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

Division of Pulmonary, Allergy, and Critical Care Medicine, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology (Impact Factor: 2.75). 03/2010; 104(3):211-4. DOI: 10.1016/j.anai.2009.12.004
Source: PubMed

ABSTRACT Hereditary angioedema (HAE) is an autosomal dominant disorder characterized by a deficiency of C1 esterase inhibitor (C1 INH) protein or function. Guidelines do not exist regarding diagnostic criteria or routine testing of family members of patients with HAE. Laboratory data for diagnosis include complement factor 4 level; C1 INH antigenic protein level, which is reduced in approximately 85% of patients with HAE; and C1 INH functional assay, which is considered an unreliable test in the United States secondary to inconsistent standardization of assays.
To assess the shortcomings of diagnosing HAE and to determine whether family members of patients with HAE are being adequately screened.
The top physician prescribers of danazol in the United States were screened via an Internet questionnaire focusing on the diagnosis and current management of HAE. To assess the patient perspective on HAE, affected individuals in the United States, the United Kingdom, France, Germany, and The Netherlands participated in the Web-based International Survey of Patient Experience of Hereditary Angioedema.
All 80 physicians who completed the survey were allergist or immunologists with a mean of 7 patients with C1 INH deficiency in their practices. Almost 84% of physician respondents used C1 INH level and function for diagnosis, and 63.8% used complement factor 4 levels. A total of 313 patients with HAE completed the survey. Respondents noted that only 48% of immediate family members and 26% of extended family members had been tested.
Guidelines could potentially alleviate delays in diagnosis and incorrect diagnoses and could lead to adequate screening of family members.

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    ABSTRACT: Background: No published data presently exist concerning hereditary angioedema (HAE) in Greece. The aim of this study was to present the results from patients recorded by the Greek Hereditary Angioedema Registry over the last 3 years (July 2010 to June 2013). Methods: A systematic recording of HAE cases was undertaken following a physician awareness campaign and confirmation of diagnosis. A questionnaire was also used for the assessment of key parameters of the patients' disease-specific quality of life. Results: One hundred and sixteen patients from 41 non-related families were recorded. There were 33 (80.5%) families with type I HAE, 7 (17%) with type II HAE and 1 (2.5%) with non-C1 inhibitor (C1-INH), non-FXII HAE. Two further non-C1-INH, non-FXII HAE sporadic cases were recorded. An investigation of non-symptomatic family members revealed another 6 asymptomatic individuals with C1-INH deficiency. The average delay in diagnosis was 16.5 years and the incidence of death in the families of patients was 1 for every 2 families. The use of newer therapeutic agents seems to fall significantly short of the existing needs. HAE was found to affect the quality of life slightly in 14%, greatly in 63% and significantly in 23% of the patients. Conclusion: Until recently, there has been a significant degree of underdiagnosis of HAE in Greece. Very low compliance with the provisions of the applicable international guidelines and consensus positions, with adverse consequences on the patients' quality of life, was also observed. The centralized model we used to uncover the patients could be effective in other countries presenting with comparable disease characteristics.
    International Archives of Allergy and Immunology 09/2014; 164(4):326-332. DOI:10.1159/000366276 · 2.43 Impact Factor
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    ABSTRACT: Hereditary angioedema (HAE) is a rare autosomal-dominant disease characterized by recurring attacks of nonpruritic, nonpitting edema caused by an inherited deficiency or dysfunction of C1 esterase inhibitor (C1 INH). Symptoms can present years before an accurate diagnosis is made. The objective of this study, the Angioedema Clinical Epidemiology Testing Initiative for the Study of Hereditary Angioedema, was to determine the prevalence and clinical manifestations of HAE in untested first-degree blood relatives of known patients with HAE. Patients with a confirmed diagnosis of HAE recruited first-degree relatives who had not been evaluated for HAE. Enrolled subjects underwent complement testing (C4, C1 INH antigen, and functional C1 INH). If the lab tests were abnormal, the enrolled subjects returned to the site for a follow-up visit and questionnaire. Overall, 31 patients with HAE and 46 first-degree relatives enrolled in the study. Of 46 enrolled relatives, 30 (65%) had lab test results that ruled out a diagnosis of HAE, two (4%) were categorized as "HAE not ruled out," and 14 (30%) were newly diagnosed with HAE. Of 14 newly diagnosed subjects, nine (64%) reported having experienced symptoms that may have been related to HAE, such as swelling in the throat, face, or extremities or abdominal pain. When reported, median age of symptom onset in these 14 subjects was nine years whereas newly diagnosed asymptomatic subjects had a median chronological age of six years. These 14 subjects reported a historic mean standard deviation rate of 2.51 (5.59) swelling episodes per month with a mean standard deviation duration of 1.6 (0.74) days. This study's findings reinforce the importance of testing family members of patients with HAE to detect this hereditary condition.
    Allergy and Asthma Proceedings 03/2015; 36(3). DOI:10.2500/aap.2015.36.3833 · 3.35 Impact Factor
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    ABSTRACT: Up to 93% of patients with hereditary angioedema (HAE) experience recurrent abdominal pain. Many of these patients, who often present to emergency departments, primary care physicians, general surgeons, or gastroenterologists, are misdiagnosed for years and undergo unnecessary testing and surgical procedures. Making the diagnosis of HAE can be challenging because symptoms and attack locations are often inconsistent from one episode to the next. Abdominal attacks are common and can occur without other attack locations. An early, accurate diagnosis is central to managing HAE. Unexplained abdominal pain, particularly when accompanied by swelling of the face and extremities, suggests the diagnosis of HAE. A family history and radiologic imaging demonstrating edematous bowel also support an HAE diagnosis. Once HAE is suspected, C4 and C1 esterase inhibitor (C1-INH) laboratory studies are usually diagnostic. Patients with HAE may benefit from recently approved specific treatments, including plasma-derived C1-INH or recombinant C1-INH, a bradykinin B2-receptor antagonist, or a kallikrein inhibitor as first-line therapy and solvent/detergent-treated or fresh frozen plasma as second-line therapy for acute episodes. Short-term or long-term prophylaxis with nanofiltered C1-INH or attenuated androgens will prevent or reduce the frequency and severity of episodes. Gastroenterologists can play a critical role in identifying and treating patients with HAE, and should have a high index of suspicion when encountering patients with recurrent, unexplained bouts of abdominal pain. Given the high rate of abdominal attacks in HAE, it is important for gastroenterologists to appropriately diagnose and promptly recognize and treat HAE, or refer patients with HAE to an allergist.
    Clinical and Experimental Gastroenterology 01/2014; 7:435-445. DOI:10.2147/CEG.S50465