Transcript anaphylaxis
Anaphylaxis A Life-threatening Emergency 朱士傑 風濕免疫過敏科 Anaphylaxis A serious allergic reaction that is rapid in onset and may cause death Anaphylactoid Reaction IgE-independent Clincially indistingushable from anaphylaxis 不建議使用 Anaphylaxis Incidence increasing (youngest, food) 21 – 49.8 per 100,000 personyears ( person-years) Under diagnosis, under-reporting, a variety of definition Anaphylaxis Is Not Rare Insect sting 3% of adults Food 1-3% of children Drug 1% of adults RCM 0.1% of cases Immuno Tx 3% of patients Latex 1% of adults All causes 5% of adults Mechanisms of Anaphylaxis Type I hypersensitivity reaction Allergen exposure Production of allergen-specific IgE IgE-sensitized mast cells and basophils IgE-mediated degranulation upon reexposure to allergen Mechanisms of Anaphylaxis Complement activation Type II hypersensitivity Type III hypersensitivity Aggregated Ig Direct mast cell activation Drugs (e.g. ASA, vancomycin), exercise, cold, idiopathic IgG-dependent (not proven in human) The activators of mast cells Anaphylaxis Mediators Histamine H1: smooth muscle contraction vascular permeability, vasodilatation H2: vascular permeability H1+H2: vasoilatation, pruritus Leukotrienes Smooth muscle contraction vascular permeability and dilatation Causes of IgE-Mediated Anaphylaxis Antibiotics and other medications Foreign proteins Latex, hymenoptera venoms, heterologous sera, protamine, seminal plasma, chymopapain allergen vaccines, polysaccharide Foods Beta lactams, tetracyclines, sulfas, aspirin, ibuprofen Peanut, tree nuts, shellfish, fish, milk, egg Exercise (possibly, in food- and medicationdependent events) Biologic agent: cetuximab, infliximab, omalizumab Causes of IgE-independent Mediator Release Complement activation-activation of contact system Radiocontrast media protamine (possibly) Dialysis membrane Ethylene oxide gas on dialysis tubing Direct release of mediators from mast cells and basophils Opiods Muscle relaxants Exercise Physical factors (heat, cold) Causes of IgE-independent Mediator Release Disturbance in arachidnoic acid metabolism Aspirin Nonsteroidal antiinflammatory drugs Immune aggregates Gammaglobulin IgG-anti-IgA Possible dextran and albumin Cytotoxic Transfusion reactions to cellular elements (IgG, IgM) Incidence and/or Severity of Anaphylaxis Risk Factor Age Gender Route of administration Constancy of antigen administration Time elapsed since last reaction Atopy Anaphylaxis - Clinical Manifestations Cardiovascular Tachycardia then hypotension Shock: ≧ 50% intravascular volume loss Bradycardia (4%) (transient or persistent) Myocardial ischemia Lower respiratory - bronchoconstriction wheeze, cough, shortness of breath Upper respiratory Laryngeal/pharyngeal edema Rhinitis symptoms Anaphylaxis - Clinical Manifestations Cutaneous Pruritus, urticaria, angioedema, flushing Gastrointestinal Nausea, emesis, cramps, diarrhea Ocular Pruritus, tearing, redness Genitourinary Urinary urgency, uterine cramps Case 1 Woman aged 20, six months pregnant Trigger: Chinese meal Symptoms and treatment: one hour after start of meal felt faint; mild asthma; sever dyspnoea and laryngeal oedema; loss of consciousness; taken to emergency department after 10 minutes; on arrival cyanosed, respiratory arrest; periorbital oedema; salbutamol infusion; cardiac arrest four minutes later; adrenaline given; intubated with difficulty and ventilated Recovered Cause: allergy to green pepper Case 2 Woman aged 30 Trigger: one teasponful muesli Symptoms and treatment: immediate itching of mouth; throat swollen and uncomfortable inside; vomited; dyspnea (could not breathe, different from her asthma); laryngeal edema (obstruction in throat); lightheaded; no loss of consciousness; used her own salbutamol inhaler (no effect); taken to emergency department; respiratory distress; intense erythema and generalised urticaria; given intramuscular adrenaline and chlorpheniramine Rapid recovery Cause: allergy to brazil nuts and hazelnuts Case 3 Boy aged 8 months Trigger: Tiny quantity of peanut butter Symptoms: blisters around mouth; distressed; vomiting; dyspnea; urticaria Cause: allergy to peanuts Case 4 Woman aged 26 Trigger: vaginal examinations during labour Symptoms: itching of vulva; oedema of labia; generalised urticaria and pruritus; mild dyspnoea; felt woozy, lightheaded, odd, shaking Cause: allergy to latex rubber Anaphylaxis -Temporal Pattern Uniphasic Biphasic (3%-20%) Same manifestations as at presentation recur up to 8 hours later Protracted Up to 32 hours May not be prevented by glucocorticoids Food-Related Anaphylaxis Frequency: ~ 150 deaths / year The most common single cause of anaphylaxis in ED in USA.