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.

Mastocytosis and Mast Cell Activation Disorders: Clearing the Air.

Mast cells are derived from hematopoietic stem cell precursors and are essential to the genesis and manifestations of the allergic response. Activation of these cells by allergens leads to degranulation and elaboration of inflammatory mediators, responsible for regulating the acute dramatic inflammatory response seen. Mast cells have also been incriminated in such diverse disorders as malignancy, arthritis, coronary artery disease, and osteoporosis. There has been a recent explosion in our understanding of the mast cell and the associated clinical conditions that affect this cell type. Some mast cell disorders are associated with specific genetic mutations (such as the D816V gain-of-function mutation) with resultant clonal disease. Such disorders include cutaneous mastocytosis, systemic mastocytosis (SM), its variants (indolent/ISM, smoldering/SSM, aggressive systemic mastocytosis/ASM) and clonal (or monoclonal) mast cell activation disorders or syndromes (CMCAS/MMAS). Besides clonal mast cell activations disorders/CMCAS (also referred to as monoclonal mast cell activation syndromes/MMAS), mast cell activation can also occur secondary to allergic, inflammatory, or paraneoplastic disease. Some disorders are idiopathic as their molecular pathogenesis and evolution are unclear. A genetic disorder, referred to as hereditary alpha-tryptasemia (HαT) has also been described recently. This condition has been shown to be associated with increased severity of allergic and anaphylactic reactions and may interact variably with primary and secondary mast cell disease, resulting in complex combined disorders. The role of this review is to clarify the classification of mast cell disorders, point to molecular aspects of mast cell signaling, elucidate underlying genetic defects, and provide approaches to targeted therapies that may benefit such patients.

Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators, Endothelial Gap Junctions and Beyond.

Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC4, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.

Angioedema.

OBJECTIVES: Angioedema is a potentially life-threatening occurrence that is encountered by critical care providers. The mechanistic understanding of angioedema syndromes has improved in recent years, and novel medications are available that improve outcomes from these syndromes. This clinically focused review will describe the underlying genetics, pathophysiology, classification and treatment of angioedema syndromes, with an emphasis on the novel pharmacologic agents that have recently become available for acute treatment. DATA SOURCES: A MEDLINE search was conducted with the MeSH terms angioedema, acquired angioedema, hereditary angioedema type III, and angiotensin converting enzyme inhibitor-induced angioedema. STUDY SELECTION: Selected publications describing angioedema, clinical trials, diagnosis, management, and genetics 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: The data obtained were used to describe the current state of diagnosis and management of various angioedema syndromes. CONCLUSIONS: Angioedema is a life-threatening syndrome with multiple subtypes, each with a distinct pathophysiology. We present an evidence-based approach to the diagnosis and suggested management of various subtypes of angioedema. Securing the airway remains the most important intervention, followed by administration of both established and more novel pharmacologic interventions based on disease pathology.

Hereditary Angioedema: Implications of Management.

Hereditary angioedema (HAE) is a genetic condition that is characterized by frequent episodes of localized angioedema. It is a rare disorder that a primary care provider, otolaryngologist, dermatologist, or rheumatologist may encounter only occasionally. This disease is being reviewed because of the significant advances in further understanding the genetics, biology, and therapeutic management surrounding the condition. Histamine-mediated angioedema responds to steroids, antihistamines, and epinephrine, whereas bradykinin-mediated angioedema is resistant to those interventions and requires specialized therapy. Previously used medications have significant adverse effects. Approved medications for HAE have been effective in decreasing morbidity and mortality in patients with this condition. We review the presentation, diagnosis, and available pharmaceutical options for HAE and explore the limitations of implementing recommended therapy.

Glatiramer acetate-induced lobular panniculitis and skin necrosis.

Glatiramer acetate (GA) is a drug that commonly is used for the treatment of relapsing-remitting multiple sclerosis (RRMS). Although it typically is known as a safe and effective therapy, a number of adverse effects associated with GA have been reported in the literature. Local injection-site reactions (LISRs) and mild systemic symptoms are among the most commonly described adverse effects. A review of the literature revealed limited reports of panniculitis as an adverse effect of GA injection and even fewer describing associated skin necrosis. We report a case of GA-induced panniculitis and skin necrosis and discuss the occurrence of panniculitis, necrosis, and lipoatrophy following GA injections.

Remission of severe aphthous stomatitis of celiac disease with etanercept.

Celiac disease is a common autoimmune disease triggered by gluten-containing foods (wheat, barley and rye) in genetically predisposed individuals. We present a patient with celiac disease complicated by severe aphthous stomatitis resulting in impairing swallowing, chewing and speaking. This led to weight loss, psychosocial problems as well as inability to perform her work. A variety of topical and systemic medications used resulted in either no improvement or only partial alleviation of the patient's symptoms. After informed consent, etanercept was initiated and resulted in complete remission of aphthous stomatitis, decrease in arthralgia and fatigue and considerable improvement in her quality of life. The use of newer biological agents for selected and severe manifestations of celiac disease may lead to improved morbidity in these patients, but more studies are needed to determine long-term efficacy as well as safety of these drugs in the mucosal and/or systemic complications of this disease.

