Peri-operative anaphylaxis

Perioperative Anaphylaxie – alte Zöpfe und Neues zu den Auslösern

Perioperative Anaphylaxien werden mit mindestens 1:6000 angegeben. Neue Kenntnisse der Pathophysiologie der anaphylaktischen Reaktionen beziehen die Auslösung über das Mastzell-related G-Protein und die Komplementaktivierungs-abhängige Pseudoallergie mit ein. Neu beschriebene Auslöser sind das Chlorhexidin oder Gelatine-Produkte, eingesetzt zur Blutstillung oder blaue Farbstoffe zur intraoperativen Markierung. Wachsamkeit ist in Hinblick auf biphasische Reaktionen geboten. Propofol darf mittlerweile bei Ei- und Sojaallergikern eingesetzt werden.

Perioperative Anaphylaxis: Evaluation and Management

Perioperative anaphylaxis (PA) is a rare but life-threatening condition that poses diagnostic and management challenges in the operating room. The incidence of severe perioperative reactions is estimated to be approximately 1:7000-10,000. Management involves both immediate stabilization of the patient and identifying the culprit agent. Identification is essential to prevent recurrence of the event in subsequent surgeries and to avoid unnecessary labeling of drug allergy. Identifying all possible exposures including medications, disinfectants, latex, and dyes and choosing the appropriate tests are essential for proper evaluation. To identify the culprit, primary testing modalities include tryptase at the time of the reaction with subsequent levels and skin testing with nonirritating concentrations to the medications and substances utilized during the procedure and those potentially used as alternates. This strategy provides guidance for future surgeries and procedures. Close collaboration between the allergy, anesthesiology, and surgery teams is essential for appropriate management of these patients at the time of the reaction, during the post event evaluation and in preparation for subsequent surgeries.

Revisiting the role of MRGPRX2 on hypersensitivity reactions to neuromuscular blocking drugs

Anaphylaxis is caused by a variety of triggers including Food and Drug Administration (FDA)-approved antibiotics, contrast media and neuromuscular blocking drugs (NMBDs). Traditionally, drug-induced anaphylaxis was thought to result mainly from IgE-mediated histamine release from mast cells. Recently, a G protein-coupled receptor known as MRGPRX2 has been identified and shown to be highly expressed on human skin but not lung mast cells. The demonstration that many NMBDs induce degranulation in human mast cells via MRGPRX2 led to the idea that this receptor contributes to NMBD-induced hypersensitivity reactions. However, other studies have raised doubts regarding its role in drug-induced hypersensitivity. This review discusses the current status and controversy on MRGPRX2's role on NMBD-induced hypersensitivity.

Perioperative Anaphylaxie – alte Zöpfe und Neues zu den Auslösern

Perioperative Anaphylaxien werden mit mindestens 1:6000 angegeben. Neue Kenntnisse der Pathophysiologie der anaphylaktischen Reaktionen beziehen die Auslösung über das Mastzell-related G-Protein und die Komplementaktivierungs-abhängige Pseudoallergie mit ein. Neu beschriebene Auslöser sind das Chlorhexidin oder Gelatine-Produkte, eingesetzt zur Blutstillung oder blaue Farbstoffe zur intraoperativen Markierung. Wachsamkeit ist in Hinblick auf biphasische Reaktionen geboten. Propofol darf mittlerweile bei Ei- und Sojaallergikern eingesetzt werden.

A Challenge for Allergologist: Application of Allergy Diagnostic Methods in Mast Cell Disorders

Primary and secondary mast cell activation syndromes (MCAS) can occur in patients with mastocytosis. During the past few years our knowledge about the pathogenesis and disease-triggering mechanisms in MCAS and mastocytosis have increased substantially. Whereas mastocytosis is characterized by an accumulation of neoplastic (clonal) mast cells (MC) in various organ systems, MCAS is defined by a massive and systemic activation of these cells. Mast cells are crucial effector cells in allergic diseases, thus their elevated number and activation can cause severe anaphylactic reactions and MCAS in patients with mastocytosis. However, these cells may also degranulate spontaneously or degranulate in response to non-allergic triggers leading to clinical symptoms. In mastocytosis patients, such symptoms may lead to the diagnosis of a primary MCAS. The diagnosis of a concomitant allergy in mastocytosis patients is challenging. In these patients, a mixed form (primary and secondary) of MCAS may be diagnosed. These patients may also suffer from life-threatening anaphylactic reactions when exposed to allergens. In these cases, the possibility of severe side effects of in vivo provocations can sometimes also limit diagnostic evaluations. In the current article, we discuss the diagnosis and management of patients suffering from mastocytosis and concomitant MCAS, with special emphasis on novel diagnostic tests and management, including allergen microarrays, recombinant allergen analysis, basophil activation tests, optimal prophylaxis, and specific therapies.

