyxia. The estimated mortality rate in patients in whom the disease goes undetected and who are therefore incorrectly treated is 25-40%. In addition to edema of the glottis, hereditary angioedema often results in edema of the gastrointestinal tract, which can be incapacitating. Patients with hereditary angioedema may undergo unnecessary surgical interventions because the digestive tract can be the primary or only organ system involved, thus mimicking acute surgical abdomen. It is estimated that patients with hereditary angioedema experience some degree of disability 20-100 days per year. The Experts in Clinical Immunology and Allergy of the "Associação Brasileira de Alergia e Imunopatologia -ASBAI" developed these guidelines for the diagnosis, therapy, and management of hereditary angioedema.

Recent developments in the treatment of acute abdominal and facial attacks of hereditary angioedema: focus on human C1 esterase inhibitor

Hereditary angioedema (HAE) is a potentially fatal genetic disorder typified by a deficiency (type I) or dysfunction (type II) of the C1-inhibitor (C1-INH) and characterized by swelling of the extremities, face, trunk, abdominal viscera, and upper airway. Type III is normal estrogen-sensitive C1-INH HAE. Bradykinin, the main mediator of HAE, binds to endothelial B2 receptors, increasing vascular permeability and resulting in edema. HAE management includes short- and long-term prophylaxis. For treating acute episodes, C1-INH concentrate is recommended with regression of symptoms achieved in 30-90 min. Infusions of 500-1000 U have been used in Europe for years. Two plasma-derived C1-INH concentrates have been licensed recently in the United States: Berinert(®) for treating acute attacks and Cinryze(®) for prophylaxis in adolescent/adult patients. A recombinant C1-INH that is being considered for approval (conestat alfa) exhibited significant superiority versus placebo. Ecallantide (Kalbitor(®)) is a selective kallikrein inhibitor recently licensed in the United States for treating acute attacks in patients aged >16 years. It is administered in three 10-mg subcutaneous injections with the risk of anaphylactic reactions. Icatibant (Firazyr(®)) is a bradykinin B2 receptor competitor. It is administered subcutaneously as a 30-mg injection and approved in Europe but not in the United States.

An overview of novel therapies for acute hereditary angioedema

Hereditary angioedema is an episodic swelling disorder with autosomal dominant inheritance. Attacks are characterized by nonpitting edema of external or mucosal body surfaces. Patients often present with swelling of the extremities, abdominal pain, and swelling of the mouth and throat, which can at times lead to asphyxiation. The disease is caused by a mutation in the gene encoding the complement C1-inhibitor protein, which leads to unregulated production of bradykinin. Long-term therapy has depended on the use of attenuated androgens or plasmin inhibitors but in the US there was, until recently, no specific therapy for acute attacks. As well, many patients with hereditary angioedema in the US were either not adequately controlled on previously available therapies or required doses of medications that exposed them to the risk of serious adverse effects. Five companies have completed or are currently conducting phase III clinical trials in the development of specific therapies to terminate acute attacks or to be used as prophylaxis. These products are based on either replacement therapy with purified plasma-derived or recombinant C1-inhibitor, or inhibition of the kinin-generating pathways with a recombinant plasma kallikrein inhibitor or bradykinin type 2 receptor antagonist. Published studies thus far suggest that all of these products are likely to be effective. These new therapies will likely lead to a totally new approach in treating hereditary angioedema.

