Effectiveness of ecallantide in treating angiotensin-converting enzyme inhibitor-induced angioedema in the emergency department

Corticosteroids in critically ill patients: A narrative review

Corticosteroids have been utilized in modern medicine for decades. Many indications have been investigated across various treatment settings with both benefit and harm observed. Given the instability of critically ill patients, the increased risk of corticosteroid-related complications, and the pervasive comorbidities, patients who receive corticosteroids must be carefully managed. Common critical care disease states in which corticosteroids have been studied and are routinely utilized include acute respiratory distress syndrome, adrenal insufficiency, angioedema, asthma, chronic obstructive pulmonary disease, community-acquired pneumonia, coronavirus disease 2019, septic shock, and spinal cord injury. Benefits of corticosteroids include an improvement in disease state-specific outcomes, decreased hospital length of stay, decreased mechanical ventilatory support, and decreased mortality. The harm of corticosteroids is well documented through adverse effects that include, but are not limited to, hyperglycemia, tachycardia, hypertension, agitation, delirium, anxiety, immunosuppression, gastrointestinal bleeding, fluid retention, and muscle weakness. Furthermore, corticosteroids are associated with increased health care costs through adverse effects as well as drug acquisition and administration costs. Given the assortment of agents, dosing, benefits, risks, and utilization in the critical care setting, there may be difficulty with identifying the appropriate places for use of corticosteroids in therapy. There currently exists no comprehensive report detailing the use of corticosteroids in the aforementioned disease states within the critical care setting. This narrative review sets out to describe these in detail.

Tranexamic acid for angiotensin-converting enzyme inhibitor-induced angioedema

Approximately 0.7% of patients taking angiotensin-converting enzyme inhibitors (ACEIs) develop ACEI-induced angioedema (ACEI-IA). With no approved treatments for ACEI-IA, the risk of complications is concerning. Tranexamic acid (TXA) has the potential to prevent intubations and resolve ACEI-IA by inhibiting the downstream production of bradykinin. In this review, we aim to evaluate the safety and efficacy of TXA use in ACEI-IA. We queried the PubMed database for studies involving TXA for ACEI-IA from January 2003 to January 2023. Seven studies met the study inclusion criteria. Our results demonstrate that TXA may improve angioedema symptoms and prevent intubation. In addition, its availability, low cost, and safety profile support its use for improving the symptoms and complications of ACEI-IA in an emergency setting.

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

Bradykinin Metabolism and Drug-Induced Angioedema

Bradykinin (BK) metabolism and its receptors play a central role in drug-induced angioedema (AE) without urticaria through increased vascular permeability. Many cardiovascular and diabetic drugs may cause BK-mediated AE. Angiotensin-converting enzyme inhibitors (ACEIs) and neprilysin inhibitors impair BK catabolism. Dipeptidyl peptidase-IV (DPP-IV) inhibitors reduce the breakdown of BK and substance P (SP). Moreover, angiotensin receptor blockers, thrombolytic agents, and statins may also induce BK-mediated AE. Understanding pathophysiological mechanisms is crucial for preventing and treating drug-induced AE.

Angioedema in the Absence of C1 Esterase Inhibitor Deficiency in a Young Patient With Anti-dsDNA Negative Lupus Nephritis

Hereditary angioedema (HAE) is an autosomal dominant condition marked by a lack of functioning C1 esterase inhibitor (C1-INH). In contrast, acquired angioedema (AAE) due to a deficiency of C1 esterase inhibitor (AAE-C1-INH) may be the manifestation of an underlying lymphoproliferative, neoplastic, or autoimmune condition. Both are potentially fatal. The C1q protein is normal in HAE but low in AAE. A third mechanism has been reported to cause angioedema, especially in systemic lupus erythematosus (SLE) patients. AAE, which happens in association with SLE, may respond well to steroids. Here we present a case of AAE in a young female with SLE that led to upper airway compromise, requiring endotracheal intubation. Early detection and treatment of such cases can lead to an outstanding prognosis by preventing airway compromise and anoxic brain injury. Even though it is a condition of either very young or middle-aged patients, practitioners must be aware of this uncommon disease linked with SLE in adolescents and young adults.