Perioperative approach of allergic patients

Perioperative allergic reactions are rare, yet important complications of anesthesia. Severe, generalized allergic reactions called anaphylaxis are estimated to have a mortality of 3.5-4.8%. Adequate recognition and handling of a severe perioperative anaphylactic reaction result in better outcomes, including less hypoxic-ischemic encephalopathy and death. The diagnosis of a perioperative allergic reaction can be difficult as the list of possible culprits of a perioperative allergic reaction is extensive. Making an informed guess on the causative agent and avoiding this agent in future anesthesia procedures is undesirable and unsafe. Therefore, to ensure future patient safety, a thorough investigation following a perioperative allergic reaction is mandatory. A collaborate approach by allergists and anesthesiologists is advised. In this article, we discuss the basic approach of the allergic patient and of patients with a suspected allergy to perioperatively administered medication.

Mas-Related G Protein-Coupled Receptor-X2 (MRGPRX2) in Drug Hypersensitivity Reactions

The human ortholog MRGPRX2 and the mice ortholog, Mrgprb2 are activated by basic secretagogues and neurokinins. A number of commonly used small-molecule drugs (e.g., neuromuscular blocking agents, fluoroquinolones, vancomycin) have been recently shown to activate these receptors under in vitro experimental conditions, what results in mast cell degranulation. The above drugs are also known to cause IgE-mediated anaphylactic reactions in allergic patients. The new findings on mechanisms of drug-induced mast cell degranulation may modify the current management of drug hypersensitivity reactions. Clinical interpretation of mild drug-provoked hypersensitivity reactions, interpretation of skin test with a drug of interest or further recommendations for patients suspected of drug allergy are likely to be reconsidered. In the paper we discussed future directions in research on identification and differentiation of MRGPRX2-mediated and IgE-dependent mast cell degranulation in patients presenting clinical features of drug-induced hypersensitivity reactions.

Medication-related anaphylaxis treated in hospital: Agents implicated, patient outcomes, and management lessons

PURPOSE

On background of increasing medication-related anaphylaxis rates in Australia, our aim was to determine epidemiology, outcomes, adverse drug reaction (ADR) reporting rates, and accuracy of coding in patients treated for nonantimicrobial medication-related anaphylaxis in our hospital network.

METHODS

From January 2010 to December 2015 patients treated in our hospital network for medication-related anaphylaxis were identified using International Classification of Diseases, 10th Edition diagnosis code T88.6. Cases were also extracted from the hospital ADR database. Medical records were reviewed to ensure consistent diagnosis and to extract clinical, documentation, and outcome data.

RESULTS

Of 1110 patients coded as T88.6, 177 (15.9%) met the medication-related anaphylaxis definition. Eighty (40.8%) had anaphylaxis due to nonantimicrobial agents. Thirteen of these (16.3%) had a previous reaction to the same medication/group. In 51 (63.8%) patients, anaphylaxis occurred during inpatient stay, with 31 reactions occurring during surgery. Eighty-five medications were implicated, most commonly neuromuscular blocking agents (31, 36.5%) and nonsteroidal anti-inflammatory drugs. No trends were noted over the 6-year period, and there was no anaphylaxis-related mortality. Fifty-three (66.3%) patients were assessed in allergy clinics. One in 10 cases did not have the reaction documented in the discharge summary. Adverse drug reaction reports were received for 38 patients (47.5%).

CONCLUSIONS

Although acute patient outcomes were excellent, gaps in practice were noted regarding ADR coding accuracy and reporting rates. One in 6 patients had a prior hypersensitivity reaction to a similar medication, so we recommend accurate documentation, ADR review with allergy follow-up, and patient held information to decrease re-exposure risk.

