Angioedema:

Complement system activation: bridging physiology, pathophysiology, and therapy

The complement system is a set of over 50 proteins that constitutes an essential part of the innate immune system. Complement system activation involves an organized proteolytic cascade. Overactivation of complement system activation is the main pathogenic mechanism of several diseases and contributes to the manifestations of many other conditions. This review describes the normal complement system and the role for complement dysregulation in critical illnesses, notably sepsis and acute respiratory distress syndrome. Complement activation is involved in the immune system response to pathogens but, when excessive, can contribute to tissue damage, runaway inflammation, and capillary leakage syndrome. Complement overactivation may play a key role in severe forms of coronavirus disease 2019 (COVID-19). Two diseases whose manifestations are mainly caused by complement overactivation, namely, atypical hemolytic and uremic syndrome (aHUS) and myasthenia gravis, are discussed. A diagnostic algorithm for aHUS is provided. Early complement-inhibiting therapy has been proven effective. When renal transplantation is required, complement-inhibiting drugs can be used prophylactically to prevent aHUS recurrence. Similarly, acetylcholine-receptor autoantibody-positive generalized myasthenia gravis involves complement system overactivation and responds to complement inhibition. The two main complement inhibitors used in to date routine are eculizumab and ravulizumab. The main adverse event is Neisseria infection, which is rare and preventable, but can be fatal. The complement system is crucial to health but, when overactivated, can cause or contribute to disease. Effective complement inhibitors are now available, although additional data are required to determine optimal regimens. Further research is also needed to better understand the complement system, develop advanced diagnostic tools, and identify markers that allow the personalization of treatment strategies.

Hereditary angioedema with normal C1 esterase inhibitor: Current paradigms and clinical dilemmas

Background: A diagnosis of hereditary angioedema (HAE) with normal C1 esterase inhibitor (HAE-nl-C1-INH) can be challenging and pharmacologic management is not well defined. Objective: The objective was to discuss practical considerations in the clinical management of HAE-nl-C1-INH by using illustrative clinical vignettes to highlight and/or address select challenges. Methods: This was a narrative review. Results: Symptoms of HAE-nl-C1-INH overlap with HAE types I and II; the heterogeneity of presentation and symptom burden are diagnostic challenges. A patient history, with particular attention to whether urticaria or other symptoms of mast cell mediator release are present, is important because such symptoms would strongly suggest a mast cell-mediated pathway. A family history of angioedema is informative but a lack thereof does not rule out diagnosis. Expected laboratory findings would be normal for C4, C1-INH level and function, and Complement 1q; a genetic mutational analysis may be helpful, but current assays do not include all known mutations; most cases are categorized as unknown. To align with guideline-directed treatment approaches, the following stepwise approach is suggested for suspected HAE-nl-C1-INH: (1) thoroughly investigate the possibility of response to histaminergic and/or mast cell-targeting treatments; (2) if patients with normal C4, C1-INH level and/or function fail adequate trials with histamine/mast cell-directed therapy or have a mutation that suggests bradykinin pathway involvement, follow HAE type I and II treatment guidelines. Response to medications approved for HAE types I/II provides compelling support for a high clinical suspicion of HAE-nl-C1-INH. De-labeling an HAE-nl-C1-INH diagnosis may be appropriate if the initial diagnosis was made without adequate evaluation or if new information and/or testing indicates that the patient does not actually have HAE. Conclusion: Key unmet needs in HAE-nl-C1-INH include lack of confirmatory biomarker(s) for diagnosis and lack of prospective controlled clinical studies of pharmacologic products in this patient population.

Angioedema: A Possible Complication of Amlodipine Use

Angioedema is a documented but uncommon adverse effect of dihydropyridine calcium channel blockers such as amlodipine. We present the case of a 38-year-old man who presented to the emergency department (ED) with severe swelling of his upper lip that had begun earlier in the day. His medical history was notable for hypertension treated with amlodipine; his only other medication was a multivitamin. The patient denied any known drug allergies, new foods, insect bites, recent travel, or sick contacts. Physical examination showed hypertension and massive edema isolated to the upper lip; it was otherwise unremarkable. Laboratory results showed no abnormalities aside from a slight normocytic anemia. The patient was diagnosed with angioedema, with amlodipine suspected as the cause. Amlodipine was discontinued and treatment was initiated with IV glucocorticoids and diphenhydramine. The swelling improved steadily over the next 36 hours and the patient was discharged on hospital day 3.

