[Treatment of hypersensitivity reactions and anaphylactic shock occurring during anaesthesia]

Neuromuscular blocking agent induced hypersensitivity reaction exploration: an update

Acute hypersensitivity reactions (AHRs) occurring in present-day anaesthesia can have severe, sometimes fatal, consequences and their incidence is increasing. The most frequent allergens responsible for AHR during anaesthesia are neuromuscular blocking agents (NMBAs) (70% of the cases) followed by antibiotics (18%), patent blue dye and methylene blue dye (5%), and latex (5%). Following an AHR, strategies for subsequent anaesthetic procedures (especially the choice of an NMBA) may be difficult to formulate due to inconclusive diagnostic analysis in up to 30% of AHRs. Current diagnosis of AHR relies on the detection of mast cell degranulation products and drug-specific type E immunoglobulins (IgE) in order to document an IgE-mediated anaphylaxis (IgE endotype). Nonetheless, other IgE-independent pathways can be involved in AHR, but their detection is not currently available in standard situations. The different mechanisms (endotypes) involved in peri-operative AHR may contribute to the inconclusive diagnostic work-up and this generates uncertainty concerning the culpable drug and strategy for subsequent anaesthetic procedures. This review provides details on the IgE endotype; an update on non-IgE related endotypes and the novel diagnostic tools that could characterise them. This detailed update is intended to provide explicit clinical reasoning tools to the anaesthesiologist faced with an incomplete AHR diagnostic work-up and to facilitate the decision-making process regarding anaesthetic procedures following an AHR to NMBAs.

Clinical reasoning in anaphylactic shock: addressing the challenges faced by anaesthesiologists in real time: A clinical review and management algorithms

Acute hypersensitivity reactions to drugs occur infrequently during anaesthesia and the peri-operative period. When clinical presentation includes the classical triad, erythema, cardiovascular abnormalities and increased airway pressure, the diagnosis is evident and the challenge is to prescribe a therapeutic regimen according to guidelines and to manage refractory signs in a timely manner. In many situations, however, the initial clinical signs are isolated, such as increased airway pressure or arterial hypotension. Rendering a differential diagnosis with causes and mechanisms other than acute hypersensitivity reactions (AHRs) is difficult, delaying treatment with possible worsening of the clinical signs, and even death, in previously healthy individuals. In these difficult diagnostic situations, clinical reasoning is mandatory, and guidelines do not explicitly explain the elements on which clinical reasoning can be built. In this article, based on clinical evidence whenever available, experimental data and pathophysiology, we propose algorithms that have been evaluated by experts. The goal of these algorithms is to provide explicit elements on which the differential diagnosis of AHRs can be made, accelerating the implementation of adequate therapy.

Platelets expressing IgG receptor FcγRIIA/CD32A determine the severity of experimental anaphylaxis

Platelets are key regulators of vascular integrity; however, their role in anaphylaxis, a life-threatening systemic allergic reaction characterized by the loss of vascular integrity and vascular leakage, remains unknown. Anaphylaxis is a consequence of inappropriate cellular responses triggered by antibodies to generally harmless antigens, resulting in a massive mediator release and rapidly occurring organ dysfunction. Human platelets express receptors for immunoglobulin G (IgG) antibodies and can release potent mediators, yet their contribution to anaphylaxis has not been previously addressed in mouse models, probably because mice do not express IgG receptors on platelets. We investigated the contribution of platelets to IgG-dependent anaphylaxis in human IgG receptor-expressing mouse models and a cohort of patients suffering from drug-induced anaphylaxis. Platelet counts dropped immediately and markedly upon anaphylaxis induction only when they expressed the human IgG receptor FcγRIIA/CD32A. Platelet depletion attenuated anaphylaxis, whereas thrombocythemia substantially worsened its severity. FcγRIIA-expressing platelets were directly activated by IgG immune complexes in vivo and were sufficient to restore susceptibility to anaphylaxis in resistant mice. Serotonin released by activated platelets contributed to anaphylaxis severity. Data from a cohort of patients suffering from drug-induced anaphylaxis indicated that platelet activation was associated with anaphylaxis severity and was accompanied by a reduction in circulating platelet numbers. Our findings identify platelets as critical players in IgG-dependent anaphylaxis and provide a rationale for the design of platelet-targeting strategies to attenuate the severity of anaphylactic reactions.

[Cardiac arrest during liver hydatid cyst surgery]

L'hydatidose est une pathologie fréquente qui reste encore endémique au Maroc. Sa localisation privilégiée est le foie. Son traitement repose essentiellement sur la chirurgie. Celui-ci est parfois incriminé dans la survenue de réactions allergiques sévères pouvant menacer le pronostic vital. Nous rapportons un nouveau cas de réaction anaphylactique sévère de grade IV peropératoire au cours d'une chirurgie de kystes hydatiques multiples du foie. Nous insistons sur la nécessité de sa reconnaissance rapide afin d'instaurer rapidement un traitement efficace. La prévention de cet accident est basée sur des précautions chirurgicales pour éviter les fuites ou les ruptures accidentelles peropératoires des kystes hydatiques.

