Angioedema

Case Report: VV-ECMO as a bridge to recovery from ACE inhibitor induced post-obstructive negative pressure pulmonary edema

The indications for extracorporeal membrane oxygenation (ECMO) are becoming increasingly widespread nowadays. This case report describes the unique presentation of an adult patient with a combination of two rare complications: life-threatening angioedema caused by angiotensin-converting enzyme inhibitors (ACEi) and subsequent post-obstructive negative pressure pulmonary edema (NPPE). In this case, worsening angioedema that was unresponsive to medication led to severe airway obstruction and near-fatal acute respiratory syndrome due to NPPE. The worsening clinical course required a multidisciplinary approach and immediate initiation of extracorporeal membrane oxygenation (VV-ECMO). The literature reports that most NPPE cases resolve with oxygenation. However, in our case, the NPPE was refractory to mechanical ventilatory support, and we had to initiate VV-ECMO to prevent the patient from going into cardiac arrest due to severe hypoxia. This case underscores the critical role of VV-ECMO as a bridge to recovery from severe NPPE. It also highlights the need to raise clinicians' awareness of the potential life-threatening side effects of the commonly used antihypertensive drug perindopril.

High-Throughput Screening for Prescribing Cascades Among Real-World Angiotensin-Converting Enzyme Inhibitor Initiators

PURPOSE

Angiotensin-converting enzyme inhibitors (ACEIs) are commonly prescribed, but their adverse effects may prompt new drug prescription(s), known as prescribing cascades (PCs). We aimed to identify potential ACEI-induced PCs using high-throughput sequence symmetry analysis.

METHODS

Using claims data from a national sample of Medicare beneficiaries (2011-2020), we identified new ACEI users aged ≥ 66 years with continuous enrollment ≥ 360 days before and ≥ 180 days after ACEI initiation. We screened for initiation of 446 other (non-antihypertensive) "marker" drug classes within ±90 days of ACEI initiation, generating sequence ratios (SRs) reflecting proportions of ACEI users starting the marker class after versus before ACEI initiation. Adjusted SRs (aSRs) accounted for prescribing trends over time. For significant aSRs, we calculated the naturalistic number needed to harm (NNTH), and significant signals underwent clinical review for plausibility.

RESULTS

We identified 308 579 ACEI initiators (mean age 76.1 ± 7.5 years; 59.6% female; 88.6% with hypertension). Of 446 marker classes evaluated, 81 signals were significant, and 42 (52%) classified as potential PCs after clinical review. The strongest signals ranked by lowest NNTH included corticosteroids (NNTH 313; 95% CI, 262-392) and serotonin type 3 (5-HT3) antagonists (NNTH 496; 95% CI, 392-689); the strongest signals ranked by highest aSR included sympathomimetics (aSR, 1.97; 95% CI, 1.10-3.53) and other antianemic preparations (aSR, 1.87; 95% CI, 1.31-2.67).

CONCLUSION

Identified prescribing cascade signals were indicative of known and possibly underrecognized ACEI adverse events in this Medicare cohort. The findings are hypothesis-generating and require further investigation to determine the extent and impact of the identified PCs on health outcomes.

Facial Edema After Nuclear Stress Test

Angioedema involves fluid accumulation into the interstitial spaces of the dermis, subcutaneous tissue, and mucosal surfaces. While usually benign and self-limited, angioedema can lead to laryngeal edema, a life-threatening condition. The most common causes are histamine-mediated allergic reactions. However, angioedema can also be mediated by bradykinin. Bradykinin-mediated angioedema can occur in the setting of hereditary deficiency of C1q esterase and after exposure to several medications. Drug-induced angioedema is most commonly a secondary complication of non-steroidal anti-inflammatory drug (NSAID) or sulfa drug use. All providers must be aware of the potential side effects of the medications they use or prescribe. We present a case of angioedema resulting from the use of technetium-99m sestamibi tracer injection during an adenosine nuclear stress test.

Late-Onset Angioedema With Olanzapine in a Tertiary Hospital

A medical condition known as angioedema is characterized by sudden swelling of the mucosa, subcutaneous tissue, dermis, and submucosal tissues. If airway obstruction results in respiratory distress, this condition may be fatal. Histamine, bradykinin, and leukotrienes are just a few of the complex chemotactic mediators that play a role in the pathophysiology of angioedema and can lead to fluid buildup in deeper skin layers. Many things, such as medication side effects, genetic disorders, and allergic reactions, can cause angioedema. Olanzapine, an atypical antipsychotic mainly used to treat a few mental disorders, is one notable drug linked to angioedema. Angioedema is a documented side effect of olanzapine, albeit rare. Although the exact mechanism by which olanzapine causes angioedema is unknown, immunological-mediated or idiosyncratic reactions are thought to be involved. This study aims to review the current literature on the association between olanzapine and angioedema, including potential mechanisms of action and implications for clinical management. The possible risk factors, presentation, diagnosis, and treatment options for olanzapine-induced angioedema will also be discussed.

Mast cell degranulation and bradykinin-induced angioedema - searching for the missing link

Initiation of the bradykinin generation cascade is responsible for the occurrence of attacks in some types of angioedema without wheals. Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1-INH) is one such clinical entity. In this paper, we explore the existing evidence that mast cells (MCs) degranulation may contribute to the activation of the kallikrein-kinin system cascade, followed by bradykinin formation and angioedema. We present the multidirectional effects of MC-derived heparin and other polyanions on the major components of the kinin-kallikrein system, particularly on the factor XII activation. Although, bradykinin- and histamine-mediated symptoms are distinct clinical phenomena, they share some common features, such as some similar triggers and a predilection to occur at sites where mast cells reside, namely the skin and mucous membranes. In addition, recent observations indicate a high incidence of hypersensitivity reactions associated with MC degranulation in the HAE-C1-INH patient population. However, not all of these can be explained by IgE-dependent mechanisms. Mast cell-related G protein-coupled receptor-X2 (MRGPRX2), which has recently attracted scientific interest, may be involved in the activation of MCs through a different pathway. Therefore, we reviewed MRGPRX2 ligands that HAE-C1-INH patients may be exposed to in their daily lives and that may affect MCs degranulation. We also discussed the known inter- and intra-individual variability in the course of HAE-C1-INH in relation to factors responsible for possible variability in the strength of the response to MRGPRX2 receptor stimulation. The above issues raise several questions for future research. It is not known to what extent a prophylactic or therapeutic intervention targeting the pathways of one mechanism (mast cell degranulation) may affect the other (bradykinin production), or whether the number of mast cells at a specific body site and their reactivity to triggers such as pressure, allergens or MRGPRX2 agonists may influence the occurrence of HAE-C1-INH attacks at that site.