Focus on the agents most frequently responsible for perioperative anaphylaxis

Adverse reactions (ARs) to drugs administered during general anesthesia may be very severe and life-threatening, with a mortality rate ranging from 3 to 9%. The adverse reactions to drugs may be IgE and non-IgE-mediated. Neuromuscular blocking agents (NMBA) represent the first cause of perioperative reactions during general anesthesia followed by latex, antibiotics, hypnotic agents, opioids, colloids, dyes and antiseptics (chlorhexidine). All these substances (i.e. NMBA, anesthetics, antibiotics, latex devices) may cause severe systemic non-IgE-mediated reactions or fatal anaphylactic events even in the absence of any evident risk factor in the patient's anamnesis. For this reason, in order to minimize perioperative anaphylactic reactions, it is important to have rapid, specific, sensitive in vitro diagnostic tests able to confirm the clinical diagnosis of acute anaphylaxis.

The Eyes Have It: Eyelid Swelling and Rash in a 79-year-old Woman With Macular Degeneration

Introduction

A 79-year-old woman with macular degeneration was referred to the Allergy/Immunology clinic for the evaluation of a potential allergy to anti-vascular endothelial growth factor (anti-VEGF) treatments. The patient developed urticaria and eyelid swelling immediately following a retinal injection of aflibercept, which she had previously tolerated. She previously had allergic reactions following ranibizumab and bevacizumab injections. Injections of anti-VEGF treatments were discontinued given concern for allergy with progression of the patient’s disease.

Objective

To assess the culprit medication(s) responsible for hypersensitivity reactions following anti-VEGF injections for macular degeneration.

Methods

Medication records were reviewed for each retinal injection. All medications used in each procedure, including the anti-VEGF therapy (aflibercept), topical anesthetics (tetracaine and proparacaine hydrochloride), and antiseptic (povidine), were evaluated with skin testing. She was additionally tested for alternative anti-VEGF therapies (ranibizumab and bevacizumab) as she was thought to have allergies to these agents by prior history. A test dose challenge was completed for aflibercept, ranibizumab, and bevacizumab.

Results

Skin prick and intradermal testing were negative to aflibercept, ranibizumab, bevacizumab, and povidine. Intradermal testing was positive to tetracaine and proparacaine hydrochloride. The patient passed test dose challenges to aflibercept, ranibizumab, and bevacizumab. Due to her positive hypersensitivity testing to 2 ester anesthetics, the patient underwent skin prick and intradermal testing to the amide anesthetic, lidocaine. This was negative and the patient tolerated a graded challenge to lidocaine. She was deemed to have an immunoglobulin E (IgE)-mediated hypersensitivity to ester-type local anesthetics. She successfully resumed anti-VEGF therapy with an amide local anesthetic.

Conclusions

The reason for this consult was the concern for hypersensitivity to a biologic anti-VEGF medication. The culprit allergen, the local anesthetic, could have been overlooked without an assessment of all medications used during the procedure. This case highlights the importance of a thorough allergy evaluation of all medications used during procedures to determine the causative agent.

Chief Complaint: Eyelid swelling and rash after ophthalmic procedures for macular degeneration.

Mrgprs on vagal sensory neurons contribute to bronchoconstriction and airway hyper-responsiveness

Asthma, accompanied by lung inflammation, bronchoconstriction and airway hyper-responsiveness, is a significant public health burden. Here we report that Mas-related G protein-coupled receptors (Mrgprs) are expressed in a subset of vagal sensory neurons innervating the airway and mediates cholinergic bronchoconstriction and airway hyper-responsiveness. These findings provide insights into the neural mechanisms underlying the pathogenesis of asthma.

Anaphylactic Shock During Pediatric Anesthesia: An Unexpected Reaction to Sevoflurane

During general anesthesia, while muscle relaxants, latex and antibiotics are normally considered as very common causes of anaphylactic reactions, there are no documented cases of anaphylaxis due to inhalational agents. We report the case of a 6-year-old child scheduled for adenotonsillectomy who had an anaphylactic shock reaction due to Sevoflurane. Several allergic tests were performed to detect the trigger. Drugs used during operation were tested on both patient and three matched controls. While controls were negative, the patient displayed a positive reaction to Sevoflurane. To our knowledge, this is the first published report describing an allergic reaction caused by a volatile anesthetic.

Perioperative Management of a Patient with Cold Urticaria

Cold urticaria consists of an allergic immune response to cold temperatures with symptoms ranging from pruritic wheals to life-threatening angioedema, bronchospasm, or anaphylactic shock. Adequate planning to maintain normothermia perioperatively is vital due to impaired hypothalamic thermoregulation and overall depression of sympathetic outflow during deep sedation and general anesthesia. This case report describes the successful perioperative management of a 45-year-old female with a history of cold urticaria undergoing a laparoscopic Nissen fundoplication for refractory gastroesophageal reflux disease and discusses how to appropriately optimize the care of these patients.

Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or "Innate Hypersensitivity"?

Approximately 60% of perioperative anaphylactic reactions are thought to be immunoglobulin IgE mediated, whereas 40% are thought to be non-IgE mediated hypersensitivity reactions (both considered non-dose-related type B adverse drug reactions). In both cases, symptoms are elicited by mast cell degranulation. Also, pharmacological reactions to drugs (type A, dose-related) may sometimes mimic symptoms triggered by mast cell degranulation. In case of hypotension, bronchospasm, or urticarial rash due to mast cell degranulation, identification of the responsible mechanism is complicated. However, determination of the type of the underlying adverse drug reaction is of paramount interest for the decision of whether the culprit drug may be re-administered. Neuromuscular blocking agents (NMBA) are among the most frequent cause of perioperative anaphylaxis. Recently, it has been shown that NMBA may activate mast cells independently from IgE antibodies via the human Mas-related G-protein-coupled receptor member X2 (MRGPRX2). In light of this new insight into the patho-mechanism of pseudo-allergic adverse drug reactions, in which as drug-receptor interaction results in anaphylaxis like symptoms, we critically reviewed the literature on NMBA-induced perioperative anaphylaxis. We challenge the dogma that NMBA mainly cause IgE-mediated anaphylaxis via an IgE-mediated mechanism, which is based on studies that consider positive skin test to be specific for IgE-mediated hypersensitivity. Finally, we discuss the question whether MRGPRX2 mediated pseudo-allergic reactions should be re-classified as type A adverse reactions.

Effects of pneumoperitoneum on severe hypernatremia in an adult patient who underwent laparoscopic surgery of hydatid cysts

We describe the first case of severe hypernatremia associated to laparoscopic surgery for hydatid cyst in an adult patient after the use of hypertonic saline solution with complete resolution. Severe hypernatremia is an unusual fact at the immediate postoperative period but may have fatal consequences for the patient and need immediate action. The patient reached a serum sodium concentration of 179 mmol/L without adverse effects after 6 days of treatment. Laparoscopy could play a crucial role in Na⁺ absorption due to high intraabdominal pressure caused by the pneumoperitoneum and its limitations to avoid peritoneal absorption of hypertonic saline solution. The relation between this surgical technique and the severe complication is discussed. More experience is needed in terms of safety for the patient.

Intraoperative medications associated with hemodynamically significant anaphylaxis

STUDY OBJECTIVE

To facilitate the identification of drugs and patient factors associated with hemodynamically significant anaphylaxis.

DESIGN

Using an existing database containing complete perioperative records, instances of hemodynamically significant anaphylaxis were identified using a physiologic and treatment-based screening algorithm. All cases were manually reviewed by 2 clinicians, with a third adjudicating disagreements, and confirmed cases were matched 3:1 with control cases. Intraoperative medications given in instances of hemodynamically significant anaphylaxis and patient risk factors were compared with control cases.

SETTING

University of Michigan Hospital, a large, tertiary care hospital.

PATIENTS

All adult patients undergoing surgery between January 1, 2004, and January 5, 2015.

INTERVENTIONS

None.

MEASUREMENTS

Incidence of hemodynamically significant anaphylaxis during anesthesia. Patient risk factors and intraoperative medications associated with hemodynamically significant anaphylaxis.

MAIN RESULTS

Hemodynamically significant anaphylaxis occurred in 55 of 461 986 cases (1 in 8400). Hemodynamically significant anaphylaxis occurred in 52 patients, with 1 patient experiencing 3 instances and another patient 2 instances. Only 1 drug was associated with an increased risk of hemodynamically significant anaphylaxis: protamine (odds ratio, 11.78; 95% confidence interval, 1.40-99.26; P=.0233). No category of drugs was associated with increased risk. Of patient risk factors, only personal history of anaphylaxis was associated with an increased risk (odds ratio, 77.1; 95% confidence interval, 10.46-567.69; P=<.0001). Postoperative follow-up and evaluation of patients were low at our institution. A serum tryptase level was sent in only 49% of cases, and 41% of levels were positive, an overall positive rate of 20% of cases. Following instances of hemodynamically significant anaphylaxis, only 29% of patients were seen and evaluated by an allergist at our institution.