A Case of Refractory Angioedema

Angioedema is an acute disorder that affects mucous membranes and the deepest layers of the skin along with underlying tissue, marked by rapid swelling, large welts, and pain. There are 3 major subtypes of angioedema: mast-cell mediated, bradykinin-mediated, and multifactorial or unclear mechanism subtype. The most common subtype of bradykinin-mediated angioedema is ACE-inhibitor induced, which disproportionately affects African-Americans. It is most often self-limiting and usually responds to the withdrawal of the offending agent. The prolonged duration of angioedema is uncommon in the absence of a persistent stimulus, though it is more likely when there is an abnormality of the metabolic pathways, such as in hereditary angioedema or other gene polymorphisms affecting the complement system. We present a case of severe angioedema that persisted for over a month and required a tracheostomy to manage the airway.

Large Predominance of Off-Label Prescriptions of C1-Inhibitor Concentrates and Icatibant in a Real-Life Setting: A Retrospective Clinical Study

C1-inhibitor (C1INH) concentrates and the selective bradykinin B2 receptor antagonist icatibant are approved only for treating hereditary angioedema with C1INH deficiency. Yet, they are regularly prescribed off label in other types of bradykinin-mediated angioedema including angiotensin-converting enzyme inhibitor (ACEi)-related and undetermined angioedema. We conducted a retrospective chart review of inpatient prescriptions of C1INH concentrates and icatibant between 2016 and 2020 in the University Hospital of Angers. The first outcome was the proportion of prescriptions with explicit indication. Then, we determined the compliance of prescriptions with European Medicines Agency approvals and the French bradykinin-mediated angioedema reference center guidelines. Finally, we estimated the economic impact of inappropriate prescribing. The therapeutic indication was explicit in 90.4% of prescriptions (n = 66/73). Only 17.8% of prescriptions were for hereditary angioedema with C1INH deficiency, while 31.5% were for ACEi-related and 28.7% for undetermined angioedema. However, most off-label prescriptions were consistent with the French bradykinin-mediated angioedema reference center guidelines (73.3%). We estimated that 13% of drug expenditures were potentially excessive. The predominance of off-label prescriptions may be explained by the infrequency of hereditary angioedema and the absence of approved alternatives in other types of bradykinin-mediated angioedema. Most attacks were related to ACEis. Epinephrine was rarely prescribed as first-line therapy in attacks of unknown origin. Given the high prices of these drugs, we advocate the development of a readily available management algorithm of angioedema to reduce inappropriate prescriptions in our center. In addition, we think that the drug prescription circuit should be redesigned to ensure the traceability of prescribed vials in the dispensing areas.

Bradykinin-induced angioedema in the emergency department

Background

Acute airway angioedema commonly occurs through two distinct mechanisms: histamine- and bradykinin-dependent. Although they respond to distinct treatments, these two potentially life-threatening states present similarly. Poor recognition of the bradykinin-dependent pathway leads to treatment errors in the emergency department (ED), despite the availability of multiple pharmacologic options for hereditary angioedema (HAE) and other forms of bradykinin-induced angioedema. Here, we consider the pathophysiology and clinical features of bradykinin-induced angioedema, and we present a systematic literature review exploring the effectiveness of the available therapies for managing such cases.

Methods

PubMed searches using ‘emergency’, ‘bradykinin’ and various therapeutic product names identified studies reporting the efficacy of treatments for bradykinin-induced angioedema in the ED setting. In all, 22 studies met prespecified criteria and are analysed here.