Airway Involvement and Intervention in Non-ACE-Inhibitor-Induced Angioedema

OBJECTIVES

Characterize the presentation of patients with non-angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema and determine risk factors associated with patient disposition and possible need for airway intervention.

METHODS

The medical records of adult patients in the Emergency Department (ED) and diagnosed with non-ACEI-induced angioedema over 4.5 years were included. Demographics, vital signs, etiology, timeline, presenting symptoms, physical exam including flexible laryngoscopy, medical management, and disposition were examined. Statistical analyses were conducted using SPSS V 23.0 software calculating and comparing means, standard deviations, medians, and correlation of categorical and ordinate variables.

RESULTS

A total of 181 patients with non-ACEI-induced angioedema were evaluated with flexible laryngoscopy by otolaryngology. Notably, 11 patients (6.1%) required airway intervention and were successfully intubated. Statistically significant factors (p ≤ 0.05) associated with airway intervention included the diastolic blood pressure (DBP) and mean arterial pressure (MAP) (p = 0.006 and 0.01 respectively), symptoms of dysphonia (p = 0.018), the presence of oropharyngeal, supraglottic, and hypopharyngeal edema (p ≤ 0.001 for each site), and the number of edematous anatomic subsites documented on physical exam (p < 0.001). Other patient demographics, prior history of angioedema, heart rate, systolic blood pressure, symptom onset, number of symptoms at presentation, and medication administered in the ED did not correlate with airway intervention.

CONCLUSION

Dysphonia, DBP, MAP, anatomic location of edema and edema in multiple sites are associated with airway intervention and a higher level of care in non-ACEI-induced angioedema and can be useful in risk assessment in patient management.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2282-2287, 2024.

The bradykinin-forming cascade in anaphylaxis and ACE-inhibitor induced angioedema/airway obstruction

Anaphylaxis is a potentially life-threatening multi-system allergic reaction to a biological trigger resulting in the release of potent inflammatory mediators from mast cells and basophils and causing symptoms in at least two organ systems that generally include skin, lungs, heart, or gastrointestinal tract in any combination. One exception is profound hypotension as an isolated symptom. There are two types of triggers of anaphylaxis: immunologic and non-Immunologic. Immunologic anaphylaxis is initiated when a foreign antigen directly binds to IgE expressed on mast cells or basophils and induces the release of histamine and other inflammatory substances resulting in vasodilation, vascular leakage, decreased peripheral vascular resistance, and heart muscle depression. If left untreated, death by shock (profound hypotension) or asphyxiation (airway obstruction) can occur. The non-immunologic pathway, on the other hand, can be initiated in many ways. A foreign substance can directly bind to receptors of mast cells and basophils leading to degranulation. There can be immune complex activation of the classical complement cascade with the release of anaphylatoxins C3a and C5a with subsequent recruitment of mast cells and basophils. Finally, hyperosmolar contrast agents can cause blood cell lysis, enzyme release, and complement activation, resulting in anaphylactoid (anaphylactic-like) symptoms. In this report we emphasize the recruitment of the bradykinin-forming cascade in mast cell dependent anaphylactic reactions as a potential mediator of severe hypotension, or airway compromise (asthma, laryngeal edema). We also consider airway obstruction due to inhibition of angiotensin converting enzyme with a diminished rate of endogenous bradykinin metabolism, leading not only to laryngeal edema, but massive tongue swelling with aspiration of secretions.

The analysis of the effect of the COVID-19 pandemic on patients with hereditary angioedema type I and type II

Due to the similarity between the pathomechanism of SARS-CoV-2 infections and hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE), a possibility emerged that C1-INH-HAE may worsen the course of the infection, or that the infection may influence the severity of angioedema (HAE) attacks in C1-INH-HAE patients. Our study aimed to evaluate the effects of the COVID-19 pandemic on the quality of life (QoL) of Hungarian C1-INH-HAE patients, and to survey the acute course of the infection, post COVID symptoms (PCS), vaccination coverage and the side effects of vaccines in this patient population. 93 patients completed our questionnaire between 1st July 2021 and 31st October 2021. In this same period and between March 2019 and March 2020, 63 patients completed the angioedema quality of life questionnaire (AE-QoL). Out of those patients infected with SARS-CoV-2 in the examined period (18/93 patients; 19%), 5% required hospitalization, 28% experienced HAE attacks in the acute phase of the infection, and 44% experienced PCS. A total number of 142 doses of vaccines were administered to the patients. Serious vaccine reactions did not occur in any case, 4 (5%) out of the 73 vaccinated patients experienced HAE attacks. No significant difference (p = 0.59) was found in the median of the AE-QoL total score, or in the number of HAE attacks prior and during the pandemic. Based on our study, HAE patients did not experience more serious SARS-CoV-2 infection, and it did not aggravate the course of HAE either. Changes in the QoL were not significant, and vaccines were safe in HAE patients.

Acute Lower Lip Swelling: A Mere Anaphylactic Reaction or a Rare Abscess Location?

An abscess is a collection of pus secondary to an immune response to a pathogen. It can occur anywhere in the body, with the skin as the most common organ involved. A lip abscess is a rare condition. Generally, it may be due to an infective agent such as a virus or bacteria entering through a skin wound, or through hematogenous spread when there is a severe underlying condition such as a general condition disorder or immunodeficiency. It requires hypervigilance during the examination and throughout the treatment course with intravenous antibiotic therapy and urgent surgical drainage, as it may cause significant complications regarding localization, lymphovascular drainage, and ultimate spread. Persistent abscess, necrotic tissue, or cavitated lesions are worrisome and it is important to rule out immunosuppression or a methicillin-resistant staphylococcus. In this case, a 22-year-old male patient with a unilateral lip abscess, misdiagnosed as an allergic food reaction, responded well to external drainage and antibiotic therapy.