CONCLUSIONS

Hemodynamically significant anaphylaxis is a rare complication of anesthesia, with an incidence consistent with the existing literature. Contrary to most existing literature, only protamine was associated with increased risk. A personal history of anaphylaxis appears to best predict risk of hemodynamically significant anaphylaxis.

Sugammadex and rocuronium-induced anaphylaxis

Perioperative anaphylaxis is a life-threatening clinical condition that is typically the result of drugs or substances used for anesthesia or surgery. The most common cause of anaphylaxis during anesthesia is reportedly neuromuscular blocking agents. Of the many muscle relaxants that are clinically available, rocuronium is becoming popular in many countries. Recent studies have demonstrated that succinylcholine (but also rocuronium use) is associated with a relatively high rate of IgE-mediated anaphylaxis compared with other muscle relaxant agents. Sugammadex is widely used for reversal of the effects of steroidal neuromuscular blocking agents, such as rocuronium and vecuronium. Confirmed cases of allergic reactions to clinical doses of sugammadex have also been recently reported. Given these circumstances, the number of cases of hypersensitivity to either sugammadex or rocuronium is likely to increase. Thus, anesthesiologists should be familiar with the epidemiology, mechanisms, and clinical presentations of anaphylaxis induced by these drugs. In this review, we focus on the diagnosis and treatment of anaphylaxis to sugammadex and neuromuscular blocking agents. Moreover, we discuss recent studies in this field, including the diagnostic utility of flow cytometry and improvement of rocuronium-induced anaphylaxis with the use of sugammadex.

Immediate-type hypersensitivity drug reactions

Hypersensitivity reactions including anaphylaxis have been reported for nearly all classes of therapeutic reagents and these reactions can occur within minutes to hours of exposure. These reactions are unpredictable, not directly related to dose or the pharmacological action of the drug and have a relatively high mortality risk. This review will focus on the clinical presentation, immune mechanisms, diagnosis and prevention of the most serious form of immediate onset drug hypersensitivity reaction, anaphylaxis. The incidence of drug-induced anaphylaxis deaths appears to be increasing and our understanding of the multiple and complex reasons for the unpredictable nature of anaphylaxis to drugs is also expanding. This review highlights the importance of enhancing our understanding of the biology of the patient (i.e. immune response, genetics) as well as the pharmacology and chemistry of the drug when investigating, diagnosing and treating drug hypersensitivity. Misdiagnosis of drug hypersensitivity leads to substantial patient risk and cost. Although oral provocation is often considered the gold standard of diagnosis, it can pose a potential risk to the patient. There is an urgent need to improve and standardize diagnostic testing and desensitization protocols as other diagnostic tests currently available for assessment of immediate drug allergy are not highly predictive.

Exploring the link between pholcodine exposure and neuromuscular blocking agent anaphylaxis

Neuromuscular blocking agents (NMBAs) are the most commonly implicated drugs in IgE-mediated anaphylaxis during anaesthesia that can lead to perioperative morbidity and mortality. The rate of NMBA anaphylaxis shows marked geographical variation in patients who have had no known prior exposure to NMBAs, suggesting that there may be external or environmental factors that contribute to the underlying aetiology and pathophysiology of reactions. Substituted ammonium ions are shared among NMBAs and are therefore thought to be the main allergenic determinant of this class of drugs. Substituted ammonium ions are found in a wide variety of chemical structures, including prescription medications, over-the-counter medications and common household chemicals, such as the quaternary ammonium disinfectants. Epidemiological studies have shown parallels in the consumption of pholcodine, a nonprescription antitussive drug which contains a tertiary ammonium ion, and the incidence of NMBA anaphylaxis. This link has prompted the withdrawal of pholcodine in some countries, with an ensuing fall in the observed rate of NMBA anaphylaxis. While such observations are compelling in their suggestion of a relationship between pholcodine exposure and NMBA hypersensitivity, important questions remain regarding the mechanisms by which pholcodine is able to sensitize against NMBAs and whether there are other, as yet unidentified, agents that can elicit similar hypersensitivity reactions. This review aims to explore the evidence linking pholcodine exposure to NMBA hypersensitivity and discuss the implications for our understanding of the pathophysiology of these reactions.

Chlorhexidine-induced anaphylaxis in surgical patients: a review of the literature

BACKGROUND

Chlorhexidine (CHL) has antiseptic and disinfectant properties used to prevent hospital-acquired infections. CHL-induced anaphylaxis is poorly reported in surgical literature despite government warnings and growing recognition. The aim of this review is to increase awareness of CHL-induced anaphylaxis in the surgical population.