Findings

Whereas histamine-induced angioedema has a faster onset and often presents with urticaria, bradykinin-induced angioedema is slower in onset, with greater incidence of abdominal symptoms. Acute airway angioedema in the ED should initially be treated with anaphylactic protocols, focusing on airway management and treatment with epinephrine, antihistamine and systemic steroids. Bradykinin-induced angioedema should be considered if this standard treatment is not effective, despite proper dosing and regard of beta-adrenergic blockade. Therapeutics currently approved for HAE appear as promising options for this and other forms of bradykinin-induced angioedema encountered in the ED.

Conclusion

Diagnostic algorithms of bradykinin-induced angioedema should be followed in the ED, with early use of approved therapies to improve patient outcomes.

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

Tranexamic Acid for the Emergency Treatment of Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

INTRODUCTION

Angioedema is a rare but potentially life-threatening adverse effect associated with the use of angiotensin-converting enzyme (ACE) inhibitors. Various therapies, including ecallantide, icatibant, complement-1 esterase inhibitors, and fresh frozen plasma, have been used for treatment with inconsistent results and significant adverse effects. Tranexamic acid (TXA) is used as an alternative for the treatment of hereditary angioedema and it may be an attractive option for the treatment of ACE inhibitor-induced angioedema (ACEi-AE) in the emergency department (ED). The purpose of this study was to evaluate the impact of TXA administration on rates of intubation in patients presenting to the ED with suspected ACEi-AE.

METHODS

This was an institutional review board-approved, retrospective cohort study conducted at a single-site ED. All patients who received TXA for ACEi-AE in the ED between January 1, 2019 and March 31, 2021 were eligible for inclusion. The primary outcome was the proportion of patients who required intubation for suspected ACEi-AE.

RESULTS

A total of 16 patients received TXA in the ED for suspected ACEi-AE during the study timeframe. Of these, two patients were intubated prior to administration of TXA. The remaining 14 patients did not require intubation following TXA administration.

CONCLUSION

Administration of TXA was associated with a low rate of adverse effects and did not contribute to further morbidity when added to standard care in patients presenting to the ED with suspected ACEi-AE.

What's New in the Treatment of Urticaria and Angioedema

Chronic urticaria and angioedema are diseases often managed by Allergy and Immunology specialists. Recent international guidelines have outlined a stepwise approach to management of patients using dose escalation of second-generation antihistamines followed by use of omalizumab and finally cyclosporine in more refractory cases. In select patients (those with refractory chronic urticaria), nonbiologic alternative medications with anti-inflammatory or immunosuppressant activity may be considered. Angioedema without wheals may have several different pathophysiologic mechanisms. Optimal management of mast cell-mediated angioedema is less clear but is often managed similar to chronic spontaneous urticaria. Drug-induced angioedema due to angiotensin-converting enzyme inhibitors is a common cause of angioedema in the emergency department. Although bradykinin is thought to be a primary mediator for this type of angioedema, studies of targeted therapies have been generally disappointing. In contrast, several targeted therapies have been proven successful using acute and preventive approaches for management of hereditary angioedema. Further developments, including novel biologics, novel oral therapies, and gene therapy approaches, may hopefully continue to broaden therapeutic options to ensure optimal individual management of patients with hereditary angioedema.

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.

C1 esterase inhibitor use in the management of lisinopril-induced angioedema: A case series

OBJECTIVE

Review 4 patients who presented with presumed lisinopril-induced angioedema and received C1 esterase inhibitor (C1-INH).

CASE SUMMARY

Four patients received C1-INH for presumed lisinopril-induced angioedema. In all cases, angioedema was attributed to lisinopril use after the patients' symptoms did not resolve after receiving other interventions. The patients received either 1500 units or 2000 units of C1-INH. All patients' symptoms resolved after receiving a single C1-INH dose, and all were discharged home within 48 hours of receiving C1-INH.

PRACTICE IMPLICATIONS

On the basis of the available literature and our study, C1-INH may effectively treat angiotensin-converting enzyme inhibitor-induced angioedema (ACEi-AE). Owing to the low incidence of ACEi-AE and the high cost of C1-INH, physicians should consider limiting the use of C1-INH to patients who remain symptomatic after the initial interventions and are at risk of a compromised airway.