Assessment of the number of mast cells in the soft palate of dogs affected by brachycephalic obstructive airway syndrome

BACKGROUND

Oedema is described in the soft palate of dogs affected by brachycephalic obstructive airway syndrome (BOAS). Activated mast cells (MCs) release vasoactive mediators that temporarily increase vascular permeability.

METHODS

Data and caudal soft palate tissue were prospectively collected from a population of dogs undergoing surgical management of BOAS and a control group of greyhound cadavers with no previous history of respiratory signs. Histological assessment was performed to quantify the number of MCs within the lamina propria of each group.

RESULTS

The mean number of MCs in the BOAS group (53 MCs/10 400× high-power fields [HPF]; standard deviation [SD] = 23) was significantly greater than that in the greyhound group (24 MCs/10 400×HPF; SD = 10).

LIMITATIONS

The small size of the control group and the heterogeneous nature of the dogs in the BOAS group limit the generalisability of the findings. The use of different surgical techniques in the BOAS group may have also affected the degree of inflammation present within the samples. The cohort was not screened for concurrent disease processes that could potentially increase the number of circulating MCs.

CONCLUSION

This study demonstrated a statistically significant difference between the numbers of MCs in the soft palate of brachycephalic dogs with clinically significant BOAS and the greyhound control group.

Content validation and psychometric evaluation of the Angioedema Quality of Life Questionnaire for hereditary angioedema

BACKGROUND

There is considerable burden of illness in hereditary angioedema (HAE). However, instruments to assess health-related quality of life (HRQoL) in HAE are limited. The Angioedema Quality of Life Questionnaire (AE-QoL) was developed to measure HRQoL in patients with recurrent angioedema; the validity of the AE-QoL in patients with HAE is described.

METHODS

To identify disease-related experiences with a focus on the impact of HAE on HRQoL, interviews were conducted with a group of clinician experts and patients with HAE from Canada, France, Germany, Spain, the United Kingdom, and the United States, along with a targeted literature review. Concepts were mapped to the AE-QoL to assess item relevance, interpretation, and conceptual coverage. Cognitive interviews assessed item clarity and relevance. A psychometric validation was performed using data from a phase 3 trial.

RESULTS

Interviews were conducted with seven clinicians and 40 adult patients. Patients reported 35 unique impacts of HAE on their lives, the most frequent being on work/school, social relationships, physical activities, and emotions, particularly fear/worrying and anxiety. Saturation for these impacts was reached, and all concepts covered in the AE-QoL were reported during the interviews. Patients agreed that the questionnaire items and response options were clear and relevant, and the 4-week recall period was appropriate. The psychometric validation included data from 64 patients. For AE-QoL total scores, excellent internal consistency (Cronbach's alpha > 0.90), test-retest reliability (intraclass coefficient > 0.80), convergent validity with the Sheehan Disability Scale (r = 0.663), divergent validity with the EQ-5D-5L index (r = 0.292) and EQ-VAS (r = 0.337), and known-groups validity (p < 0.0001; ɳ2 = 0.56) were demonstrated.

CONCLUSIONS

Qualitative and psychometric analyses showed that the AE-QoL is a reliable and valid instrument for measuring HRQoL in adult patients with HAE from six countries.

[Hereditary angioedema and its new treatments: An update]

Hereditary angioedema, with or without deficient C1 inhibitor level or function, is a rare disease characterized by recurrent attacks of noninflammatory subcutaneous and/or submucosal edema. It may be life-threatening and substantially affects quality of life. Attacks may be spontaneous or induced, in a setting of emotional stress, by infections or physical trauma, in particular. As the key mediator is bradykinin, this angioedema does not respond to the usual treatments of mast cell-mediated angioedema (antihistamines, corticosteroids, adrenaline), which is much more frequent. Therapeutic management of hereditary angioedema first consists in treating severe attacks with a selective B2 bradykinin receptor antagonist or a C1 inhibitor concentrate. The latter or an attenuated androgen (danazol) can be used for short-term prophylaxis. Therapeutic solutions conventionally proposed for long-term prophylaxis (danazol, antifibrinolytics [tranexamic acid], C1 inhibitor concentrate) vary in efficacy and/or pose problems of safety or ease of use. Kallikrein inhibitors (subcutaneous lanadelumab, oral berotralstat) recently made available as disease-modifying treatment constitute an important advance in long-term prophylaxis of hereditary angioedema attacks. The advent of these new drugs is accompanied by a new ambition for patients: optimize control of the disease and thereby minimize its impact on quality of life.

A comparative study of chronic spontaneous urticaria and chronic mast cell mediated angioedema

Background: Mast cell-mediated angioedema (MC-AE) is considered a form of chronic spontaneous urticaria (CSU). Objective: To investigate the clinical and laboratory features that distinguish MC-AE from antihistamine-responsive CSU (CSU), and antihistamine-resistant CSU (R-CSU) with and without concomitant AE. Methods: A retrospective observational study using the electronic patient record data base of patients with MC-AE, CSU, R-CSU, and sex- and age-matched control group (control), with a case-control ratio of 1:2. Results: A total of 986 subjects in the CSU group, 148 in the R-CSU group, 64 in the MC-AE group, and 1198 in the control group were compared. The R-CSU group without AE was characterized by lower total IgE levels (118.5 ± 84.7 IU/mL) and higher High sensitivity-C reactive protein (hs-CRP) levels (138.9 ± 94.2 IU/mL, p = 0.027; and 7.4 ± 6.9 mg/L versus 5.1 ± 6.8 mg/L, p = 0.001) than the CSU without AE group. The R-CSU group with AE was characterized by lower total IgE levels (112.1 ± 81.3 IU/mL) than the CSU group with AE (141.7 ± 89.5 IU/mL; p < 0.001), higher hs-CRP levels (7.1 ± 6.1 mg/L versus 4.7 ± 5.9 mg/L; p < 0.001). There were fewer female subjects in the MC-AE group (31 [48.4%]) than in the CSU with AE and in the R-CSU with AE 223 (67.8%) and 18 (66.7%), respectively; p = 0.012). MC-AE group was characterized by less eyelid/perioral/facial involvement and more limb involvement than in the CSU with AE and R-CSU with AE groups (p < 0.001). Conclusion: Low IgE in MC-AE and higher IgE in CSU may signify two distinct types of immune dysregulation. Due to clinical and laboratory differences between MC-AE and CSU, we suggest questioning the assumption that MC-AE is a form of CSU.