METHODS

Literature review of Embase, Medline, PubMed and the Cochrane library using 'anaphylaxis (and) chlorhexidine' search terms.

RESULTS

Thirty-six articles were published on surgical patients suffering anaphylaxis to CHL. Within these, seven patients had two proven separate anaphylactic reactions and one had three separate proven anaphylactic reactions. The most commonly affected speciality was urology. The majority occurred during elective procedures. A history of atopy was surprisingly uncommon as was bronchospasm. Six patients required active chest compressions and 39.71% of patients had their surgical procedure abandoned. Unplanned intensive care admissions occurred in 27.94%.

DISCUSSION

In order to reduce abandoned procedures, unplanned intensive care unit admissions, morbidity and mortality associated with CHL-induced anaphylaxis we recommend the following: rationalization of CHL-containing products, greater vigilance regarding subtle symptoms of CHL allergy, appropriate investigation of these symptoms and a greater awareness of CHL-containing products. Lastly, we outline the appropriate investigations and highlight the need for meticulous documentation in those who are CHL allergic.

Perioperative anaphylaxis

BACKGROUND AND OBJECTIVE

Anaphylaxis remains one of the potential causes of perioperative death, being generally unanticipated and quickly progress to a life threatening situation. A narrative review of perioperative anaphylaxis is performed.

CONTENT

The diagnostic tests are primarily to avoid further major events. The mainstays of treatment are adrenaline and intravenous fluids.

CONCLUSION

The anesthesiologist should be familiar with the proper diagnosis, management and monitoring of perioperative anaphylaxis.

[Perioperative anaphylaxis]

BACKGROUND AND OBJECTIVE

Anaphylaxis remains one of the potential causes of perioperative death, being generally unanticipated and quickly progressing to a life-threatening situation. A review of perioperative anaphylaxis is performed.

CONTENT

The diagnostic tests are important mainly to avoid further major events. The mainstays of treatment are adrenaline and intravenous fluids.

CONCLUSION

The anesthesiologist should be familiar with the proper diagnosis, management and monitoring of perioperative anaphylaxis.

Anaphylactic reaction 5 minutes after the start of surgery: a case report

BACKGROUND

Natural latex rubber products have been known to cause severe anaphylactic reactions during surgery. Even 25 years after the first description of anaphylactic reactions in the literature, natural latex rubber products are still used in pediatric surgery.

CASE PRESENTATION

The following article describes the case of a healthy 4.5-year old Caucasian boy who simultaneously developed severe hypotension, tachycardia and bronchospasm during surgery for congenital strabismus sursoadductorius under uneventful anesthesia. An allergy test conducted afterwards showed natural latex rubber as the trigger for this severe intraoperative anaphylactic reaction. This case was special because of the absence of any previous clinical or anamnestical evidence of natural latex rubber allergy. The fact that the child had been previously exposed to natural latex rubber - because the boy's mother used disposable gloves for her work as a cosmetician at home - was only discovered later. Such contact may have had a slight sensitizing effect that manifested after the initial contact with the conjunctiva through the surgeon's natural latex rubber gloves.

CONCLUSION

Natural latex rubber products have caused severe anaphylactic reactions time and again. Diagnosis is impeded by the highly variable clinical symptoms of anaphylaxis, the non-responsivity of patients, anesthesia-induced changes in blood pressure, surgical drapes, and blood loss. Therefore, use of alternative products and implementation of the right course of action in clinical routine seems to be even more important than raising awareness for allergies to natural latex rubber.

Anaesthetic Management of Anaphylactic Shock Caused by Nonruptured Hydatid Cyst of the Liver

Hepatic hydatid cyst (HC) caused by Echinococcus granulosus is still endemic in many parts of the world, and it is a common health problem, especially in developing countries. The rupture of the HC can cause anaphylactic shock or even death during surgical treatment. We present a case report regarding anaphylactic reaction due to surgery to the liver for HC which has an aberrant venous drainage incidentally detected during surgical operation in a 50-year old female patient. She was successfully treated with adrenaline, antihistamines, steroids, colloid or crystalloid fluids. After the surgery, she was transferred from the intensive care unit to the surgical ward on the first postoperative day. The possibility of anaphylaxis should be kept in mind; despite all the precautionary measures, nonrupture of the hydatic cyst and absence of spillage of the cyst to the circulation or into the surrounding tissues, anaphylaxis can still occur. Therefore, close monitoring for early diagnosis and appropriate management of anaphylaxis are essential to stabilize the patient and produce the best outcome.