A Case of Prolonged Angioedema After Cardiac Surgery

Angioedema (AE) is a transient capillary leak syndrome, caused by either histamine or bradykinin, that presents as an acute nonpitting swelling of the skin, subcutaneous tissues, and mucous membranes of the face, lips, tongue, upper airways, and gastrointestinal tract, with or without a rash. A lack of response to antihistamines, steroids, and epinephrine suggests a bradykinin-mediated AE. Bradykinin-AE may be inherited, acquired, or drug related. Mechanism of increased bradykinin can include decreased C1-esterase inhibitor (C1-INH) levels or activity, increased bradykinin production, or decreased bradykinin breakdown, the latter occurring during angiotensin converting enzyme inhibitor (ACEi). A 65-year-old woman had coronary artery bypass grafting, which was complicated by prolonged bradykinin-AE owing to ACEi, requiring prolonged endotracheal tube intubation. Treatment with a C1-esterase inhibitor (Berinert) on postoperative day 7 resulted in a dramatic improvement in airway edema and tongue swelling within 7 hours, and the patient was subsequently extubated. The case is unusual because of the prolonged course of AE and the benefit of late administration of C1-INH concentrate.

ACE inhibitor-mediated angioedema

Angioedema (AE) occurring during ACE inhibitor therapy (ACEi-AE) is a rare complication involving between 0.1 and 0.7% of treated patients. AE can also complicate other therapeutic regimens that block the renin-angiotensin aldosterone system. Other drugs, such as immune suppressors, some type of antidiabetics or calcium antagonists, can increase the likelihood of ACEi-AE when associated to ACEi. There is a clear ethnic predisposition, since African-Americans or Hispanics show a higher prevalence of this condition compared to Caucasians. At least in African-Americans the genetic predisposition accounts for a general higher prevalence of AE, independently from the cause. People that experience ACEi-AE may have some recurrence when they are switched to an angiotensin-receptor blocker (ARB); however, epidemiological studies on large cohorts have shown that angiotensin receptor blockers (ARB) do not increase the likelihood of AE compared to other antihypertensives. Clinical manifestations consist of edema of face, lips, tongue, uvula and upper airways, requiring intubation or tracheotomy in severe cases. Attacks last for 48-72 h and require hospital admission in most cases. Intestinal involvement with sub-occlusive symptoms has also been reported. The pathogenesis of ACEi-AE depends mainly on a reduced catabolism and accumulation of bradykinin, which is normally metabolized by ACE. Genetic studies have shown that some single nucleotide polymorphisms at genes encoding relevant molecules for bradykinin metabolism and action may be involved in ACEi-AE, giving a basis for the ethnic predisposition. Treatment of ACEi-AE is still a matter of debate. Corticosteroids and antihistamines do not show efficacy. Some therapeutic attempts have shown some efficacy for fresh frozen plasma or C1 inhibitor concentrate infusion. Interventional studies with the specific bradykinin receptor antagonist icatibant have shown conflicting results; there might be a different ethnic predisposition to icatibant efficacy which has been proven in caucasian but not in black patients.

Evaluation and Management of Angioedema in the Emergency Department

Angioedema is defined by non-dependent, non-pitting edema that affects several different sites and is potentially life-threatening due to laryngeal edema. This narrative review provides emergency physicians with a focused overview of the evaluation and management of angioedema. Two primary forms include histamine-mediated and bradykinin-mediated angioedema. Histamine-mediated forms present similarly to anaphylaxis, while bradykinin-mediated angioedema presents with greater face and oropharyngeal involvement and higher risk of progression. Initial evaluation and management should focus on evaluation of the airway, followed by obtaining relevant historical features, including family history, medications, and prior episodes. Histamine-mediated angioedema should be treated with epinephrine intramuscularly, antihistaminergic medications, and steroids. These medications are not effective for bradykinin-mediated forms. Other medications include C1-INH protein replacement, kallikrein inhibitor, and bradykinin receptor antagonists. Evidence is controversial concerning the efficacy of these medications in an acute episode, and airway management is the most important intervention when indicated. Airway intervention may require fiberoptic or video laryngoscopy, with preparation for cricothyrotomy. Disposition is dependent on patient's airway and respiratory status, as well as the sites involved.

