Emergency treatment of anaphylaxis in adults - Royal College of ...
Emergency treatment of anaphylaxis in adults - Royal College of ...
Emergency treatment of anaphylaxis in adults - Royal College of ...
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Sett<strong>in</strong>g higher standards<strong>Emergency</strong> <strong>treatment</strong> <strong>of</strong><strong>anaphylaxis</strong> <strong>in</strong> <strong>adults</strong>Concise guidance to good practice seriesApril 2009
■ CONCISE GUIDELINES<strong>Emergency</strong> <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> <strong>in</strong> <strong>adults</strong>:concise guidanceJasmeet Soar on behalf <strong>of</strong> the multidiscipl<strong>in</strong>ary Guidel<strong>in</strong>e Development Group*ABSTRACT – Anaphylaxis is a severe, life-threaten<strong>in</strong>g,generalised or systemic hypersensitivityreaction characterised by rapidly develop<strong>in</strong>g lifethreaten<strong>in</strong>gairway, breath<strong>in</strong>g and/or circulationproblems usually associated with sk<strong>in</strong> and mucosalchanges. Updated guidance on the recognition,acute management and follow up <strong>of</strong> <strong>adults</strong> with<strong>anaphylaxis</strong> has recently been published. This is aconcise version <strong>of</strong> the full guidel<strong>in</strong>es published bythe Resuscitation Council (UK) <strong>in</strong> 2008. The use <strong>of</strong>an airway, breath<strong>in</strong>g, circulation, disability andexposure approach to recognise and treat<strong>anaphylaxis</strong> is emphasised.KEY WORD: <strong>anaphylaxis</strong>Introduction and aimsAnaphylaxis is a severe, life-threaten<strong>in</strong>g hypersensitivityreaction which is estimated to affect approximately1 <strong>in</strong> 1,333 <strong>of</strong> the English population at somepo<strong>in</strong>t <strong>in</strong> their lives. The <strong>in</strong>cidence <strong>of</strong> <strong>anaphylaxis</strong> is<strong>in</strong>creas<strong>in</strong>g and there has been a dramatic growth <strong>in</strong>the rate <strong>of</strong> related hospital admissions <strong>in</strong> the last twodecades. Although the overall prognosis <strong>of</strong> <strong>anaphylaxis</strong>is good (case-fatality ratio <strong>of</strong> less than 1%), therisk <strong>of</strong> death is <strong>in</strong>creased <strong>in</strong> those with pre-exist<strong>in</strong>gasthma. There are approximately 20 deaths due to<strong>anaphylaxis</strong> reported each year <strong>in</strong> the UK.Anaphylaxis can occur follow<strong>in</strong>g exposure to avery broad range <strong>of</strong> triggers (Table 1). It has a range<strong>of</strong> possible presentations and the lack <strong>of</strong> any consistentcl<strong>in</strong>ical manifestations cont<strong>in</strong>ues to cause diagnosticdifficulty. Full guidance for the emergency<strong>treatment</strong> <strong>of</strong> anaphylactic reactions has recently beenpublished. 