Nonclinical evaluation of novel cationically modified polysaccharide antidotes for unfractionated heparin

Protamine, the only registered antidote of unfractionated heparin (UFH), may produce a number of adverse effects, such as anaphylactic shock or serious hypotension. We aimed to develop an alternative UFH antidote as efficient as protamine, but safer and easier to produce. As a starting material, we have chosen generally non-toxic, biocompatible, widely available, inexpensive, and easy to functionalize polysaccharides. Our approach was to synthesize, purify and characterize cationic derivatives of dextran, hydroxypropylcellulose, pullulan and γ-cyclodextrin, then to screen them for potential heparin-reversal activity using an in vitro assay and finally examine efficacy and safety of the most active polymers in Wistar rat and BALB/c mouse models of experimentally induced arterial and venous thrombosis. Efficacy studies included the measurement of thrombus formation, activated partial thromboplastin time, bleeding time, and anti-factor Xa activity; safety studies included the measurement of hemodynamic, hematologic and immunologic parameters. Linear, high molecular weight dextran substituted with glycidyltrimethylammonium chloride groups at a ratio of 0.65 per glucose unit (Dex40-GTMAC3) is the most potent and the safest UFH inhibitor showing activity comparable to that of protamine while possessing lower immunogenicity. Cationic polysaccharides of various structures neutralize UFH. Dex40-GTMAC3 is a promising and potentially better UFH antidote than protamine.

Perioperative anaphylactic reactions: Review and procedure protocol in paediatrics

Perioperative anaphylactic reactions are immediate, hypersensitive reactions that are potentially life-threatening resulting from a sudden release of mediators from mast cells and basophiles, due to either immune (IgE or non-IgE mediated) or non-immune mechanisms. The most frequent causing agents are neuromuscular blocking agents (NMBAs), latex and antibiotics, with latex being the first cause in paediatrics. With regard to perioperative anaphylactic reactions, the usual early signs and symptoms of an anaphylactic reaction could be overlooked or erroneously interpreted and non-severe anaphylaxis could go undetected, with a risk of more severe reactions in the future. Using the data registered on the anaesthesia sheet, it is essential to establish a chronological relationship between drugs and/or substances administered and the reaction observed. An elevated level of tryptase confirms an anaphylactic reaction, but this does not usually increase in the absence of compromised circulation. An allergy study should be carried out preferably between 4 and 6 weeks after the reaction, using a combination of specific IgE, skin and controlled exposure tests (if indicated). Test sensitivity is good for NMBAs, latex, antibiotics, chlorhexidine, gelatine and povidone, and poor for barbiturates, opiates (these can give false positives since they are histamine releasers) and benzodiazepines. Special preventive measures should be taken, especially in the case of latex. We present the maximum concentrations recommended for skin tests, the recommended dosage to treat anaphylactic reactions in paediatrics and a procedure algorithm for the allergological study of these reactions.

Identification of a mast-cell-specific receptor crucial for pseudo-allergic drug reactions

Mast cells are primary effectors in allergic reactions, and may have significant roles in diseases by secreting histamine and various inflammatory and immunomodulatory substances^1,2. While classically they are activated by IgE antibodies, a unique property of mast cells is their antibody-independent responsiveness to a range of cationic substances, collectively called basic secretagogues, including inflammatory peptides and drugs associated with allergic-type reactions^1,3. Roles for these substances in pathology have prompted a decades-long search for their receptor(s). Here we report that basic secretagogues activate mouse mast cells in vitro and in vivo through a single receptor, MrgprB2, the orthologue of the human G-protein coupled receptor (GPCR) MrgprX2. Secretagogue-induced histamine release, inflammation, and airway contraction are abolished in MrgprB2 null mutant mice. Further, we show that most classes of FDA-approved peptidergic drugs associated with allergic-type injection-site reactions also activate MrgprB2 and MrgprX2, and that injection-site inflammation is absent in mutant mice. Finally, we determine that MrgprB2 and MrgprX2 are targets of many small molecule drugs associated with systemic pseudo-allergic, or anaphylactoid, reactions; we show that drug-induced symptoms of anaphylactoid responses are significantly reduced in knockout mice, and we identify a common chemical motif in several of these molecules that may help predict side effects of other compounds. These discoveries introduce a mouse model to study mast cell activation by basic secretagogues and identify MrgprX2 as a potential therapeutic target to reduce a subset of drug-induced adverse effects.