Anaphylactic reactions to oligosaccharides in red meat: a syndrome in evolution.

OBJECTIVE: While most allergic responses to food are directed against protein epitopes and occur within 30 minutes of ingesting the allergen, recent studies suggest that delayed reactions may occur, sometimes mediated by IgE antibodies directed against carbohydrate moieties. The objective of this review is to summarize the clinical features and management of delayed hypersensitivity reactions to mammalian meat mediated by IgE antibodies to galactose-alpha 1,3-galactose (alpha-gal), an oligosaccharide. METHODS: A PubMed search was conducted with MeSH terms: galactosyl-(1,3) galactose, oligosaccharides, cetuximab, allergy/hypersensitivity, and anaphylaxis. Reported cases with alpha-gal-mediated reactions were reviewed. This research study was approved by the Institutional Review Board of East Tennessee State University. RESULTS: Thirty-two cases of adults presenting with red-meat induced allergy thought to be related to oligosaccharides have been reported in the literature so far, making this a rare and evolving syndrome. Most of these patients demonstrated delayed reactions to beef, as was seen in the case reported by us in this manuscript. IgE specific to alpha-gal was identified in most patients with variable response to skin testing with beef and pork. Inhibition studies in some cases showed that the IgE antibodies to beef were directed towards alpha-gal in the meat rather than the protein. The patients often reported history of tick bites, the significance of which is unclear at present. Reactions to cetuximab, a monoclonal antibody, are mediated by a similar mechanism, with IgE antibodies directed against an alpha-gal moiety incorporated in the drug structure. CONCLUSION: Alpha-gal is an oligosaccharide recently incriminated in delayed anaphylactic reactions to mammalian meats such as to beef, pork, and lamb. It appears that anaphylactic reactions to the anti-cancer biological agent, cetuximab, may be linked mechanistically to the same process. More studies are required to understand the underlying molecular basis for these delayed reactions in specific, and their broader implications for host defense in general.

Enhanced effects of cigarette smoke extract on inflammatory cytokine expression in IL-1ß-activated human mast cells were inhibited by Baicalein via regulation of the NF-κB pathway.

BACKGROUND: Human mast cells are capable of a wide variety of inflammatory responses and play a vital role in the pathogenesis of inflammatory diseases such as allergy, asthma, and atherosclerosis. We have reported that cigarette smoke extract (CSE) significantly increased IL-6 and IL-8 production in IL-1ß-activated human mast cell line (HMC-1). Baicalein (BAI) has anti-inflammatory properties and inhibits IL-1ß- and TNF-α-induced inflammatory cytokine production from HMC-1. The goal of the present study was to examine the effect of BAI on IL-6 and IL-8 production from CSE-treated and IL-1ß-activated HMC-1. METHODS: Main-stream (Ms) and Side-stream (Ss) cigarette smoke were collected onto fiber filters and extracted in RPMI-1640 medium. Two ml of HMC-1 at 1 × 106 cells/mL were cultured with CSE in the presence or absence of IL-1ß (10 ng/mL) for 24 hrs. A group of HMC-1 cells stimulated with both IL-1ß (10 ng/ml) and CSE was also treated with BAI. The expression of IL-6 and IL-8 was assessed by ELISA and RT-PCR. NF-κB activation was measured by electrophoretic mobility shift assay (EMSA) and IκBα degradation by Western blot. RESULTS: Both Ms and Ss CSE significantly increased IL-6 and IL-8 production (p < 0.001) in IL-1ß-activated HMC-1. CSE increased NF-κB activation and decreased cytoplasmic IκBα proteins in IL-1ß-activated HMC-1. BAI (1.8 to 30 µM) significantly inhibited production of IL-6 and IL-8 in a dose-dependent manner in IL-1ß-activated HMC-1 with the optimal inhibition concentration at 30 µM, which also significantly inhibited the enhancing effect of CSE on IL-6 and IL-8 production in IL-1ß-activated HMC-1. BAI inhibited NF-κB activation and increased cytoplasmic IκBα proteins in CSE-treated and IL-1ß-activated HMC-1. CONCLUSIONS: Our results showed that CSE significantly increased inflammatory cytokines IL-6 and IL-8 production in IL-1ß-activated HMC-1. It may partially explain why cigarette smoke contributes to lung and cardiovascular diseases. BAI inhibited the production of inflammatory cytokines through inhibition of NF-κB activation and IκBα phosphorylation and degradation. This inhibitory effect of BAI on the expression of inflammatory cytokines induced by CSE suggests its usefulness in the development of novel anti-inflammatory therapies.