Angioedema and emergency medicine: From pathophysiology to diagnosis and treatment

Angioedema is a self-limiting edema of the subcutaneous or submucosal tissues due to localised increase of microvascular permeability whose mediator may be histamine or bradykinin. Patients present to emergency department when angioedema involves oral cavity and larynx (life-threatening conditions) or gut (mimicking an acute abdomen). After initial evaluation of consciousness and vital signs to manage breathing and to support circulation if necessary, a simple approach can be applied for a correct diagnosis and treatment. Forms of edema such as anasarca, myxedema, superior vena cava syndrome and acute dermatitis should be ruled out. Then, effort should be done to differentiate histaminergic from non-histaminergic angioedema. Concomitant urticaria and pruritus suggest a histaminergic origin. Exposure to allergens and drugs (mainly ACE inhibitors and non steroidal anti-inflammatory drugs) should be investigated as well as a family history of similar symptoms. Allergic histaminergic angioedema has a rapid course (minutes) whereas non histaminergic angioedema is slower (hours). Since frequently the intervention needs to be immediate, the initial diagnosis is only clinical. However, laboratory tests can be subsequently confirmatory. Allergic angioedema is sensitive to standard therapies such as epinephrine, glucocorticoids and antihistamines whereas non histaminergic angioedema is often resistant to these drugs. Therapeutic options for angioedema due C1-inhibitor deficiencies are C1-inhibitor concentrates, icatibant and ecallantide. If these drugs are not available, fresh frozen plasma can be considered. All these medications have been used also in ACE inhibitor-induced angioedema with variable results thus they are not currently recommended whereas experts agree on the discontinuation of the causative drug.

Efficacy of Treatment of Non-hereditary Angioedema

Non-hereditary angioedema (AE) with normal C1 esterase inhibitor (C1INH) can be presumably bradykinin- or mast cell-mediated, or of unknown cause. In this systematic review, we searched PubMed, EMBASE, and Scopus to provide an overview of the efficacy of different treatment options for the abovementioned subtypes of refractory non-hereditary AE with or without wheals and with normal C1INH. After study selection and risk of bias assessment, 61 articles were included for data extraction and analysis. Therapies were described for angiotensin-converting enzyme inhibitor-induced AE (ACEi-AE), for idiopathic AE, and for AE with wheals. Described treatments consisted of ecallantide, icatibant, C1INH, fresh frozen plasma (FFP), tranexamic acid (TA), and omalizumab. Additionally, individual studies for anti-vitamin K, progestin, and methotrexate were found. Safety information was available in 26 articles. Most therapies were used off-label and in few patients. There is a need for additional studies with a high level of evidence. In conclusion, in acute attacks of ACEi-AE and idiopathic AE, treatment with icatibant, C1INH, TA, and FFP often leads to symptom relief within 2 h, with limited side effects. For prophylactic treatment of idiopathic AE and AE with wheals, omalizumab, TA, and C1INH were effective and safe in the majority of patients.

Angiotensin-converting Enzyme Inhibitor and Other Drug-associated Angioedema

Nonsteroidal antiinflammatory agents, β-lactam antibiotics, non-β lactam antibiotics, and angiotensin-converting enzyme inhibitors are the most common classes of drugs that cause angioedema. Drug-induced angioedema is known to occur via mechanisms mediated by histamine, bradykinin, or leukotriene, and an understanding of these mechanisms is crucial in guiding therapeutic decisions. Nonallergic angioedema occurs in patients with genetic variants that affect metabolism or synthesis of bradykinin, substance P, prostaglandins, or leukotrienes, or when patients are taking drugs that have synergistic mechanisms. The mainstay in treatment of nonallergic drug-induced angioedema is cessation of the offending agents.