1 Information <strong>in</strong> this concise guidance hasbeen extracted from the full guidel<strong>in</strong>e. Please refer tothe full guidance for details <strong>of</strong> methodology.The aim <strong>of</strong> this guidance is to provide updated* This guidance was prepared on behalf <strong>of</strong> the multidiscipl<strong>in</strong>aryGuidel<strong>in</strong>e Development Group (GDG)convened by the Work<strong>in</strong>g Group <strong>of</strong> the ResuscitationCouncil (UK) <strong>in</strong> association with the Cl<strong>in</strong>icalEffectiveness and Evaluation Unit <strong>of</strong> the <strong>Royal</strong> <strong>College</strong><strong>of</strong> Physicians. For membership <strong>of</strong> the GDG, see theend <strong>of</strong> paper.recommendations <strong>in</strong> the follow<strong>in</strong>g areas:• the recognition and correct diagnosis <strong>of</strong><strong>anaphylaxis</strong>• the acute management and effective <strong>treatment</strong><strong>of</strong> an anaphylactic reaction <strong>in</strong> <strong>adults</strong>• the appropriate <strong>in</strong>vestigation and follow up <strong>of</strong>patients with suspected <strong>anaphylaxis</strong>.Pathophysiological consequences <strong>of</strong><strong>anaphylaxis</strong>Anaphylaxis can be caused by allergic and nonallergicmechanisms. Allergic <strong>anaphylaxis</strong> is causedby an immediate (type I) hypersensitivity reactionfollow<strong>in</strong>g exposure to an allergen to which thepatient has become sensitised. The allergen stimulatesIgE-mediated degranulation <strong>of</strong> mast cells,releas<strong>in</strong>g large quantities <strong>of</strong> histam<strong>in</strong>e <strong>in</strong>to the circulationwhich causes <strong>in</strong>tense smooth muscle contraction,<strong>in</strong>creased vascular permeability and vasodilation.The cl<strong>in</strong>ical presentation is the same regardless<strong>of</strong> whether the reaction has an allergic or nonallergicmechanism.Adrenal<strong>in</strong>e is the most important drug for the<strong>treatment</strong> <strong>of</strong> an anaphylactic reaction. Failure to<strong>in</strong>ject adrenal<strong>in</strong>e promptly <strong>in</strong>creases the risk <strong>of</strong>death. Adverse effects <strong>of</strong> adrenal<strong>in</strong>e are extremelyJasmeet SoarFRCA, Consultant <strong>in</strong>Anaesthetics andIntensive CareMedic<strong>in</strong>e, NorthBristol NHS TrustConcise Guidanceto Good PracticeSeries Editors:Lynne Turner-Stokes FRCP andBernard Higg<strong>in</strong>sFRCPGuest Editor:Tabitha Turner-Stokes BA MBBSCl<strong>in</strong> Med2009;9:000Table 1. Allergens known to trigger fatal anaphylactic reactions.For further details, please see the full guidance document. 1AllergenSt<strong>in</strong>gsNutsOther foodsAntibioticsAnaesthetic drugs(mostly muscle relaxants)ExamplesWasp, beePeanuts, walnuts, almonds, brazil nuts, hazelnutsMilk, fish, chickpeas, crustaceansPenicill<strong>in</strong>, cephalospor<strong>in</strong>, amphoteric<strong>in</strong>,cipr<strong>of</strong>loxac<strong>in</strong>, vancomyc<strong>in</strong>Suxamethonium, vecuronium, atracuriumOther drugs NSAID, ACEI, gelat<strong>in</strong>s, protam<strong>in</strong>e, vitam<strong>in</strong> K,local anaesthetics, diamorph<strong>in</strong>e, streptok<strong>in</strong>aseContrast mediaIod<strong>in</strong>e, technetium, fluoresce<strong>in</strong>OthersLatex, hair dye, hydatidACEI = angiotens<strong>in</strong> convert<strong>in</strong>g enzyme <strong>in</strong>hibitor; NSAID = non-steroidal anti-<strong>in</strong>flammatorydrug.Cl<strong>in</strong>ical Medic<strong>in</strong>e Vol 9 No 2 April 2009 1© <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Physicians, 2009. All rights reserved.