[Angioedema in the emergency department]

Acute angioedema is mostly found in the head and neck region. Therefore, it can be life threatening by potentially endangering air way patency. Pathophysiologically angioedemas can be divided into mast cell-mediated or bradykinin-mediated forms. Differentiation is essential due to the different therapeutic strategies. In cases of doubt, initial therapy with adrenalin, antihistamines, and glucocorticoids should be initiated. This initial emergency treatment is comparable to the treatment of allergic reactions. For diagnosed or suspected hereditary angioedema, specific treatments are available. For drug-associated forms, immediate and life-long cessation of the medication is crucial. In the emergency situation, diagnosis can only be based on medical history and clinical symptoms. Recognition of impending airway obstruction and securing the airway is of highest priority; final diagnosis must be confirmed later.

Angioedema as a Rare Presentation of Systemic Lupus Erythematosus

Angioedema (AE) is an immune-mediated tissue swelling that can be life-threatening if it compromises the airway. This makes prompt diagnosis and management of the condition excruciatingly important. It can be hereditary or associated with infections, malignancies, and autoimmune diseases. There have been reported cases in the literature where Systemic lupus erythematosus (SLE) patients developed acquired angioedema raising suspicion of a possible association between the two conditions. We describe a case of a patient with no known medical issues, presenting with acute onset of her first episode of angioedema with airway compromise. Because of the rarity of awareness of the possible association of our conditions of interest, there was an inevitable delay in diagnosis and the patient was eventually diagnosed to have SLE and associated acquired angioedema as its first presentation.  This case report highlights the importance of maintaining high suspicion for SLE in patients with an isolated first episode of AE and discusses mechanisms involved in the disease process to shed light on available treatment modalities.

Factitious Disorder: An Angioedema Copycat

Factitious disorder (FD) is a psychiatric illness in which an individual assumes the role of a patient by manifesting physical or psychological symptoms without conscious or obvious reward. Here, we present the case of a 28-year-old female with a history of endotracheal intubations 19 times secondary to anaphylaxis. During the current hospital visit, she complained of cough, shortness of breath (SOB), arthralgia, wheezing, and rashes over the chest. Serum C1 esterase inhibitor and C4 levels have been negative on multiple occasions. A previous laryngoscopy showed a normal larynx, normal vocal cords, and no obstruction. Due to the patient’s history of multiple invasive procedures, malingering was considered a possible differential diagnosis. The patient also has a past psychiatric history of major depressive disorder (MDD), post-traumatic stress disorder (PTSD), adjustment disorder with anxious mood, and anxiety disorder. Her complicated psychiatric history coupled with her multiple endotracheal intubations associated with normal laboratory findings raise the suspicion of factitious disorder. This case is meant to demonstrate the complicated matter of helping a patient whose psychiatric illnesses have put her at risk of serious health complications for the sake of assuming a sick role.

Angiotensin-converting enzyme inhibitor induced angioedema: not always a class effect? A case report and short narrative review

INTRODUCTION

Bradykinin-mediated angioedema is a rare but potentially fatal adverse event. Angioedema induced by angiotensin-converting enzyme (ACE) inhibitors is generally attributed to an inhibition of bradykinin degradation following ACE inhibition. Clinical studies on ACE inhibitors mainly focus on their efficacy. Few examine their potential to generate undesirable adverse effects, particularly with regard to angioedema.

CASE DESCRIPTION

We report here a case of angioedema occurring after ramipril initiation in a patient chronically treated with quinapril. Angioedema subsided spontaneously after ramipril discontinuation and quinapril reintroduction.

DISCUSSION AND CONCLUSIONS

Our clinical case suggests that despite similar pharmacodynamic properties, quinapril and ramipril do not have the same potential to generate angioedema. To explain this difference, we suggest a potentiation of the effect of bradykinin at the B2 receptor level by ramipril, which does not occur with quinapril. Consequently, angioedema may not always be a class effect of ACE inhibitors.