Geriatric Pharmacotherapy Case Series: Recurrent Angioedema Following Discontinuation of ACE Inhibitor Therapy

Introduction Angiotensin-converting enzyme inhibitors (ACEIs) are first-line pharmaceutical agents in common chronic conditions such as hypertension and heart failure with reduced ejection fraction. When angioedema occurs, if secondary to ACEIs, discontinuation of the ACEI is necessary to mitigate the risk of recurrent angioedema. While angioedema is a well-known adverse effect of ACEIs, it is not well-known that angioedema may recur even after ACEI discontinuation. Additionally, only few reports in the literature describe this phenomenon. This case describes an older man with a history of chronic obstructive pulmonary disease, hypothyroidism, diabetes mellitus, hypertension, and heart failure who presented from an assisted living facility with recurrent angioedema 12 days after an initial episode of angioedema where his ACEI therapy (enalapril) was discontinued. Assessment Empiric methylprednisolone, diphenhydramine, intramuscular epinephrine, intravenous C1 esterase inhibitor Berinert®, and two units of fresh frozen plasma was given in the emergency department. The patient was monitored in the intensive care unit because of mild airway compromise but did not require invasive airway protection. Serum C4 level was normal, ruling out hereditary angioedema. Outcome Patient was discharged after five days in stable condition with resolution of symptoms. Conclusion ACEIs are the most common cause of drug-induced angioedema in the United States. Angioedema is self-limiting swelling that requires close airway monitoring. While health professionals recognize the risk for angioedema with active ACEI use, it is not well known that the risk of angioedema may occur for months following cessation of ACEI therapy. Increased awareness of delayed ACEI-induced angioedema following ACEI discontinuation is important for both providers and pharmacists to provide appropriate diagnosis and monitoring. Improved awareness would also allow patients with a history of ACEI-induced angioedema to be cognizant of the potential for recurrence following drug discontinuation.

Isolated Angioedema: A Review of Classification and Update on Management

OBJECTIVE

The purpose of this article is to review the various types of angioedema including diagnosis and treatment.

DATA SOURCES

PubMed search of articles in the English language various types of angioedema STUDY SELECTION: Articles on the subject matter were selected and reviewed.

RESULTS

Herein, a case based approach is presented for discussing the major types of angioedema including: hereditary angioedema (HAE) TypesI/II and normal complement, acquired angioedema, Angiotensin converting enzyme (ACE) induced angioedema, as well as histaminergic and non-histaminergic angioedema. Emerging treatments of HAE including targets of pre-kalikrein, DNA vector technology replacing C1INH protein, and CRIPSR technology targeting PKK among many others are explored. In addition, other causes as well as mimickers of angioedema are briefly reviewed. Finally, a novel algorithm is proposed to help guide the treating physician through the work up and management of patients with suspected idiopathic angioedema unresponsive to conventional therapy with antihistamines.

CONCLUSION

Over the years, many strides have been made in both understanding the pathophysiology of various types of angioedema as well as expansion of treatment options. It is important for clinicians to be aware of current and emerging treatment options. We provide a novel practical algorithm to guide clinicians in challenging cases of idiopathic angioedema refractory to antihistamines.

Clinical Manifestations and Genetic Influences in Sulfonamide-Induced Hypersensitivity

Drug hypersensitivity is an inflammatory or immune reaction induced by drugs. It can be fatal if not appropriately treated and cause the risk of long-term complications. Sulfonamides are classified as antimicrobial drugs with a broad spectrum effective for gram-positive and gram-negative bacteria. This antibacterial agent works by competitively inhibiting folic acid synthesis, which prevents the growth and proliferation of microorganisms. In its use as antibiotics, sulfonamides can also cause adverse reactions in specific individuals. It has been widely reported that sulfonamide antimicrobials cause hypersensitivity reactions mediated by IgE or T cells. This review identifies symptoms or signs that can appear, as well as genes associated with sulfonamide hypersensitivity reactions, as sulfonamide may cause hypersensitivity in the form of uveitis, skin rash, Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), parotitis, angioedema, drug reaction with eosinophilia and systemic symptoms (DRESS), and pruritus. In addition, several genes were found to be associated with sulfonamide hypersensitivity, including HLA-A29, HLA-B12, HLA-DR7, HLA-B44, and HLA A*11:01.

Pharmacovigilance study of the association between dipeptidyl peptidase-4 inhibitors and angioedema using the FDA Adverse Event Reporting System (FAERS)

Dipeptidyl peptidase-4 (DPP-4) plays a minor role in degrading vasoactive peptides that cause angioedema when angiotensin-converting enzyme (ACE) is present and fully functional. This study investigated the association between DPP-4 inhibitors (DPP-4Is) and angioedema, including cases where the concomitant use of ACE inhibitors (ACEIs) was absent. We obtained data from the US Food and Drug Administration Adverse Event Reporting System and performed a disproportionality analysis, using the reporting odds ratio (ROR) and information component (IC) for signal detection in patients aged ≥ 40 years, stratified by age group and sex. No signal was detected for DPP-4Is when the entire dataset was analyzed. However, a signal was detected for the entire female subset group, the three stratified female groups aged ≥ 60 years, and males in their 40 s. After excluding the data of concomitant ACEI users, most ROR and IC values were lower and significant only for females in their 60 s and males aged ≥ 80 years. Regarding individual DPP-4Is signals, those detected for saxagliptin and sitagliptin in some age groups disappeared after excluding the data of ACEI users. Notably, linagliptin was the only DPP-4I where signals were detected in most female groups, regardless of age and without concomitant ACEI use. Our findings suggest that some DPP-4Is were associated with a higher reporting of angioedema as per age and sex, even in the absence of concomitant ACEI use.