Jasmeet Soarrare when the correct doses are <strong>in</strong>jected <strong>in</strong>tramuscularly.Intravenous adrenal<strong>in</strong>e has a much greater risk <strong>of</strong> caus<strong>in</strong>gharmful side effects and hence should only be used by thoseexperienced <strong>in</strong> the use and titration <strong>of</strong> vasopressors <strong>in</strong> theirnormal cl<strong>in</strong>ical practice.Recognition <strong>of</strong> an anaphylactic reactionBox 1. Recognition <strong>of</strong> an anaphylactic reaction.Anaphylaxis is likely when all <strong>of</strong> the follow<strong>in</strong>g three criteria are present:1 sudden onset and rapid progression <strong>of</strong> symptoms2 life-threaten<strong>in</strong>g compromise <strong>of</strong>:• airway and/or• breath<strong>in</strong>g and/or• circulation3 sk<strong>in</strong> and/or mucosal changes, for example:• flush<strong>in</strong>g• urticaria• angioedema.Box 2. Symptoms and signs <strong>of</strong> <strong>anaphylaxis</strong>.Airway problems(life-threaten<strong>in</strong>g)Breath<strong>in</strong>g problems(life-threaten<strong>in</strong>g)Circulation problems(life-threaten<strong>in</strong>g)Patients may develop:• swell<strong>in</strong>g <strong>of</strong> tongue or throat (pharyngeal/laryngeal oedema) lead<strong>in</strong>g to difficulty <strong>in</strong>breath<strong>in</strong>g and swallow<strong>in</strong>g• stridor (<strong>in</strong>spiratory noise caused by upperairway obstruction)• hoarse voice.Patients may develop:• shortness <strong>of</strong> breath (<strong>in</strong>creased respiratory rate)• wheeze• exhaustion due to the work <strong>of</strong> breath<strong>in</strong>g• confusion caused by hypoxia• cyanosis (a late sign)• respiratory arrest.Patients may develop:• signs <strong>of</strong> shock (pale, clammy)• tachycardia• hypotension (caus<strong>in</strong>g dizz<strong>in</strong>ess or collapse)• decrease conscious level or loss <strong>of</strong>consciousness• myocardial ischaemia• cardiac arrest.Neurological problems Problems with A, B and/or C may alter thepatient’s neurological status result<strong>in</strong>g <strong>in</strong>:• confusion• agitation• loss <strong>of</strong> consciousness.Sk<strong>in</strong> and mucosal Often the first feature and may be subtle orchangesdramatic:• erythema (a patchy, or generalised, red rash)• urticaria (also called hives, wheals or welts –usually itchy)• angioedema (caused by swell<strong>in</strong>g <strong>of</strong> mucosaltissue) result<strong>in</strong>g <strong>in</strong>:– swell<strong>in</strong>g <strong>of</strong> eyelids and lips (most common)– pharyngeal and laryngeal oedema (caus<strong>in</strong>gupper airway obstruction).There is a range <strong>of</strong> signs and symptoms, none <strong>of</strong> which areentirely specific for anaphylactic reaction, however, certa<strong>in</strong> comb<strong>in</strong>ations<strong>of</strong> signs make the diagnosis more likely (Box 1). Mostanaphylactic reactions develop suddenly and evolve rapidly follow<strong>in</strong>gexposure to a trigger (allergen). There is a rapid progression<strong>of</strong> symptoms result<strong>in</strong>g <strong>in</strong> life-threaten<strong>in</strong>g compromise <strong>of</strong>airway, breath<strong>in</strong>g and/or circulation (Box 2).Some patients have less severe systemic allergic reactionsthat are characterised by sk<strong>in</strong> or mucosal changes alone (eggeneralised urticaria or angioedema). These reactions arenot described as <strong>anaphylaxis</strong> because life-threaten<strong>in</strong>g featuresare not present. Most patients who have sk<strong>in</strong> changescaused by allergy do not go on to develop an anaphylacticreaction. The differential diagnosis <strong>of</strong> <strong>anaphylaxis</strong> is summarised<strong>in</strong> Box 3.Implications for implementationThe implications for implementation <strong>of</strong> these