Pharmacotherapy for Angiotensin-Converting Enzyme Inhibitor–Induced Angioedema: A Systematic Review

Objective

Angioedema is a potentially life-threatening complication of angiotensin-converting enzyme inhibitor (ACEI) use, occurring in up to 0.5% of users. Although the pathophysiology of ACEI-induced angioedema is attributable to elevated serum bradykinin, standard management typically includes corticosteroids and antihistamines. We sought to summarize the evidence supporting pharmacotherapy for ACEI-induced angioedema.

Data Sources

PubMed, MEDLINE, and Embase portals.

Methods

A systematic literature review was conducted according to the PRISMA guidelines. Databases were queried by 3 independent reviewers for English-language studies published between 1980 and 2017. The initial search screened for all occurrences of “angioedema” and then was further refined to include studies of ACEI-related cases and exclude hereditary angioedema.

Results

Five articles representing 218 cases were identified, including 3 randomized controlled trials and 2 prospective case series with historical controls. One of 2 studies of icatibant (bradykinin B2 receptor antagonist) found more rapid symptom improvement than that with a control group of corticosteroids and antihistamines. Two studies of ecallantide (plasma kallikrein inhibitor) and 1 study of C1 inhibitor replacement found no significant benefit over control. No studies were identified that compared the efficacy of corticosteroids with antihistamines, of one dose with another, of fresh frozen plasma, or of combination therapy.

Conclusion

The efficacy of treatment of ACEI-induced angioedema with bradykinin antagonists, kallikrein inhibitor, and C1 inhibitor warrants further study. Although consistent benefit of these medications has not been demonstrated, their use has not caused harm. One study examining off-label use of icatibant has demonstrated efficacy over control. In addition, further study is needed to establish the efficacy and mechanism of action of standard pharmacotherapy such as corticosteroids and antihistamines in treatment of this condition.

Development and validation of the angiotensin-converting enzyme inhibitor (ACEI) induced angioedema investigator rating scale and proposed discharge criteria

BACKGROUND

The use of angiotensin-converting enzyme inhibitors (ACEI) has been associated with the development of bradykinin-mediated angioedema. With ever-widening indications for ACEI in diseases including hypertension, congestive heart failure and diabetic nephropathy, a concomitant increase in ACEI-Angioedema (ACEI-A) has been reported. At present there is no validated severity scoring or discharge criteria for ACEI-A. We sought to develop and validate an investigator rating scale with corresponding discharge criteria using clinicians experienced in treating ACEI-A.

METHODS

In-depth, 60-min qualitative telephone interviews were conducted with 12 US-based emergency physicians. Beforehand, clinicians were sent four case studies describing patients experiencing different severities of angioedema attacks. Clinicians were initially asked open-ended questions about their experience of patients' symptoms, treatment and discharge decisions. Clinicians then rated each patient case study and discussed patient diagnoses, ratings of symptom severity and discharge evaluation. The ratings were used to assess inter-rater reliability of the scale using the intra-class correlation coefficient (ICC) using IBM SPSS analysis Version 19 software.

RESULTS

The findings provide support focusing on four key symptoms of airway compromise scored on a 0-4 scale: 1) Difficulty Breathing, 2) Difficulty Swallowing, 3) Voice Changes and 4) Tongue Swelling and the corresponding discharge criteria of a score of 0 or 'No symptoms' for Difficulty Breathing and Difficulty Swallowing and a score of 0 or 1 indicating mild or absence of symptoms for Voice Change and Tongue Swelling. Eleven clinicians agreed the absence of standardized discharge criteria supported the use of this scale. All physicians concurred with the recommended discharge criteria. The clinician ratings provided evidence of strong inter-rater reliability for the rating scale (ICC > 0.80).

CONCLUSION

The investigator rating scale and discharge criteria are clinically valid, relevant and reliable. Moreover, both address the current unmet need for standardized ED discharge criteria.