Effects of anesthetics on the renal sympathetic response to anaphylactic hypotension in rats

The autonomic nervous system plays an important role in rat anaphylactic hypotension. It is well known that sympathetic nerve activity and cardiovascular function are affected by anesthetics. However, the effects of different types of anesthesia on the efferent renal sympathetic nerve activity (RSNA) during anaphylactic hypotension remain unknown. Therefore, we determined the renal sympathetic responses to anaphylactic hypotension in anesthetized and conscious rats and the roles of baroreceptors in these responses. Sprague-Dawley rats were randomly allocated to anesthetic groups that were given pentobarbital, urethane, or ketamine-xylazine and to a conscious group. The rats were sensitized using subcutaneously injected ovalbumin. The systemic arterial pressure (SAP), RSNA and heart rate (HR) were measured. The effects of sinoaortic baroreceptor denervation on RSNA during anaphylaxis were determined in pentobarbital-anesthetized and conscious rats. In all of the sensitized rats, the RSNA increased and SAP decreased after antigen injection. At the early phase within 35 min of the antigen injection, the antigen-induced sympathoexcitation in the conscious rats was significantly greater than that in the anesthetized rats. Anaphylactic hypotension was attenuated in the conscious rats compared to the anesthetized rats. The anesthetic-induced suppression of SAP and RSNA was greater in the order ketamine-xylazine >urethane = pentobarbital. Indeed, in the rats treated with ketamine-xylazine, RSNA did not increase until 40 min, and SAP remained at low levels after the antigen injection. The baroreceptor reflex, as evaluated by increases in RSNA and HR in response to the decrease in SAP induced by sodium nitroprusside (SNP), was suppressed in the anesthetized rats compared with the conscious rats. Consistent with this finding, baroreceptor denervation attenuated the excitatory responses of RSNA to anaphylaxis in the conscious rats but not in the pentobarbital-anesthetized rats. RSNA was increased markedly in conscious rats during anaphylactic hypotension. Anesthetics attenuated this antigen-induced renal sympathoexcitation through the suppression of baroreceptor function.

[Anaphylactic shock lasting 4 days]

We present a case of a 62 year-old male scheduled for radical cystectomy, who, ten minutes into the surgery, presented with severe hypotension, tachycardia and increased airway pressure. There was no response to the administration of vasoactive drugs such as, ephedrine, phenylephrine, dopamine and norepinephrine. After ruling out several causes, we evaluated the possibility of an anaphylactic reaction. Adrenaline was given, and the patient stabilized. An adrenaline infusion and mechanical ventilation was required for four days in the critical care unit.

Spinal cystic echinococcosis--a systematic analysis and review of the literature: part 2. Treatment, follow-up and outcome

Bone involvement in human cystic echinococcosis (CE) is rare, but affects the spine in approximately 50% of cases. Despite significant advances in diagnostic imaging techniques, surgical treatment and introduction of pharmacological therapy, spinal echinococcosis remains associated with a high degree of morbidity, disability and mortality. We systematically reviewed the published literature of the last five decades to update and summarize the currently existing data on treatment, follow-up and outcome of spinal CE.

Anaphylactic reactions after cisatracurium administration in two patients -a report of two cases-

Cisatracurium was initially characterized to have no evident histamine-releasing potential with excellent cardiovascular stability. However, severe anaphylactic reactions to cisatracurium that resulted in bronchospasms and cardiovascular collapse have been reported worldwide. Two cases of severe anaphylactic reactions after the administration of cisatracurium are presented. The anesthetics used in both cases were lidocaine, midazolam, propofol (microemulsion propofol in the second case), remifentanil and cisatracurium. After the administration of these drugs, bronchospasm and hypotension manifested, leading to the diagnosis of anaphylaxis and appropriate treatment. Skin intradermal testing confirmed that both cases were due to immune-mediated anaphylaxis to cisatracurium, despite the fact that neither of the patients had been exposed to the allergen previously. The anaphylaxis may be due to cross-reactivity between neuromuscular blocking agents and substances with quaternary ammonium ions. Anesthesiologists should be aware that cisatracurium has the potential to trigger severe anaphylactic reactions via an immune-mediated mechanism.