Successful C1 inhibitor short-term prophylaxis during redo mitral valve replacement in a patient with hereditary angioedema

Hereditary angioedema is characterized by sudden episodes of nonpitting edema that cause discomfort and pain. Typically the extremities, genitalia, trunk, gastrointestinal tract, face, and larynx are affected by attacks of swelling. Laryngeal swelling carries significant risk for asphyxiation. The disease results from mutations in the C1 esterase inhibitor gene that cause C1 esterase inhibitor deficiency. Attacks of hereditary angioedema result from contact, complement, and fibrinolytic plasma cascade activation, where C1 esterase inhibitor irreversibly binds substrates. Patients with hereditary angioedema cannot replenish C1 esterase inhibitor levels on pace with its binding. When C1 esterase inhibitor is depleted in these patients, vasoactive plasma cascade products cause swelling attacks. Trauma is a known trigger for hereditary angioedema attacks, and patients have been denied surgical procedures because of this risk. However, uncomplicated surgeries have been reported. Appropriate prophylaxis can reduce peri-operative morbidity in these patients, despite proteolytic cascade and complement activation during surgical trauma. We report a case of successful short-term prophylaxis with C1 esterase inhibitor in a 51-year-old man with hereditary angioedema who underwent redo mitral valve reconstructive surgery.

Hereditary angioedema in childhood: an approach to management

Hereditary angioedema (HAE) is an inherited disorder characterized by recurrent, circumscribed, non-pitting, non-pruritic, and rather painful subepithelial swelling of sudden onset, which fades during the course of 48-72 hours, but can persist for up to 1 week. Lesions can be solitary or multiple, and primarily involve the extremities, larynx, face, esophagus, and bowel wall. Patients with HAE experience angioedema because of a defective control of the plasma kinin-forming cascade that is activated through contact with negatively charged endothelial macromolecules leading to binding and auto-activation of coagulation factor XII, activation of prekallikrein to kallikrein by factor XIIa, and cleavage of high-molecular-weight kininogen by kallikrein to release the highly potent vasodilator bradykinin. Three forms of HAE have currently been described. Type I and type II HAE are rare autosomal dominant diseases due to mutations in the C1-inhibitor gene (SERPING1). C1-inhibitor mutations that cause type I HAE occur throughout the gene and result in truncated or misfolded proteins with a deficiency in the levels of antigenic and functional C1-inhibitor. Mutations that cause type II HAE generally involve exon 8 at or adjacent to the active site, resulting in an antigenically intact but dysfunctional mutant protein. In contrast, type III HAE (also called estrogen-dependent HAE) is characterized by normal C1-inhibitor activity. The diagnosis of HAE is suggested by a positive family history, the absence of accompanying pruritus or urticaria, the presence of recurrent gastrointestinal attacks of colic, and episodes of laryngeal edema. Estrogens may exacerbate attacks, and in some patients attacks are precipitated by trauma, inflammation, or psychological stress. For type I and type II HAE, diminished C4 concentrations are highly suggestive for the diagnosis. Further laboratory diagnosis depends on demonstrating a deficiency of C1-inhibitor antigen (type I) in most kindreds, but some kindreds have an antigenically intact but dysfunctional protein (type II) and require a functional assay to establish the diagnosis. There are no particular laboratory findings in type III HAE. Prophylactic administration of either 17alpha-alkylated androgens or synthetic antifibrinolytic agents has proven useful in reducing the frequency or severity of attacks. Plasma-derived C1-inhibitor concentrate, recombinant C1-inhibitor, ecallantide (DX88; a plasma kallikrein inhibitor) and icatibant (a bradykinin B(2) receptor antagonist) have demonstrated significant efficacy in the treatment of acute attacks, whereas the C1-inhibitor concentrate has also provided a significant benefit as long-term prophylaxis. However, these drugs are not licensed in all countries and are not always readily available.

Hereditary angioedema: New therapeutic options for a potentially deadly disorder

Although the biochemistry of hereditary angioedema (HAE) is fairly well understood today, the lag in diagnosis of a decade or more suggests that clinicians have low awareness of this disease. This lag in diagnosis and hence treatment certainly stems from the rarity and complexity of the presentation which can be easily mistaken for allergic and non-allergic reactions alike. The symptoms of the disease include acute swelling of any or multiple parts of the body. The attacks may be frequent or rare, and they may vary substantially in severity, causing stomach discomfort or periorbital swelling in mild cases and hypovolemic shock due to abdominal fluid shift or asphyxiation in the most severe cases. Given that these patients are at significant risk for poor quality of life and death, greater awareness of this disease is needed to ensure that newly available, effective medications are used in these patients. These new medications represent significant advances in HAE therapy because they are targeted at the plasma cascades implicated in the pathophysiology of this disease. The clinical presentation of HAE, overlapping symptoms with other angioedemas, and available therapies are reviewed.