guidel<strong>in</strong>esare primarily those <strong>of</strong> staff education and awareness. Allcl<strong>in</strong>ical staff with<strong>in</strong> the hospital sett<strong>in</strong>g should be able tocall for help and <strong>in</strong>itiate <strong>treatment</strong> <strong>in</strong> a patient experienc<strong>in</strong>gan anaphylactic reaction.Resuscitation equipment and drugs to help with the rapidresuscitation <strong>of</strong> a patient with <strong>anaphylaxis</strong> must be immediatelyavailable <strong>in</strong> all cl<strong>in</strong>ical sett<strong>in</strong>gs. No new drugs forthe <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> are needed. Intramuscular<strong>in</strong>jection <strong>of</strong> adrenal<strong>in</strong>e is the <strong>in</strong>itial <strong>treatment</strong> <strong>of</strong> choice.Membership <strong>of</strong> the Guidel<strong>in</strong>e DevelopmentGroupJasmeet Soar, Co-chair Work<strong>in</strong>g Group and Vice Chair,Resuscitation Council (UK); Richard Pumphrey, Co-chairWork<strong>in</strong>g Group, <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Pathologists; Andrew Cant,<strong>Royal</strong> <strong>College</strong> <strong>of</strong> Paediatrics and Child Health; Sue Clarke,Anaphylaxis Campaign; Allison Corbett, British NationalFormulary; Peter Dawson, <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Radiologists; PamelaEwan, British Society for Allergy and Cl<strong>in</strong>ical Immunology;Bernard Foëx, <strong>College</strong> <strong>of</strong> <strong>Emergency</strong> Medic<strong>in</strong>e; David Gabbott,Executive Committee Member Resuscitation Council (UK); MattGriffiths, <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Nurs<strong>in</strong>g; Judith Hall, <strong>Royal</strong> <strong>College</strong> <strong>of</strong>Anaesthetists; Nigel Harper, Association <strong>of</strong> Anaesthetists <strong>of</strong> GreatBrita<strong>in</strong> and Ireland; Fiona Jewkes, <strong>Royal</strong> <strong>College</strong> <strong>of</strong> GeneralPractioners, Jo<strong>in</strong>t <strong>Royal</strong> <strong>College</strong> Ambulance Liason Committee;Box 3. Differential diagnosis <strong>of</strong> <strong>anaphylaxis</strong>.Life-threaten<strong>in</strong>g conditions:• asthma (can present with similar symptoms and signs to<strong>anaphylaxis</strong>, particularly <strong>in</strong> children)• septic shock (hypotension with petechial/purpuric rash).Non-life-threaten<strong>in</strong>g conditions:• vasovagal episode• panic attack• breath hold<strong>in</strong>g episode <strong>in</strong> a child• idiopathic (non-allergic) urticaria or angioedema.Seek help early if there are any doubts about thediagnosis.2 Cl<strong>in</strong>ical Medic<strong>in</strong>e Vol 9 No 2 April 2009© <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Physicians, 2009. All rights reserved.
<strong>Emergency</strong> <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> <strong>in</strong> <strong>adults</strong>: concise guidanceSummary <strong>of</strong> the guidel<strong>in</strong>esRecommendationGradeATreatment <strong>of</strong> an anaphylactic reaction1 The diagnosis <strong>of</strong> <strong>anaphylaxis</strong> is not always obvious. Cl<strong>in</strong>icians must: C• use the systematic ABCDE (airway, breath<strong>in</strong>g, circulation, disability, exposure) approach to assess andtreat the patienttreat life-threaten<strong>in</strong>g problems as they are found• monitor the patient with a m<strong>in</strong>imum <strong>of</strong> pulse oximetry, non-<strong>in</strong>vasive blood pressure and a 3-leadelectrocardiogram as soon as possible.2 Patients hav<strong>in</strong>g an anaphylactic reaction should expect the follow<strong>in</strong>g as a m<strong>in</strong>imum: Crecognition that they are seriously unwellan early call for help<strong>in</strong>itial assessment and <strong>treatment</strong> based on the