Angioedema in the emergency department: a practical guide to differential diagnosis and management

Background

Angioedema is a common presentation in the emergency department (ED). Airway angioedema can be fatal; therefore, prompt diagnosis and correct treatment are vital.

Objective of the review

Based on the findings of two expert panels attended by international experts in angioedema and emergency medicine, this review aims to provide practical guidance on the diagnosis, differentiation, and management of histamine- and bradykinin-mediated angioedema in the ED.

Review

The most common pathophysiology underlying angioedema is mediated by histamine; however, ED staff must be alert for the less common bradykinin-mediated forms of angioedema. Crucially, bradykinin-mediated angioedema does not respond to the same treatment as histamine-mediated angioedema. Bradykinin-mediated angioedema can result from many causes, including hereditary defects in C1 esterase inhibitor (C1-INH), side effects of angiotensin-converting enzyme inhibitors (ACEis), or acquired deficiency in C1-INH. The increased use of ACEis in recent decades has resulted in more frequent encounters with ACEi-induced angioedema in the ED; however, surveys have shown that many ED staff may not know how to recognize or manage bradykinin-mediated angioedema, and hospitals may not have specific medications or protocols in place.

Conclusion

ED physicians must be aware of the different pathophysiologic pathways that lead to angioedema in order to efficiently and effectively manage these potentially fatal conditions.

Effect of bradykinin receptor antagonism on ACE inhibitor-associated angioedema

BACKGROUND

The B₂ receptor antagonist icatibant is approved for treatment of attacks of hereditary angioedema. Icatibant has been reported to decrease time-to-resolution of angiotensin-converting enzyme (ACE) inhibitor-associated angioedema in 1 study of European patients.

OBJECTIVE

We sought to test the hypothesis that a bradykinin B₂ receptor antagonist would shorten time-to-resolution from ACE inhibitor-associated angioedema.

METHODS

Patients with ACE inhibitor-associated angioedema (defined as swelling of lips, tongue, pharynx, or face during ACE inhibitor use and no swelling in the absence of ACE inhibitor use) were enrolled at Vanderbilt University Medical Center from October 2007 through September 2015 and at Massachusetts General Hospital in 2012. C1 inhibitor deficiency and patients with bowel edema only were excluded. Patients were randomized within 6 hours of presentation to subcutaneous icatibant 30 mg or placebo at 0 and 6 hours later. Patients assessed severity of swelling using a visual analog scale serially following study drug administration or until discharge.

RESULTS

Thirty-three patients were randomized and 31 received treatment, with 13 receiving icatibant and 18 receiving placebo. One patient randomized to icatibant did not complete the visual analog scale and was excluded from analyses. Two-thirds of patients were black and two-thirds were women. Time-to-resolution of symptoms was similar in placebo and icatibant treatment groups (P = .19 for the primary symptom and P > .16 for individual symptoms of face, lip, tongue, or eyelid swelling). Frequency of administration of H1 and H2 blockers, corticosteroids, and epinephrine was similar in the 2 treatment groups. Time-to-resolution of symptoms was similar in black and white patients.

CONCLUSIONS

This study does not support clinical efficacy of a bradykinin B₂ receptor antagonist in ACE inhibitor-associated angioedema.

Angiotensin-converting enzyme inhibitor-associated angioedema treated with c1-esterase inhibitor: A case report and review of the literature

Case Report:

A 59-year old man currently on >5 years of angiotensin-converting enzyme inhibitor (ACEI) therapy presented to the emergency department with angioedema of the tongue and difficulty swallowing. After receiving conventional therapy of antihistamine, steroids, and epinephrine, the patient's condition continued to deteriorate, with imminent intubation. The patient was treated with a C1-esterase inhibitor (C1-INH) and experienced rapid resolution of symptoms, which avoided airway complications.