A Unique Set of Symptoms in the Background of SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) is a respiratory disease that has been reported to have a wide array of extrapulmonary manifestations. Our knowledge regarding this virus is constantly evolving, and new literature is being published every day. Children usually have a mild severity of COVID-19 infection. A variety of skin lesions have been documented in this disease. Similarly, our 18-month-old patient who was diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection had mild symptoms, but three days later he presented to the hospital with the development of urticarial lesions followed by angioedema. In this case report, we have attempted to highlight a possible association of angioedema and urticarial with coronavirus infection. Physicians should be aware of this association and should always inquire about symptoms of respiratory illness (SARS-CoV-2) while dealing with patients in whom a specific trigger for angioedema/urticaria is un-identifiable.

Critical Care Management of the Patient With Anaphylaxis: A Concise Definitive Review

OBJECTIVES

Anaphylaxis is a rapidly progressive life-threatening syndrome manifesting as pruritus, urticaria, angioedema, bronchospasm and shock. The goal of this synthetic review is to provide a practical, updated approach to the evaluation and management of this disorder and associated complications.

DATA SOURCES

A MEDLINE search was conducted with the MeSH of anaphylaxis, anaphylactic reaction, anaphylactic shock, refractory anaphylaxis and subheadings of diagnosis, classification, epidemiology, complications and pharmacology. The level of evidence supporting an intervention was evaluated based on the availability of randomized studies, expert opinion, case studies, reviews, practice parameters and other databases (including Cochrane).

STUDY SELECTION

Selected publications describing anaphylaxis, clinical trials, diagnosis, mechanisms, risk factors and management were retrieved (reviews, guidelines, clinical trials, case series) and their bibliographies were also reviewed to identify relevant publications.

DATA EXTRACTION

Data from the relevant publications were reviewed, summarized and the information synthesized.

DATA SYNTHESIS

This is a synthetic review and the data obtained from a literature review was utilized to describe current trends in the diagnosis and management of the patient with anaphylaxis with a special emphasis on newer evolving concepts of anaphylaxis endotypes and phenotypes, management of refractory anaphylaxis in the ICU setting and review of therapeutic options for the elderly patient, or the complicated patient with severe cardiorespiratory complications. Most of the recommendations come from practice parameters, case studies or expert opinions, with a dearth of randomized trials to support specific interventions.

CONCLUSION

Anaphylaxis is a rapidly progressive life-threatening disorder. The critical care physician needs to be familiar with the diagnosis, differential diagnosis, evaluation, and management of anaphylaxis. Skilled intervention in ICUs may be required for the patient with complicated, severe, or refractory anaphylaxis.

The Outcome of Critically Ill COVID-19 Patients Is Linked to Thromboinflammation Dominated by the Kallikrein/Kinin System

An important manifestation of severe COVID-19 is the ARDS-like lung injury that is associated with vascular endothelialitis, thrombosis, and angiogenesis. The intravascular innate immune system (IIIS), including the complement, contact, coagulation, and fibrinolysis systems, which is crucial for recognizing and eliminating microorganisms and debris in the body, is likely to be involved in the pathogenesis of COVID-19 ARDS. Biomarkers for IIIS activation were studied in the first 66 patients with COVID-19 admitted to the ICU in Uppsala University Hospital, both cross-sectionally on day 1 and in 19 patients longitudinally for up to a month, in a prospective study. IIIS analyses were compared with biochemical parameters and clinical outcome and survival. Blood cascade systems activation leading to an overreactive conjunct thromboinflammation was demonstrated, reflected in consumption of individual cascade system components, e.g., FXII, prekallikrein, and high molecular weight kininogen and in increased levels of activation products, e.g., C4d, C3a, C3d,g, sC5b-9, TAT, and D-dimer. Strong associations were found between the blood cascade systems and organ damage, illness severity scores, and survival. We show that critically ill COVID-19 patients display a conjunct activation of the IIIS that is linked to organ damage of the lung, heart, kidneys, and death. We present evidence that the complement and in particular the kallikrein/kinin system is strongly activated and that both systems are prognostic markers of the outcome of the patients suggesting their role in driving the inflammation. Already licensed kallikrein/kinin inhibitors are potential drugs for treatment of critically ill patients with COVID-19.

Advances in Hereditary Angioedema: The Prevention of Angioedema Attacks With Subcutaneous C1-Inhibitor Replacement Therapy

Supplemental Digital Content is Available in the Text.