The international WAO/EAACI guideline for the management of hereditary angioedema - The 2021 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2), by providing guidance on common and important clinical issues, such as: 1) How should HAE be diagnosed? 2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? 3) What are the goals of treatment? 4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast feeding women? 5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2021 revision and update

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The First Occurrence of Angioedema After Discontinuation of Angiotensin-Converting Enzyme Inhibitor

Angioedema is one of the dreaded side effects of angiotensin-converting enzyme (ACE) inhibitors. It has been well established in the literature and the timing of onset is variable from months to years after initiation of therapy. Patients remain at risk of recurrence of angioedema even after discontinuation of the drug if they developed it once while on the drug. While only recurrences of ACE inhibitor-induced angioedema are described in the literature, our patient did not develop angioedema while being on the drug and had the first occurrence of angioedema one month after the medication was discontinued. We argue that since our patient did report an ACE inhibitor-related dry cough, this case emphasizes the strength of the relation between the two common side effects of the ACE inhibitors. This favors that among the risk factors that predispose individuals to develop angioedema, ACE inhibitor-associated cough is a major one. Although the mechanism of ACE inhibitor-related cough is poorly understood, bradykinin seems to be the common culprit mediator for these two side effects. Hence, clinicians need to be aware of this potential threat and be cautioned when they witness an ACE inhibitor-related cough.

A Case Report of Delayed Post-operative Angioedema Associated With Angiotensin-Converting Enzyme Inhibitor Use

Angiotensin-converting enzyme inhibitors are known to precipitate angioedema. Drug-induced angioedema is rare in the perioperative setting. Even fewer cases described hours following a minor procedure. In this case report, we present a 45-year-old female who developed drug-induced angioedema hours following an obstetric procedure.

Angioedema with severe acute abdominal pain: Think of hereditary angioedema

Angioedema can be either mast cell-(histamine-)mediated or bradykinin-mediated. Treatment approaches for the two types are very different, making differential diagnosis critical. Severe acute abdominal pain caused by intestinal angioedema is commonly misdiagnosed, especially when associated with bradykinin-mediated angioedema. After describing a typical clinical scenario and diagnostic journey of a patient with recurrent, undiagnosed abdominal pain due to hereditary angioedema (HAE), a rare variant of bradykinin-mediated angioedema, we delve into the classification and differential diagnosis of the various types of angioedema and provide an overview of appropriate management with an emphasis on the bradykinin-mediated types. Bradykinin-induced angioedema may be inherited or acquired and is infrequent compared to mast cell-mediated angioedema. HAE is a rare disease characterized by recurrent attacks of non-urticarial, nonpruritic edema usually affecting the face, respiratory tract, extremities, gastrointestinal tract, and genitalia. Unlike mast cell-mediated angioedema, painful abdominal symptoms are prevalent in bradykinin-mediated angioedema and are sometimes the only manifestation of an attack, increasing the likelihood of initial misdiagnosis as appendicitis or other forms of acute abdomen. It is important for gastroenterologists to be vigilant for the possibility of angioedema pathology in patients presenting with undiagnosed, recurrent, abdominal symptoms to facilitate accurate diagnosis and effective treatment.

Pathophysiology of Hereditary Angioedema (HAE) Beyond the SERPING1 Gene

Hereditary Angioedema (HAE) is an autosomal dominant disorder characterized clinically by recurrent episodes of swelling involving subcutaneous tissues, gastrointestinal tract, and oro-pharyngeal area. Gene mutations are the most common genetic cause of HAE and observed in more than 90% of patients. More than 700 mutation variants have been described so far. Patients with angioedema who have no mutations in the gene for C1-INH and normal levels and activity of this inhibitor are labelled: normal C1 inhibitor HAE. These include genetic mutations in factor 12 gene, plasminogen gene, angiopoietin gene, kininogen 1, and myoferlin genes. The clinical manifestations of patients with these mutations are similar to with patients with C1-INH gene mutations. However, a later age of onset, oro-pharyngeal involvement, and higher female preponderance have been reported in these rare subtypes of hereditary angioedema. With the advent and increased accessibility of whole-exome sequencing, it is expected that new genetic defects and novel pathophysiological pathways will be identified in families with HAE of unknown cause or normal C1-INH angioedema. This review covers some of the recent advances in the field of HAE. The review focuses on pathophysiology of HAE beyond the well-known C1-INH deficiency phenotypes, including various biomarkers that can serve the diagnosis and management of these rare disorders.

Clinical Practice Statement: What is the Emergency Department Management of Patients with Angioedema Secondary to an ACE-Inhibitor?

BACKGROUND

Angioedema is a complication that has been reported in up to 1.0% of individuals taking angiotensin-converting enzyme inhibitors (ACE-Is). Importantly, the onset of angioedema can occur anywhere from hours to several years after initiation of therapy with ACE-Is. Although most cases of ACE-I-induced angioedema (ACE-I-AE) are self-limiting, a major clinical concern is development of airway compromise, which can potentially require emergent airway management. The underlying pathophysiology of ACE-I-AE is incompletely understood, but is considered to be due in large part to excess bradykinin. Numerous medications have been proposed for the treatment of ACE-I-AE. This article is an update to the 2011 Clinical Practice Committee (CPC) statement from the American Academy of Emergency Medicine.

METHODS

A literature search in PubMed was performed with search terms angioedema and ACE inhibitors from August 1, 2012 to May 13, 2019. Following CPC guidelines, articles written in English were identified and then underwent a structured review for evaluation.

RESULTS

The search parameters resulted in 323 articles. The abstracts of these articles were assessed independently by the reviewers, who determined there were 63 articles that were specific to ACE-I-AE, of which 46 were deemed appropriate for grading in the final focused review.

CONCLUSIONS

The primary focus for the treatment of ACE-I-AE is airway management. In the absence of high-quality evidence, no specific medication therapy is recommended for its treatment. If, however, the treating physician feels the patient's presentation is more typical of an acute allergic reaction or anaphylaxis, it may be appropriate to treat for those conditions. Any patient with suspected ACE-I-AE should immediately discontinue that medication.