Discussion:

Although no therapy has been approved for the treatment of ACEI–associated angioedema (AAE), the conventional therapy (antihistamine, steroids, and epinephrine) often proves ineffective in this bradykinin-mediated angioedema. There are drugs approved and used for hereditary angioedema that may be effective in the acute phase of ACEI-AAE that may prevent the need for further interventions, such as intubation and tracheotomy. These drugs include icatibant, ecallantide, fresh frozen plasma, and C1-INH.

Conclusion:

The literature and clinical evidence indicate C1-INH can be effectively used in the treatment of ACEI-AAE to halt the progression of the condition, prevent airway compromise and the need for intervention, and lead to rapid resolution of symptoms.

Pharmacologic management of angioedema induced by angiotensin-converting enzyme inhibitors

Purpose

The published evidence on pharmacologic approaches to the management of angiotensin-converting enzyme inhibitor (ACEI)–induced angioedema is reviewed.

Summary

Angioedema is a serious, potentially life-threatening adverse effect of ACEI use. Although the underlying mechanism is not fully understood, excess bradykinin produced through a complex interplay between the kallikrein-kinin and renin-angiotensin-aldosterone systems is thought to play a major role. The nonallergic nature of the reaction renders traditional therapies (corticosteroids and antihistamines) ineffective because those agents do not modify the proposed pathophysiology. Fresh frozen plasma (FFP) provides kinase II, a protein that breaks down bradykinin. Case reports support FFP as a treatment for ACEI-induced angioedema, but no formal evaluations have been completed to date. Both ecallantide and complement 1 esterase (C1) inhibitor concentrate reduce bradykinin production through upstream inhibition of kallikrein. C1 inhibitor concentrate has been used successfully to manage ACEI-induced angioedema in a few reported cases, but robust supportive studies are lacking. Conversely, ecallantide has been evaluated in multiple randomized trials but has not been shown to offer advantages over traditional therapies. The use of icatibant, a direct antagonist of bradykinin B2 receptors, was reported to be beneficial in several case reports and in a small Phase II study, safely and rapidly reducing symptoms of ACEI-induced angioedema. An ongoing Phase III trial (NCT01919801) will better define the role of icatibant in the management of ACEI-induced angioedema.

Conclusion

FFP, C1 inhibitor, and icatibant appear to be safe and effective therapeutic options for the management of ACEI-induced angioedema, whereas it appears ecallantide should be avoided.

Off-Label Use of Agents for Management of Serious or Life-threatening Angiotensin Converting Enzyme Inhibitor–Induced Angioedema

Objective: To evaluate the place in therapy of fresh frozen plasma (FFP), C1 esterase concentrate (C1-INH), ecallantide, and icatibant in the management of angiotensin-converting enzyme inhibitor–induced angioedema (ACEI-IA). Data Sources: A literature search was performed using PubMed (1946 through August 2015) and Embase (<1966 through August 2015). References from identified articles were reviewed. Study Selection and Data Extraction: Consensus papers, practice guidelines, case reports/series, clinical trials, and meeting abstracts published in English and involving humans were included. Data Synthesis: No medications are currently Food and Drug Administration–approved for managing ACEI-IA. Emerging evidence suggests that FFP and medications approved for management of acute attacks of hereditary angioedema, another bradykinin-mediated event, may be effective for use in ACEI-IA. Positive efficacy results were reported with FFP and C1-INH while mixed results have been seen with ecallantide. Off-label icatibant has the most evidence supporting its use in ACEI-IA with rapid symptom resolution (10 minutes to 6 hours) and avoidance of intubation and tracheotomy in several cases. These agents were well-tolerated in ACEI-IA. Conclusion: ACEI-IA is typically a self-limiting event. First-line therapies include ACEI discontinuation, observation, and supportive medications (eg, corticosteroids, antihistamines, and epinephrine). Symptom progression can be life-threatening and may require interventions such as tracheotomy and intubation. Off-label use of FFP and medications approved for hereditary angioedema have resulted in rapid resolution of symptoms and avoidance of intubation. Among these agents, icatibant has the most supporting evidence and has been incorporated into practice guidelines and algorithms as a second-line agent for serious life-threatening ACE-IA.