Treatment of episodes of hereditary angioedema with C1 inhibitor: serial assessment of observed abnormalities of the plasma bradykinin-forming pathway and fibrinolysis

BACKGROUND

Hereditary angioedema (HAE) is typically the result of a deficiency of C1 inhibitor (C1-INH) with gene defects that lead to diminished plasma levels or the production of a dysfunctional protein. Replacement therapy with C1-INH has been shown to be effective in ameliorating episodes of swelling. We have reported elevated baseline levels of bradykinin, C4a, and plasmin-alpha2-antiplasmin complexes in the plasma of patients with HAE compared with the plasma of healthy controls. The production of factor XII fragment on in vitro activation of plasma with HAE has also been observed.

OBJECTIVE

To perform serial assessment of abnormalities of the bradykinin-forming pathway and fibrinolysis in patients with HAE after treatment of episodes of swelling with intravenous C1-INH.

METHODS

We obtained samples of plasma from 9 patients with HAE at a quiescent period (baseline), during an attack of swelling, and at 1, 4, and 12 hours after termination of an infusion of C1-INH. Factor XIIa, kallikrein, and plasmin were each measured by cleavage of synthetic substrates specific for each item.

RESULTS

Each enzyme was strikingly elevated at baseline compared with the levels in pooled healthy plasma, and there was a progressive decline of activity to normal for factor XIIa and plasmin. Kallikrein decreased in 7 of the 9 patients at 1 hour and then decreased in all patients. Bradykinin levels were elevated at the outset in all patients, increased prominently during an attack of swelling, decreased to baseline after 1 hour, and then decreased toward normal by 4 and 12 hours.

CONCLUSION

The plasma levels of factor XIIa, kallikrein, and bradykinin decreased when measured serially subsequent to the infusion of nanofiltered C1-INH.

Clinical review of hereditary angioedema: diagnosis and management

Hereditary angioedema (HAE) is caused by a deficiency in C1 esterase inhibitor and is characterized by sudden attacks of edema associated with discomfort and pain. The disease places patients at risk for disability and death if left untreated. Symptom severity and frequency can be extremely variable even among affected members of the same family. Attacks are not associated with inflammation or allergy, with most occurring secondary to trauma or stress. Swelling can affect any part of the body or multiple sites at once. Commonly affected areas include the extremities, genitalia, trunk, gastrointestinal tract, face, and larynx. Swelling typically worsens over 24 to 36 hours and resolves within 48 hours in less severe cases. Attacks result in 15,000 to 30,000 emergency department visits each year. Many of these emergency cases will undergo unnecessary surgeries or medical procedures due to misdiagnosis. The hallmarks of HAE--recurrent episodes of swelling without urticaria, a family history of HAE, first attack in childhood, and worsening at puberty--can be identified by a thorough family history, and the diagnosis can be confirmed by laboratory studies. Nevertheless, diagnosis may be delayed by 2 decades. We review available therapies and clinical characteristics that will both help clinicians diagnose HAE and distinguish among emergencies and nonemergency cases.

The effect of long-term danazol prophylaxis on liver function in hereditary angioedema-a longitudinal study

BACKGROUND

Danazol is a drug most widely used for the prophylaxis of hereditary angioedema resulting from the deficiency of the C1-inhibitor. Potential hepatotoxic or liver tumor-inducing side effects of long-term danazol prophylaxis have been investigated during the follow-up of hereditary angioedema patients.