Recognition, Evaluation, and Management of Pediatric Hereditary Angioedema

ABSTRACT

Hereditary angioedema (HAE) is a rare, often underrecognized genetic disorder caused by either a C1 esterase inhibitor deficiency (type 1) or mutation (type 2). This leads to overproduction of bradykinin resulting in vasodilation, vascular leakage, and transient nonpitting angioedema occurring most frequently in the face, neck, upper airway, abdomen, and/or extremities. Involvement of the tongue and laryngopharynx has been associated with asphyxiation and death. Hereditary angioedema is an autosomal-dominant condition; therefore, there is a 50% chance an offspring will inherit this disorder. Any patient presenting with isolated angioedema should be screened with a C4 measurement, as 25% of cases have no family history of HAE. All patients with HAE will have a functional deficiency of C1 esterase inhibitor. Contributors that delay the diagnosis of HAE include recognition delay by clinicians who confuse this condition with histaminergic angioedema, the disease's varied presentations, and limitations to timely testing. Pediatric emergency clinicians should be knowledgeable about how to distinguish between bradykinin- and histamine-mediated angioedema, as there are significant differences in the diagnostic testing, treatment, and clinical response between these 2 different conditions. Evidence indicates that early diagnosis and treatment of HAE reduces morbidity and mortality. Clinician recognition of the mechanistically different problems will ensure patients are appropriately referred to an expert for outpatient management.

Thrombin in the Activation of the Fluid Contact Phase in Patients with Hereditary Angioedema Carrying the F12 P.Thr309Lys Variant

Hereditary angioedema due to pathogenic FXII variants (HAE-FXII) is a rare dominant disease caused by increased activation of the plasma contact system. The most prevalent HAE-FXII variant, c.1032C > A p.Thr309Lys (FXII^309Lys), results in a smaller FXII protein with increased sensitivity to fluid-phase activation by poorly understood mechanisms. We aimed to investigate the functionality of the FXII^309Lys variant in 33 HAE-FXII patients, 25 healthy controls and 46 patients with congenital disorders of glycosylation (CDG). Activation of the plasma contact system was assessed by western blot and amidolytic assay in basal conditions or after treatment with either artificial or physiological activators. Recombinant wild-type and FXII^309Lys variants were expressed in S2 insect (Drosophila) cells. Amidolytic and fibrin generation assays were performed in fresh plasma samples. FXII^309Lys samples exhibited an increased electrophoretic mobility comparable with N-glycan-deficient FXII from CDG patients and asialo-FXII generated by neuraminidase treatment. They presented increased sensitivity to activation by dextran sulphate and silica which resulted in the generation of an aberrant 37-kDa heavy chain. We did not observe increased susceptibility of FXII^309Lys to proteolysis by exogenous or tPA-generated plasmin. However, both exogenous and endogenous thrombin cleaved the FXII^309Lys variant, releasing a 37-kDa fragment and resulting in enhanced proteolytic activation on the fluid phase. This model supports a sequential proteolytic activation process involving thrombin priming of FXII^309Lys, followed by kallikrein cleavage and generation of active βFXIIa. The present results and the observation that angioedema episodes in HAE-FXII patients occur predominantly during hypercoagulable situations suggest a key role for thrombin.

Biomarkers in Hereditary Angioedema

A biomarker is a defined characteristic measured as an indicator of normal, biologic, pathogenic processes, or biological responses to an exposure or intervention. Diagnostic biomarkers are used to detect a disease or a subtype of a disease; monitoring biomarkers are measured serially to assess a medical condition; response biomarkers are used to check biologic response following a medical intervention; predictive biomarkers are used to identify patients who are more likely to respond to a medical intervention; and prognostic biomarkers are used to assess the future likelihood of a clinical event. Although biomarkers have been extensively investigated and validated in many diseases and pathologies, very few are currently useful for the diagnosis, evaluation of disease activity, and treatment of hereditary angioedema (HAE). Pathophysiologic pathways involved in HAE reveal a plethora of molecules from the complement, coagulation, and fibrinolysis systems or from the vascular endothelium, which may serve as biomarkers. The most promising candidates, together with their laboratory readout systems, should be evaluated with regard to their analytical and clinical validity and utility. To be highly specific, such biomarkers should be linked to the pathomechanisms of HAE, particularly the bradykinin-generating cascade. Additionally, major advances in high-throughput omics-based technologies may facilitate the discovery of new candidate biomarkers in the future. This review will cover the existing as well as future potential biomarkers that will support the diagnosis, monitor disease activity, and can be used to assess the efficacy of new avenues of therapy of HAE and other forms of angioedema.

The Role of the Plasminogen Activation System in Angioedema: Novel Insights on the Pathogenesis

The main physiological functions of plasmin, the active form of its proenzyme plasminogen, are blood clot fibrinolysis and restoration of normal blood flow. The plasminogen activation (PA) system includes urokinase-type plasminogen activator (uPA), tissue-type PA (tPA), and two types of plasminogen activator inhibitors (PAI-1 and PAI-2). In addition to the regulation of fibrinolysis, the PA system plays an important role in other biological processes, which include degradation of extracellular matrix such as embryogenesis, cell migration, tissue remodeling, wound healing, angiogenesis, inflammation, and immune response. Recently, the link between PA system and angioedema has been a subject of scientific debate. Angioedema is defined as localized and self-limiting edema of subcutaneous and submucosal tissues, mediated by bradykinin and mast cell mediators. Different forms of angioedema are linked to uncontrolled activation of coagulation and fibrinolysis systems. Moreover, plasmin itself can induce a potentiation of bradykinin production with consequent swelling episodes. The number of studies investigating the PA system involvement in angioedema has grown in recent years, highlighting its relevance in etiopathogenesis. In this review, we present the components and diverse functions of the PA system in physiology and its importance in angioedema pathogenesis.

High-Density Lipoprotein (HDL) in Allergy and Skin Diseases: Focus on Immunomodulating Functions

From an evolutionary perspective, lipoproteins are not only lipid transporters, but they also have important functions in many aspects of immunity. High-density lipoprotein (HDL) particles are the most abundant lipoproteins and the most heterogeneous in terms of their composition, structure, and biological functions. Despite strong evidence that HDL potently influences the activity of several immune cells, the role of HDL in allergies and skin diseases is poorly understood. Alterations in HDL-cholesterol levels have been observed in allergic asthma, allergic rhinitis, atopic dermatitis (eczema), psoriasis, urticaria, and angioedema. HDL-associated apolipoprotein (apo) A-I, apoA-IV, and apoC-III, and lyso-phosphatidylcholines potently suppress immune cell effector responses. Interestingly, recent studies provided evidence that allergies and skin diseases significantly affect HDL composition, metabolism, and function, which, in turn, could have a significant impact on disease progression, but may also affect the risk of cardiovascular disease and infections. Interestingly, not only a loss in function, but also, sometimes, a gain in function of certain HDL properties is observed. The objective of this review article is to summarize the newly identified changes in the metabolism, composition, and function of HDL in allergies and skin diseases. We aim to highlight the possible pathophysiological consequences with a focus on HDL-mediated immunomodulatory activities.