Hereditary angioedema (HAE) is a debilitating condition caused by a functional C1-inhibitor (C1-INH) deficiency and characterized clinically by episodes of subcutaneous or submucosal swelling. C1-INH replacement is highly effective for preventing HAE attacks and can improve health-related quality of life. Once available only for intravenous use, C1-INH is now available as a subcutaneous formulation for self-administration, shown to provide sustained plasma levels of C1-INH and reducing the monthly median HAE attack rate by 95% versus placebo in the phase 3 COMPACT study. Subcutaneously administered C1-INH satisfies multiple unmet needs in the management of patients with HAE.

Life-threatening airway obstruction caused by angioedema in a morbidly obese postoperative patient: a case report

Background

We report a case of a morbidly obese patient who developed life-threatening airway obstruction due to angioedema.

Case presentation

A 50-year-old Japanese morbidly obese female was treated with enalapril for 10 years, with no history of angioedema. After 3 h of completion of breast cancer resection under general anesthesia with tracheal intubation, she developed airway obstruction and respiratory arrest. Her oral cavity was occupied with a swollen tongue. It was extremely difficult to determine the airway anatomical orientation although tracheal intubation was attempted using a videolaryngoscope. At this time, she probably started gasping respiration, which generated a faint bubble and revealed a possible airway. Her airway was established using a tracheal tube without confirming the glottis or the vocal cord.

Conclusions

Angioedema induced by angiotensin-converting enzyme (ACE) inhibitors is rare; however, once it occurs, it can be potentially life threatening, especially for patients with possible difficult airway. Considering the risk–benefit ratio, we must be careful in administering ACE inhibitor therapy in morbidly obese patients.

COVID's Razor: RAS Imbalance, the Common Denominator Across Disparate, Unexpected Aspects of COVID-19

A modern iteration of Occam's Razor posits that "the simplest explanation is usually correct." Coronavirus Disease 2019 involves widespread organ damage and uneven mortality demographics, deemed unexpected from what was originally thought to be "a straightforward respiratory virus." The simplest explanation is that both the expected and unexpected aspects of COVID-19 share a common mechanism. Silent hypoxia, atypical acute respiratory distress syndrome (ARDS), stroke, olfactory loss, myocarditis, and increased mortality rates in the elderly, in men, in African-Americans, and in patients with obesity, diabetes, and cancer-all bear the fingerprints of the renin-angiotensin system (RAS) imbalance, suggesting that RAS is the common culprit. This article examines what RAS is and how it works, then from that baseline, the article presents the evidence suggesting RAS involvement in the disparate manifestations of COVID-19. Understanding the deeper workings of RAS helps one make sense of severe COVID-19. In addition, recognizing the role of RAS imbalance suggests potential routes to mitigate COVID-19 severity.

H1R mediates local anesthetic-induced vascular permeability in angioedema

Angioedema may occur during local anesthetic (LA) injection in the perioperative period. Histaminergic angioedema is the most common form of angioedema. It has been reported that LA is a potential exogenous ligand for histamine receptor 1 (H₁R). Whether H₁R participates in LA-induced angioedema is still controversial. By using a constructed H₁R high-expressed cell model, siRNA transfection, pharmacologic means, and genetically modified animal models, here we showed that H₁R mediated LA-induced hyperpermeability. LA with uncycled N-methyl scaffold in the side chain (procaine, tetracaine and lidocaine) had a better strength of drug-H₁R affinity than that for LA with cycled N atom (bupivacaine and ropivacaine) by the molecular docking assay and equilibrium dissociation constant (K_D values) obtained from the cell membrane chromatography (CMC) relative standard method. Procaine, tetracaine, and lidocaine triggered big calcium mobilization in H₁R-HEK293 cells and human umbilical vein endothelial cells (HUVECs) but much weaker in NC-HEK293 cells or H₁R knockdown HUVECs. Besides, the results of transendothelial resistance measurement, paracellular flux assay and immunofluorescence showed that procaine induced H₁R-dependent hyperpermeability, which involved in PLCγ/IP3R/PKC, ERK1/2, Akt signaling pathways, downstream vascular endothelial cadherin (VE-cad) destabilization. Furthermore, H₁R gene knockout prevented paw swelling and vascular leakage caused by procaine, tetracaine, and lidocaine in vivo. This study supported a key role of H₁R in LA-induced angioedema, and suggested that in the design of LA structure, the ring formation of the N-methyl scaffold on the side chain can properly avoid the angioedema.

Significant predictive factors of the severity and outcomes of the first attack of acute angioedema in children

Background

The initial episode of angioedema in children can be potential life-threatening due to the lack of prompt identification and treatment. We aimed to analyze the factors predicting the severity and outcomes of the first attack of acute angioedema in children.