METHODS

Characteristic parameters of liver function (including bilirubin, GOT, GPT, gammaGT, total protein, ALP, LDH), as well as findings of viral serology screens and abdominal ultrasonography-determined during years 0 and 5 of follow-up of patient groups taking/not taking danazol-have been reviewed and analyzed comparatively.

RESULTS

From a population of 126 hereditary angioedema patients, 46 subjects taking danazol and another 46 not taking danazol fulfilled the inclusion criteria. Longitudinal follow-up did not reveal any clinically relevant difference between the liver function parameters determined in years 0 and 5 in the two groups. Abdominal ultrasound did not detect neoplastic or other potentially treatment-related alterations of the liver parenchyma. There were no discontinuations of treatment during the study.

CONCLUSIONS

Our results clearly suggest that, administered at the lowest effective dose, danazol does not induce liver injury in hereditary angioedema patients.

Modulation of the proteolytic activity of the complement protease C1s by polyanions: implications for polyanion-mediated acceleration of interaction between C1s and SERPING1

The complement system plays crucial roles in the immune system, but incorrect regulation causes inflammation and targeting of self-tissue, leading to diseases such as systemic lupus erythematosus, rheumatoid arthritis and age-related macular degeneration. In vivo, the initiating complexes of the classical complement and lectin pathways are controlled by SERPING1 [(C1 inhibitor) serpin peptidase inhibitor, clade G, member 1], which inactivates the components C1s and MASP-2 (mannan-binding lectin serine peptidase 2). GAGs (glycosaminoglycan) and DXS (dextran sulfate) are able to significantly accelerate SERPING1-mediated inactivation of C1s, the key effector enzyme of the classical C1 complex, although the mechanism is poorly understood. In the present study we have shown that C1s can bind to DXS and heparin and that these polyanions enhanced C1s proteolytic activity at low concentrations and inhibited it at higher concentrations. The recent determination of the crystal structure of SERPING1 has given rise to the hypothesis that both the serpin (serine protease inhibitor)-polyanion and protease-polyanion interactions might be required to accelerate the association rate of SERPING1 and C1s. To determine what proportion of the acceleration was due to protease-polyanion interactions, a chimaeric mutant of alpha1-antitrypsin containing the P4-P1 residues from the SERPING1 RCL (reactive-centre loop) was produced. Like SERPING1, this molecule is able to effectively inhibit C1s, but is unable to bind polyanions. DXS exerted a biphasic effect on the association rate of C1s which correlated strongly with the effect of DXS on C1s proteolytic activity. Thus, whereas polyanions are able to bind C1s and modulate its activity, polyanion interactions with SERPING1 must also play a vital role in the mechanism by which these cofactors accelerate the C1s-SERPING1 reaction.

Current and emerging management options for hereditary angioedema in the US

Hereditary angioedema (HAE) is a rare disorder characterized by recurrent attacks of swelling that may involve multiple anatomical locations. In the majority of patients, it is caused by a functional or quantitative defect in the C1 inhibitor (C1-INH), which is an important regulator of the complement, fibrinolytic, kallikrein-kinin and coagulation systems. Standard treatments used for other types of angioedema are ineffective for HAE. Traditional therapies for HAE, including fresh frozen plasma, epsilon-aminocaproic acid and danazol, may be well tolerated and effective in some patients; however, there are limitations both in their safety and efficacy. Several novel therapies have completed phase III trials in the US, including: (i) plasma-derived C1-INH replacement therapies (Berinert P and Cinryze); (ii) a recombinant C1-INH replacement therapy (conestat alfa; Rhucin); (iii) a kallikrein inhibitor (ecallantide [DX-88]); and (iv) a bradykinin-2-receptor antagonist (icatibant). Both Berinert P and Cinryze are reported to have excellent efficacy and safety data from phase III trials. Currently, only Cinryze has been approved for prophylactic use in the US. US FDA approval for other novel agents to treat HAE and for the use of Cinryze in the treatment of acute attacks is pending.