Optimal perioperative management of arterial blood pressure

Perioperative blood pressure management is a key factor of patient care for anesthetists, as perioperative hemodynamic instability is associated with cardiovascular complications. Hypertension is an independent predictive factor of cardiac adverse events in noncardiac surgery. Intraoperative hypotension is one of the most encountered factors associated with death related to anesthesia. In the preoperative setting, the majority of antihypertensive medications should be continued until surgery. Only renin-angiotensin system antagonists may be stopped. Hypertension, especially in the case of mild to moderate hypertension, is not a cause for delaying surgery. During the intraoperative period, anesthesia leads to hypotension. Hypotension episodes should be promptly treated by intravenous vasopressors, and according to their etiology. In the postoperative setting, hypertension predominates. Continuation of antihypertensive medications and postoperative care may be insufficient. In these cases, intravenous antihypertensive treatments are used to control blood pressure elevation.

Perioperative anaphylaxis

Perioperative anaphylaxis is a life-threatening condition with an estimated prevalence of 1:3,500 to 1:20,000 procedures and a mortality rate of up to 9 %. Clinical presentation involves signs such as skin rash, urticaria, angioedema, bronchospasm, tachycardia, bradycardia, and hypotension. Prompt recognition and treatment is of utmost importance to the patient's prognosis, since clinical deterioration can develop rapidly. Epinephrine is the main treatment drug, and its use should not be postponed, since delayed administration is associated with increased mortality. Elevated levels of serum tryptase help to confirm the diagnosis. The main agents involved in IgE-mediated perioperative anaphylaxis are neuromuscular blocking agents, latex, antibiotics, hypnotics, opioids, and colloids. Specific investigation should be conducted 4 to 6 weeks after the reaction and relies on skin tests, serum-specific IgE, and challenge procedures. This review aims to discuss the main aspects of perioperative anaphylaxis: risk factors, diagnosis, treatment, culprit agents, specific investigation, and preventive measures.

Fatal anaphylaxis with neuromuscular blocking agents: a risk factor and management analysis

BACKGROUND

Anaphylactic reactions to neuromuscular blocking agents (NMBAs) can be severe and even fatal. Our aim was to evaluate mortality rate in France from anaphylactic reactions to NMBAs, to identify risk factors for a fatal outcome, and to describe management of the cases that proved fatal.

METHODS

The French National Pharmacovigilance Database was queried for reports of NMBA anaphylaxis that occurred between January 2000 and December 2011. A questionnaire was sent to regional pharmacovigilance centers to obtain further information on the management of cases with a fatal outcome.

RESULTS

Two thousand and twenty-two cases of NMBA hypersensitivity were retrieved, of which 84 were fatal (4.1%). Among the 1247 cases of severe NMBA anaphylaxis (grades 3 and 4), independent risk factors associated with a fatal outcome in a multivariate analysis were male gender (female gender: OR = 0.4; 95% CI 0.2-0.7; P = 0.0004), an emergency setting (OR = 2.6; 95% CI 1.5-4.6; P = 0.0007), a history of hypertension (OR = 2.5; 95% CI 1.5-4.4; P = 0.0010) or of other cardiovascular disease (OR = 4.4; 95% CI 2.4-8.1; P < 0.0001), obesity (OR = 2.4; 95% CI 1.1-5.3; P = 0.0376), and ongoing beta-blocker treatment (OR = 4.2; 95% CI 1.8-9.8; P = 0.0011). All 31 patients with a fatal outcome received epinephrine in a titrated manner according to international guidelines.

CONCLUSION

Obese males with a history of cardiovascular disease receiving ongoing beta-blocker treatment and undergoing surgery in an emergency setting were at high risk of a fatal outcome after NMBA-induced anaphylaxis. Some epinephrine-resistant cases may play a role in our high mortality rate. New therapeutic approaches need to be developed to treat these cases.

Atypical intraoperative anaphylactic shock with ECG changes secondary to non-ruptured hepatic hydatid cyst

A 62-year-old woman was admitted to the hospital for removal of hydatid cyst from the liver. Intraoperatively, the patient suddenly became hypotensive with tachycardia and ST segment elevation. There was no erythema, bronchospasm or desaturation. Anaesthetic agents were stopped and oxygen fraction was increased. In view of the recurrence of hypotension, she was admitted to the intensive care unit (ICU) without completion of surgery. She was successfully resuscitated and acute myocardial infarction was ruled out. She was managed for the possibility of anaphylaxis with hydration, dopamine, antihistamin and hydrocortisone. After stabilisation, she was taken back to the theatre and the cyst was then removed. Histopathology confirmed hydatid disease of the liver. The patient was discharged from the ICU and then from the hospital in 6 days. Anaphylaxis secondary to hydatid disease is uncommon; however, the possibility of such a diagnosis in all patients with non-ruptured hydatid disease in the endemic areas that develop intraoperative shock should be considered.

Anaphylaxis

PURPOSE OF REVIEW

This article aims to make a review of the up-to-date knowledge on anaphylaxis and outline the recent advances on pathophysiology, diagnosis, and management of anaphylaxis.

RECENT FINDINGS

New data confirm the increase in prevalence of anaphylaxis and emphasize immunopathologic mechanisms. However, anaphylaxis is often underdiagnosed and guidelines are poorly applied, particularly in emergency departments.

SUMMARY

An improvement of rapid diagnosis and treatment combined with education of population will decrease mortality and morbidity of anaphylaxis.

Anaphylactic shock during hydatid cyst surgery

Intraoperative anaphylactic shock is an unusual complication. Different causes can be involved. Surgery of hydatid cyst is rarely responsible. About a case report of anaphylactic shock due to hydatid cyst surgery, the authors discuss the mechanisms, principles of treatment, and prevention measures of this complication.