Methods

This was a retrospective study with 406 children (< 18 years) who presented in the emergency department (ED) with an initial episode of acute angioedema and who had subsequent follow-up visits in the out-patient department from January 2008 to December 2014. The severity of the acute angioedema was categorized as severe (requiring hospital admission), moderate (requiring a stay in the short-term pediatric observation unit [POU]), or mild (discharged directly from the ED). The associations among the disease severity, patient demographics and clinical presentation were analyzed.

Result

In total, 109 (26.8%) children had severe angioedema, and the majority of those children were male (65.1%). Most of the children were of preschool age (56.4%), and only 6.4% were adolescents. The co-occurrence of pyrexia or urticaria, etiologies of the angioedema related to medications or infections, the presence of respiratory symptoms, and a history of allergies (asthma, allergic rhinitis) were predictors of severe angioedema (all p < 0.05). Finally, the duration of angioedema was significantly shorter in children who had received short-term POU treatment (2.1 ± 1.1 days) than in those who discharged from ED directly (2.3 ± 1.4 days) and admitted to the hospital (3.5 ± 2.0 days) (p < 0.001).

Conclusion

The co-occurrence of pyrexia or urticaria, etiologies related to medications or infections, the presence of respiratory symptoms, and a history of allergies were predictors of severe angioedema. More importantly, short-term POU observation and prompt treatment might be benefit for patients who did not require hospital admission.

Extremely Delayed Diagnosis of Type II Hereditary Angioedema: Case Report and Review of the Literature

We present a case with extremely late diagnosis of type II hereditary angioedema (HAE). Given recent advances in HAE treatment, we want to bring physician awareness to this condition and aid in earlier detection. HAE is a disorder associated with episodes of angioedema of the face, larynx, lips, abdomen, or extremities. Late diagnosis of HAE can lead to significant morbidity and is severely impairing due to recurring attacks. The diagnosis of HAE is ordinarily made during childhood and adolescence. Delayed diagnoses in early and middle adulthood have been documented in the literature. Gastrointestinal symptoms are common features of HAE and can be misdiagnosed as disease of primary gastrointestinal pathology, such as irritable bowel syndrome, recurrent pancreatitis, or appendicitis. These attacks are characterized by recurrent attacks of subcutaneous and submucosal edema without the presence of urticaria.We present a case of an elderly veteran whose diagnoses was extremely delayed into the eighth decade of life subsequent to unexplained abdominal symptoms. After diagnosis, the patient's symptoms were well controlled with medication due to advances in HAE treatment. To prevent further atypically delayed diagnoses, physicians should consider HAE in patients with recurrent attacks of unexplained abdominal pain.

Anaphylaxis

Anaphylaxis is a systemic, life-threatening disorder triggered by mediators released by mast cells and basophils activated via allergic (IgE-mediated) or nonallergic (non-IgE-mediated) mechanisms. It is a rapidly evolving, multisystem process involving the integumentary, pulmonary, gastrointestinal, and cardiovascular systems. Anaphylaxis and angioedema are serious disorders that can lead to fatal airway obstruction and culminate in cardiorespiratory arrest, resulting in hypoxemia and/or shock. Often, these disorders can be appropriately managed in an outpatient setting; however, these conditions can be severe enough to warrant evaluation of the patient in the ED and in some cases, hospitalization, and management in an ICU. Reports suggest that underdiagnosis and undertreatment of anaphylaxis are common. Several new syndromes have been described recently including bird-egg, pork-cat, delayed allergy to mammalian meat and a diverse group of mast cell activation disorders. Conditions such as postural orthostatic tachycardia syndrome, carcinoid syndrome, Munchausen stridor, and factitious anaphylaxis can present similarly and need to be included in the differential diagnosis. Anaphylaxis is a clinical diagnosis, but plasma tryptase and urinary histamine levels are often elevated, allowing diagnostic confirmation; however, diagnostic testing should not delay treatment as results may not be immediately available. The sine qua non of treatment is avoidance of any known triggers and epinephrine, which should never be delayed if this disorder is suspected. Secondary treatments include fluids, bronchodilators, antihistamines, and glucocorticoids. Patients with cardiopulmonary arrest or airway or vascular compromise require mechanical ventilation, vasopressors, and other advanced life support in the ICU.