(young) Risk: Underlying asthma Delayed epinephrine Symptom denial Previous severe reaction History: known allergic food Key foods: peanut/ nuts / shellfish Biphasic reaction Lack of cutaneous symptoms Schools, no predictive markers Exercise Natural History in Food allergy Dependent on food & immunopathogenesis ~ 85% Cow Milk, egg, wheat, soy allergy remit by 3 yrs Declining/low levels of specific-IgE predictive IgE binding to conformational epitopes predictive Allergy to peanut, nuts, seafood typically persisited Peanut Allergy Factors Associated with development of peanut allergy in childhood family history of peanut allergy occurrence of oozing crusted skin rashes, topical use of peanut-oil based preparation exposure to soy protein Prevention Recombinant anti-IgE antibody Gene (naked DNA) immunization N E Engl J Med, march 13, 2003 Classification of Insect Sting Reactions Normal Immediate, local, transient Large local Delayed, prolonged, progressive Systemic Immediate, generalized Other Toxic, serum sickness Natural History of Insect Sting Allergy Spontaneous loss of clinical venom sensitivity Adults differ from children Most fatal reaction on the first sting reaction Evolution of systemic reactions frequency and severity large local into systemic no predictive markers Insect sting and bites Anaphylaxis Indications for Venom Immunotherapy 98% efficacy Medical criteria history of systemic reaction positive venom skin test Non-medical considerations age of patient alterations in life style co-existing diseases costs Allergen Immunotherapy - Systemic Reactions 10-15% during initial immunotherapy, 1-3% during maintenance Most in < 20 minutes, but severity worse with later onset Systemic reactions not preceded or predicted by large local reactions Not correlated with asthma in all studies Related to: dose/vial errors, unstable asthma, seasonal flare, extreme sensitivity, ß blockers, new vial / new extract, rush schedule Fatal reactions: 58 observed over 25 years: 90% in < 30 minutes 50% delayed use of epinephrine 25% prior systemic reactions – 30% due to errors – 50% with acute asthma – 25% peak pollen season Anaphylaxis Exercise-Induced Syndrome Prodrome - flushing, pruritus, fatigue Early - urticaria, angioedema Established - stridor, GI symptoms, collapse Late - headache Precipitating Events: isometric and isotonic exercise; hot environment, foods, medications Temporally unpredictable Anaphylaxis Exercise-Induced Syndrome Treatment / Prevention Avoidance of exercise, especially in heat Avoidance of allergenic foods before exercise Buddy system-epinephrine Latex Allergy Risk Groups for Latex Allergy Patients with history of multiple surgeries Health care workers Other occupational exposure Rubber product workers, hair dressers, house cleaners Individuals with atopy Meningomyelocele or severe urologic anomalies Hay fever, rhinitis, asthma, or eczema Patients with specific food allergies Banana, kiwi, avocado, chestnut, etc. Similar proteins Latex Allergy Most important step is avoidance of exposure in susceptible patients With universal precautions, the problem will likely worsen Hospitals should strive for low allergen environments Powderless gloves with low extractable protein content Protect yourself Treat dermatitis Cover hand wounds with tegaderm Anaphylactoid reaction to RCM IV, hysterosalpingogram, myelogram, retrograde pyelogram Frequence:5-8 %, 0.1% for life-threating reaction 16% to 44% for repeated reaction Pretreatment and use of lower osomolar RCM, the risk is reduced to 1% Drug Hypersensitivity Prevention Ascertain host risks Avoid cross-reactive drugs Use of predictive skin tests Prudent use of drugs Preferential use of oral drugs Anaphylaxis Fatalities Fatalities ≈ 4% Increased Risk beta blockade, ACE inhibitors, severe hypotension, bradycardia, sustained bronchospasm, poor response to epinephrine Adrenal Insufficiency Asthma Coronary Artery Disease Anaphylaxis Fatalities Post Mortem Findings Airway (laryngeal) and tissue (visceral) edema Pulmonary hyperinflation Tissue eosinophilia Elevated serum tryptase Myocardial injury Anaphylaxis Diagnosis Clinical Features Histamine Serum Tryptase measurable up to 6 hours Prevention of Anaphylaxis History: drug, venom, food, latex reactions Avoidance, Medic-Alert and ID card Penicillin skin tests & desensitization Administer drugs orally rather than parenterally when possible Hymenoptera avoidance & immunotherapy Iodinated Dye Pretreatment Avoid ß blockade in those on immunotherapy or at risk of Hymenoptera anaphylaxis Immunotherapy in those on ß blockers ACE inhibitors in food / Hymenoptera anaphylaxis Management ABC’s, early airway intervention as needed Early administration of epinephrine 0.01 mg/kg - 0.3 - 0.5mg, IM. Maximum dose, 0.5 mg. IV – 5-10 μg (0.2 μg/kg) for hypotension) 0.1- 0.5 mg in cardiovascular collapse Remove allergen (stingers), or apply tourniquet if exposure site on extremity 2 large bore IV lines : Volume resuscitate with crystalloid or colloid solutions Management continued Glucagon 1 -5 mg IV (if epinephrine contraindicated or ineffective) (activate adenylate cyclase) Anti-histamines: Benadryl 50 mg iv Pepcid 20 mg iv; Ranitidine 50 mg iv Corticosteroids (Hydrocortisone, prednisone, Methylprednisolone) Vasopressors: dopamine,levarterenol, vasopressin Ongoing evaluation of airway / vital signs Anaphylaxis Treatment Corticosteroids Not effective in protracted anaphylaxis Effective in iodinated dye prophylaxis The efficacy in anaphylaxis not established Prolonged resuscitation Risk Management for Anaphylaxis Ask the questions Prescribe epinephrine injector Refer to allergy specialist EpiPen® auto-injector 藥物使用注意事項 謹慎評估藥物使用之利弊得失。 可以使用口服藥品時避免注射。 注意衛生署核准仿單之適應症、禁忌及相關公告。 Off-label use時，應明確告知病人及家屬。 注射前應詳細查詢病人對藥物有無過敏病史 注射藥品後，建議觀察病人至少30分鐘。 需備妥急救相關設備及藥品 (需留意藥品之保存期限)。 發生嚴重過敏性反應時，應注意epinephrine之使用時機。 急救過程必須詳實紀錄於病歷中。 問 題 ?