ABCDE approachadrenal<strong>in</strong>e therapy, if <strong>in</strong>dicated• <strong>in</strong>vestigation and follow up by an allergy specialist.3 Cl<strong>in</strong>icians manag<strong>in</strong>g an acute anaphylactic reaction should follow the key steps outl<strong>in</strong>ed <strong>in</strong> Figure 1. C4 Adrenal<strong>in</strong>e is the most important drug for the <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> and should be given to all patients Cwith life-threaten<strong>in</strong>g features:• adm<strong>in</strong>ister 0.5 ml <strong>of</strong> 1:1,000 adrenal<strong>in</strong>e (0.5 mg) via the <strong>in</strong>tramuscular (IM) route <strong>in</strong>to the anterolateralaspect <strong>of</strong> the middle third <strong>of</strong> the thighuse a needle long enough to ensure that adrenal<strong>in</strong>e is <strong>in</strong>jected <strong>in</strong>to musclemonitor the patient as soon as possible to assess response to adrenal<strong>in</strong>e• repeat the IM adrenal<strong>in</strong>e dose at 5-m<strong>in</strong>ute <strong>in</strong>tervals if there is no improvement <strong>in</strong> the patient’s condition.Intravenous (iv) adrenal<strong>in</strong>e must only be given by cl<strong>in</strong>icians experienced <strong>in</strong> its use eg anaesthetists, <strong>in</strong>tensivecare and emergency physicians.The use <strong>of</strong> subcutaneous or <strong>in</strong>haled adrenal<strong>in</strong>e is not recommended.5 All patients should be placed <strong>in</strong> a comfortable position: Cpatients with airway and breath<strong>in</strong>g problems may prefer to sit up• ly<strong>in</strong>g flat (with leg elevation) is helpful for patients with hypotension:– do not make patients sit or stand up if they feel fa<strong>in</strong>t as this can cause cardiac arrest• place unconscious patients who are breath<strong>in</strong>g <strong>in</strong> the recovery position.6 All patients with <strong>anaphylaxis</strong> should receive supportive care <strong>in</strong> addition to def<strong>in</strong>itive <strong>treatment</strong> with Cadrenal<strong>in</strong>e. This <strong>in</strong>cludes:• oxygen:– give high flow oxygen immediately at the highest concentration possible us<strong>in</strong>g a mask with an oxygenreservoir• fluids:– adm<strong>in</strong>ister a rapid iv fluid challenge <strong>of</strong> 500–1,000 ml <strong>of</strong> crystalloid or colloid as soon as possible– avoid colloid if it is thought to be cause <strong>of</strong> reaction– monitor the patient’s response and give further doses if necessary• antihistam<strong>in</strong>es:– adm<strong>in</strong>ister 10 mg <strong>of</strong> chlorphenam<strong>in</strong>e IM or by slow iv <strong>in</strong>jection follow<strong>in</strong>g <strong>in</strong>itial resuscitation <strong>of</strong> the patient• corticosteroids:– adm<strong>in</strong>ister 200 mg <strong>of</strong> hydrocortisone IM or by slow iv <strong>in</strong>jection follow<strong>in</strong>g <strong>in</strong>itial resuscitation <strong>of</strong> the patient•other medications:– if patient has symptoms <strong>of</strong> asthma, bronchodilator therapy with salbutamol, ipratropium and/oram<strong>in</strong>ophyll<strong>in</strong>e may be helpful.7 If the trigger for the patient’s anaphylactic reaction is identified, it should be removed if possible. CStop any drug suspected <strong>of</strong> caus<strong>in</strong>g an anaphylactic reaction immediately.• Do not delay def<strong>in</strong>itive <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> if remov<strong>in</strong>g the trigger is not feasible.• After food-<strong>in</strong>duced <strong>anaphylaxis</strong>, attempts to make the patient vomit are not recommended.cont<strong>in</strong>uedCl<strong>in</strong>ical Medic<strong>in</strong>e Vol 9 No 2 April 2009 3© <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Physicians, 2009. All rights reserved.