Angioedema. Interdisciplinary diagnostic and therapeutic recommendations of the Polish Dermatological Society (PTD) and Polish Society of Allergology (PTA)

Angioedema is a non-inflammatory oedema of the subcutaneous tissue and/or mucosal membranes. It most commonly coexists with urticaria wheals and is considered to be a deep form of urticaria. Less commonly, it occurs in isolation and can take two basic forms: acquired angioedema and hereditary angioedema. Currently, there are 4 defined types of acquired angioedema and 7 types of hereditary angioedema. Treatment of angioedema depends on its form and etiological factors. Especially the genetic form, i.e. hereditary angioedema, is a considerable challenge for medical specialists, particularly dermatologists and allergists.

Angioedema

Angioedema is a localized swelling of the skin and submucosal tissues and is generally benign and self-limiting. However, it can be life threatening if angioedema involves the upper airway, resulting in airway obstruction. Airway protection would be critical and lifesaving in patients with angioedema irrespective of the underlying etiology. Detailed history and physical examination can help identify the underlying mechanism of angioedema in an individual patient (ie, mast-cell versus bradykinin-mediated angioedema). Treatment of angioedema depends on the underlying etiology. Mast cell-mediated angioedema is generally responsive to steroids, antihistamines, and epinephrine (when indicated), unlike bradykinin-mediated disease. [Pediatr Ann. 2019;48(12):e473-e478.].

Angioedema: a rare and sometimes delayed side effect of angiotensin-converting enzyme inhibitors

The effects of angiotensin converting enzyme (ACE) inhibitors result from the inhibition of the ACE (kininase II) to ultimately influence both the renin-angiotensin system and the degradation of the bradykinin (BK) metabolism. ACE inhibitors block the degradation of BK and substance P by ACE. In addition, an active metabolite of BK (Des-Arg9-BK) is catalysed by kininase I and its degradation is controlled in part by the conversion enzyme. These molecules have been associated with increased plasma extravasation associated with ACE inhibitors. ACE inhibitors are the leading cause of drug-induced Angioedema (AE). Symptoms of AE mainly occur after the first month of treatment by ACE. However, very late onset cases, sometimes after several years of stable therapy, are also described in the literature. It has been observed that patients previously stable under ACE inhibitor will most likely develop AE soon after the addition of another medication, including the combination of aspirin or non-steroid anti-inflammatory drugs with ACE inhibitor which has proved to be the most common cause, accounting for close to 50% of all AE cases related to ACE inhibitors. This side effect of ACE inhibitors, sometimes very late and rare, deserves to be recalled.

Hereditary Angio-Oedema for Dermatologists

Among angio-oedema patients, hereditary angio-oedema (HAE) should not be overlooked. Besides skin swellings, these patients might have very painful abdominal attacks and potentially life-threatening angio-oedema of the upper airway. They will not respond to traditional anti-allergic therapy with antihistamines, corticosteroids, and adrenaline, and instead need specific drugs targeting the kallikrein-kinin pathway. Classically, patients with HAE have a quantitative or qualitative deficiency of the C1 inhibitor (C1INH) due to different mutations in SERPING1, although a new subtype with normal C1INH has been recognised more recently. This latter variant is diagnosed based on clinical features, family history, or molecular genetic testing for mutations in F12, ANGPT1,or PLG.The diagnosis of HAE is often delayed due to a general unfamiliarity with this orphan disease. However, undiagnosed patients are at an increased risk of unnecessary surgical interventions or life-threatening laryngeal swellings. Within the last decade, new and effective therapies have been developed and launched for acute and prophylactic therapy. Even more drugs are under evaluation in clinical trials. It is therefore of utmost importance that patients with HAE are diagnosed as soon as possible and offered relevant therapy with orphan drugs to reduce morbidity, prevent mortality, and improve quality of life.

Retrospective Review of Exceptions for Angiotensin-Converting Enzyme Inhibitor or Angiotensin II Receptor Blocker Recommendations for a Diabetic Medicare Population

BACKGROUND

Renin-angiotensin system (RAS) antagonists are recommended for people with diabetes and hypertension or with elevated urinary albumin excretion. RAS antagonists are beneficial for some, yet clinically inappropriate for others. The percentage of patients for whom RASs are clinically inappropriate has not been compared across health plans.

OBJECTIVES

To (a) identify reasons why RAS therapy was not recommended and (b) compare exception percentages between health plans.

METHODS

This retrospective, cross-sectional analysis included Medicare Part D beneficiaries with diabetes, enrolled in health plans (n = 96) participating in a university-based medication therapy management (MTM) program between January 1 and December 31, 2013. The MTM program evaluated patient eligibility for RAS therapy via (1) a clinically derived software system assessing demographics and medication history, and (2) telepharmacist-delivered medication reviews. The MTM program database calculated the number of patients with diabetes and percentage of RAS therapy exceptions.

RESULTS

An average of 55% of patients with diabetes qualified for MTM (range: 19%-88%). Of the 218,589 eligible, 94,359 had 1 or more reasons contraindicating RAS therapy (exception). For an average of 29% of patients, it was inappropriate to recommend the addition of an RAS antagonist; the overall exception rate ranged from 3% to 83%, suggesting a wide variation of exception rates for all health plans.

CONCLUSIONS

A substantial difference existed across health plans where RAS therapy was considered clinically inappropriate to recommend for patients with diabetes. Future research must examine variations in therapy exceptions to understand the effect of encouraging broad-population RAS antagonist use.

DISCLOSURES

SinfoníaRx provided funding for this project. Wild, Boesen, and Werner are employed by SinfoniaRx, which provided grant funding to the University of Arizona College of Pharmacy for the conduct of this study. This project was presented at the AMCP 27th Annual Meeting and Expo; April 8-10, 2015; San Diego, CA.

Threatened Respiratory Compromise in the Setting of Isolated Angioedema

Isolated angioedema of the uvula, or Quincke’s disease, is a rare condition that can cause respiratory compromise. Although typically self-limiting, episodes of angioedema may require prompt therapy to prevent obstruction of the proximal airway. In this case report we review the appropriate steps for initial evaluation of patients with suspected angioedema, primary etiologies, and appropriate initial therapy.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

Clinical experiences and case review of angiotensin II receptor blocker-related angioedema in Korea

Although angiotensin-converting enzyme inhibitor-related angioedema is well known, angiotensin II receptor blocker (ARB)-related angioedema has not been extensively studied because of its lower incidence. Therefore, ARB-related angioedema is likely to be overlooked in the clinical setting. We analysed the medical records of adults who had been prescribed ARB and diagnosed with angioedema between 2009 and 2015. All adults over the age of 18 years who were initially administered ARB between 1 January 2009 and 31 December 2015 were selected as participants in this study. To confirm whether the angioedema was actually due to the administration of ARB, we conducted a chart review. A total of 35 584 patients were prescribed ARB for the first time when visiting the Seoul St. Mary's Hospital during the study period. Twenty-four patients diagnosed with angioedema for other reasons prior to their first prescription of ARB were excluded from this study. ARB-related angioedema was suspected in six of 35 560 patients (0.02%) who were initially prescribed ARB during the study period. The manifestation of ARB-related angioedema ranged from several days (1/6 case) to several years (3/6 cases). Some patients continued taking ARB with intermittent antihistamine or steroid therapy. In such cases, angioedema symptoms improved but did not completely resolve. Its diagnosis can be delayed and the symptoms may be recurrent as symptoms improve with antihistamine use. In some cases, the same person had different reactions depending on the type of ARB. Definitively diagnosing ARB-related angioedema is difficult, and physicians often overlook angioedema without suspecting that it is an adverse effect of ARB. Close attention of physicians and improved patient education can reduce the incidence of ARB-related angioedema.

Angioedema Associated With Nebulized Recombinant Human DNase in a Preterm Infant: Case Report

Pulmonary atelectasis leads to difficulties in weaning of the neonates from mechanical ventilation. The management of persistent atelectasis in neonates constitutes a common challenge for physicians. Several reports suggested Recombinant human DNase (rhDNase) as a beneficial therapy for neonates with persistent atelectasis by reducing mucous viscosity. No adverse effect associated with rhDNase treatment was reported in neonates. Herein, we report probable adverse reactions associated with rhDNase use in a preterm infant. Therefore, we suggest that clinicians must be aware of this reaction in neonates and should carefully follow up these infants for the development of adverse reactions. We think that more clinical experience and data are needed to define its tolerability and adverse effect profile in neonates.

[Acquired C1 esterase inhibitor deficiency via bradykinin-mediated angioedema: Four cases]

BACKGROUND

Acquired C1-esterase inhibitor (C1-INH) deficiency angioedema (C1-INH-AAE) is a form of bradykinin-mediated angioedema. This rare disorder is due to acquired consumption of C1-INH, hyperactivation of the classic pathway of human complement, and potentially fatal recurrent angioedema symptoms. Clinical symptoms of C1-INH-AAE are very similar to those of hereditary angioedema (HAE) but usually appear after the fourth decade of life and induce abdominal pain less frequently. Laboratory tests are essential in establishing the diagnosis with low levels or abnormal structure and function of C1-INH. Most patients present C1-INH autoantibodies. Furthermore, C1q is reduced in AAE, contrary to HAE. The long-term prognosis is determined by associated hematologic malignancies.

PATIENTS AND METHODS

We report 4 cases of C1-INH-AAE associated with lymphoproliferative disorders referred to the Reference Centre for Angioedema of Besançon, France. The patients were aged between 60 and 77 years. C1 INH antibodies were found in three patients. Symptoms were triggered by angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) in 3 patients. Hematologic malignancy was present at diagnosis (one case of chronic lymphoid leukemia) or was diagnosed during follow-up (one case of indolent marginal zone non-Hodgkin lymphoma and two cases of monoclonal gammopathy).

DISCUSSION

C1-INH-AAE induced by ACE inhibitors or ARBs may be associated with hematologic malignancies. This form of revelation does not necessarily indicate a diagnosis of ACE or ARBs angioedema, and screening should therefore be performed for C1 Inh and C1q. An underlying hematologic malignancy should be routinely sought and the long-term prognosis determined.

A missense mutation in the plasminogen gene, within the plasminogen kringle 3 domain, in hereditary angioedema with normal C1 inhibitor

Hereditary angioedema (HAE) is a genetically heterogeneous disease that is characterized by recurrent skin swelling, abdominal pain attacks, and potentially life-threatening upper airway obstruction. The two classic types, HAE types I and II, are both caused by mutations in the complement C1 inhibitor (SERPING1) gene resulting either in a quantitative or a qualitative deficiency of C1 inhibitor. In so-called HAE type III, in contrast, patients show normal C1 inhibitor measurements in plasma ('HAE with normal C1 inhibitor'). As previously shown by us, one subgroup of 'HAE with normal C1 inhibitor' is caused by mutations of the coagulation factor XII (F12) gene. For the present study, following the exclusion of numerous candidate genes, we screened eight unrelated index patients representing eight 'HAE families with normal C1 inhibitor and no F12 mutation' for mutations in the plasminogen (PLG) gene. A rare non-conservative missense mutation was newly identified in exon 9 of the PLG gene. This mutation (c.1100A > G), encountered in three out of eight patients, predicts a lysine-to-glutamic acid substitution in position 311 of the mature protein (p.Lys311Glu). Using isoelectric focusing of plasma samples followed by an immunoblotting procedure we demonstrated that the presence of the mutation is associated with a dysplasminogenemia, namely the presence of an aberrant plasminogen protein. The predicted structural and functional impact of the mutation, its absence in 139 control individuals, and its co-segregation with the phenotype in three large families provide strong support that it causes disease. Extending a previously proposed gene-based alphabetic nomenclature for the various HAE types one may use the term 'HAE type C' for the HAE entity described here.