Jasmeet SoarSummary <strong>of</strong> the guidel<strong>in</strong>es – cont<strong>in</strong>uedRecommendationGradeATreatment <strong>of</strong> an anaphylactic reaction – cont<strong>in</strong>ued8 If cardiorespiratory arrest occurs follow<strong>in</strong>g an anaphylactic reaction: C• start cardiopulmonary resuscitation immediately and call the cardiac arrest team• commence advanced life support (ALS) as soon as equipment is available• use the iv doses <strong>of</strong> adrenal<strong>in</strong>e recommended <strong>in</strong> the ALS guidel<strong>in</strong>es.9 Patients with suspected <strong>anaphylaxis</strong> should be observed <strong>in</strong> hospital for at least six hours and reviewed Cby a senior cl<strong>in</strong>ician:B•patients with the follow<strong>in</strong>g may need careful observation for up to 24 hours:– an asthmatic component to their anaphylactic reaction– previous history <strong>of</strong> biphasic reactions– possibility <strong>of</strong> cont<strong>in</strong>u<strong>in</strong>g absorption <strong>of</strong> allergen– poor access to emergency care– presentation <strong>in</strong> the even<strong>in</strong>g or at night– severe reactions with slow onset caused by idiopathic <strong>anaphylaxis</strong>.Investigation, discharge and follow up <strong>of</strong> patients with <strong>anaphylaxis</strong>1 Mast cell tryptase should be measured to confirm the diagnosis <strong>of</strong> <strong>anaphylaxis</strong>: C• ideally, three time samples should be taken (use a serum or clotted blood sample. Plasma samples canalso be tested):– first sample: as soon as feasible after resuscitation has started– second sample: one to two hours after the start <strong>of</strong> the patient’s symptoms– third sample: after 24 hours or <strong>in</strong> a follow-up allergy cl<strong>in</strong>ic• the m<strong>in</strong>imum requirement is one sample taken one to two hours after the start <strong>of</strong> the symptoms.Mast cell tryptase is not useful <strong>in</strong> the <strong>in</strong>itial recognition and <strong>treatment</strong> <strong>of</strong> <strong>anaphylaxis</strong> and should not delayresuscitation <strong>of</strong> the patient.2 Before discharge from hospital, all patients must be: C• reviewed by a senior cl<strong>in</strong>ician• given clear <strong>in</strong>structions to return to hospital if symptoms return• considered for <strong>treatment</strong> with antihistam<strong>in</strong>es and oral steroids for three days to decrease the chance <strong>of</strong>a further reaction• considered for an adrenal<strong>in</strong>e auto-<strong>in</strong>jector or given a replacement• given a plan for follow up, <strong>in</strong>clud<strong>in</strong>g contact with their general practitioner.3 All patients present<strong>in</strong>g with <strong>anaphylaxis</strong> should be referred to a specialist allergy cl<strong>in</strong>ic to: C• identify the cause <strong>of</strong> the reaction• reduce the risk <strong>of</strong> future anaphylactic reactions• prepare the patient to manage future episodes themselves.Cl<strong>in</strong>icians should refer to the British Society for Allergy and Cl<strong>in</strong>ical Immunology website for a list <strong>of</strong> specialistallergy cl<strong>in</strong>ics (www.bsaci.org).4 All patients should be given <strong>in</strong>formation on: C• the allergen responsible for their anaphylactic reaction and how to avoid exposure to it• how to recognise the early symptoms <strong>of</strong> <strong>anaphylaxis</strong>• how to use their adrenal<strong>in</strong>e auto-<strong>in</strong>jector (if provided)• the importance <strong>of</strong> seek<strong>in</strong>g urgent medical assistance when experienc<strong>in</strong>g <strong>anaphylaxis</strong> and after us<strong>in</strong>g anadrenal<strong>in</strong>e auto-<strong>in</strong>jector.Individuals close to the patient (eg family, carers) must be adequately <strong>in</strong>formed and given tra<strong>in</strong><strong>in</strong>g <strong>in</strong> us<strong>in</strong>gthe adrenal<strong>in</strong>e auto-<strong>in</strong>jector.4 Cl<strong>in</strong>ical Medic<strong>in</strong>e Vol 9 No 2 April 2009© <strong>Royal</strong> <strong>College</strong> <strong>of</strong> Physicians, 2009. All rights reserved.