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Anaphylaxis & Acute Allergic Reactions in the Emergency Department

Anaphylaxis & Acute Allergic Reactions in the Emergency Department. Theodore J. Gaeta, DO, MPH Sunday Clark, MPH Carlos A. Camargo, Jr., MD, DrPH On behalf of the MARC Investigators. www.emnet-usa.org. Outline. Case Presentation Prevalence and Natural History Pathophysiology

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Anaphylaxis & Acute Allergic Reactions in the Emergency Department

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  1. Anaphylaxis & Acute Allergic Reactions in the Emergency Department Theodore J. Gaeta, DO, MPH Sunday Clark, MPH Carlos A. Camargo, Jr., MD, DrPH On behalf of the MARC Investigators www.emnet-usa.org

  2. Outline • Case Presentation • Prevalence and Natural History • Pathophysiology • ED Diagnosis and Management • Food-related Allergic Reactions • Post-care Plans www.emnet-usa.org

  3. Case Presentation 19 year old female with acute onset dyspnea • Dyspnea, wheezing, vomiting and generalized flushing • “minutes after eating a chocolate chip cookie” • Past medical history: eczema www.emnet-usa.org

  4. Case Presentation (continued) Vital signs • SBP 80/p, P 124, R 40, T 98.8oF (37.1oC) • Airway patent, diminished breath sound at the bases with wheezing in the upper fields • Weak pulses with delayed capillary refill • Diffuse erythematous rash observed and Medic Alert tag indicates peanut allergy www.emnet-usa.org

  5. Anaphylaxis • Multi-system syndrome resulting from mediator release • Acute onset • Varies from mild and self-limited to fatal • IgE and non-IgE mediated www.emnet-usa.org

  6. Anaphylaxis Incidence • 21 per 100,000 person-years (95% confidence interval [CI]: 17 - 25 per 100,000 person-years)1 • 10.5 per 100,000 person-years among children (95% CI: 8.1 – 13.3 per 100,000 person-years)2 1Yocum et al. J Allergy Clin Immunol 1999 2Bohlke et al. J Allergy Clin Immunol 2004 www.emnet-usa.org

  7. Insect sting Food Drug RCM Allergen immuno Tx Latex All causes 3% 1-3% 1% 0.1% 3% 1% 5% of adults of children of adults of cases of patients of adults of adults Estimated prevalence of Generalized Allergic Reaction* *urticaria / angioedema or dyspnea or hypotension

  8. 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 • Fisher. Anesth Intens Care 1986 www.emnet-usa.org

  9. Anaphylaxis - Clinical Manifestations • Cutaneous: Pruritus, urticaria, angioedema, flushing • Gastrointestinal: Nausea, emesis, cramps, diarrhea • Ocular: Pruritus, tearing, redness • Genitourinary: Urinary urgency, uterine cramps www.emnet-usa.org

  10. Anaphylaxis -Temporal Pattern • Uniphasic • Biphasic • Initial allergic reaction • Recurrence of same manifestations up to 8 hours later • Protracted • Up to 32 hours • May not be prevented by glucocorticoids www.emnet-usa.org

  11. Anaphylaxis Mediators • Histamine • H1: smooth muscle contraction ­ vasc permeability • H2: ­ vascular permeability • H1+H2: vasodilatation, pruritus • Leukotrienes • Smooth muscle contraction • ­ vascular permeability and dilatation • Nitric Oxide • Smooth muscle relaxation • ­ vascular permeability and dilatation www.emnet-usa.org

  12. Causes of Anaphylaxis www.emnet-usa.org

  13. Causes of IgE-Mediated Anaphylaxis • Antibiotics and other medications -lactams, tetracyclines, sulfas • Foreign proteins Latex, hymenoptera venoms, heterologous sera, protamine, seminal plasma, chymopapain • Foods Shellfish, peanuts, and tree nuts • Exercise induced www.emnet-usa.org

  14. Causes of Anaphylactoid Mediator Release • Complement activation • Iodinated dye • Aggregated IgG • IgA deficiency • Unknown mechanisms • Aspirin • Opiates • Local anesthetics www.emnet-usa.org

  15. Risk Factors Male Consistent antigen administration Shorter time elapsed since last reaction Asthma Severity of Anaphylaxis www.emnet-usa.org

  16. Anaphylaxis Fatalities Post Mortem Findings • Airway (laryngeal) and tissue (visceral) edema • Pulmonary hyperinflation • Tissue eosinophilia • Elevated serum tryptase • Myocardial injury www.emnet-usa.org

  17. Anaphylaxis Fatalities • Fatalities @ 4% • Increased risk •  blockade, severe hypotension, bradycardia, sustained bronchospasm, poor response to epinephrine • Adrenal insufficiency • Asthma • Coronary artery disease Van der Klauw et al. Clin Exp Allergy 1996 www.emnet-usa.org

  18. Anaphylaxis Fatalities 60 50 40 Percentage 30 20 10 0 0-9 10-19 20-29 30+ Age Bock SA et al. J Allergy Clin Immunol 2001 www.emnet-usa.org

  19. Anaphylaxis Differential Diagnosis • Vasovagal syncope • Systemic mastocytosis • Scombroid (fish) poisoning • Other causes of shock www.emnet-usa.org

  20. Anaphylaxis Diagnosis • Clinical features • Serum tryptase (measurable up to 6 hours) www.emnet-usa.org

  21. Anaphylaxis Treatment • O2 , airway maintenance & IV fluids • Loose tourniquet? (to extremity for bee sting) • Epinephrine • 0.01 ml/kg (1:1000) IM q 10-20 min (max 0.3-0.5 ml) • In shock, 0.5- 5 mcg/min (1:10,000) IV to maintain SBP • H1 + H2 histamine receptor antagonists • Diphenhydramine, 1 mg/kg PO/ IM/ IV (max 75 mg) • Ranitidine • Adult, 4 mg/kg PO (max 300 mg), 50 mg IM/IV q 6 h • Child, 1.5 mg/kg IM/IV (max 50 mg) www.emnet-usa.org

  22. Treatment (continued) • Corticosteroids • 1-2 mg/kg prednisone PO (max 75 mg) • 2 mg/kg methylpredisolone IV (max 250 mg) • Not effective in protracted anaphylaxis • Effective in iodinated dye prophylaxis • Inhaled beta-agonists Albuterol 2.5 mg q 15-20 min • Glucagon (consider if patient is on -blocker) www.emnet-usa.org

  23. Return to case Placed on supplemental O2 and cardiac monitor • IV access and fluid bolus • Albuterol via nebulizer • Epinephrine: 0.3 ml IM • Diphenhydramine: 50 mg IV • Ranitidine: 50 mg IV • Methylpredisolone: 125 mg IV www.emnet-usa.org

  24. Response • Despite multiple doses of epinephrine and albuterol the patient remained in respiratory distress • Impending respiratory failure: Rapid sequence intubation • Transferred to ICU • Further history: The patient’s roommate presents a Medic Alert tag indicating peanut allergy www.emnet-usa.org

  25. Food-Related Allergic Reaction • Epidemiology • Fatal • Peanut • Schools • Exercise www.emnet-usa.org

  26. FatalFood Anaphylaxis • Frequency (USA): ~ 150 deaths / year • Risk: • Underlying asthma • Delayed epinephrine • Symptom denial • Previous severe reaction • History: known allergic food • Key foods: peanut / tree nuts / shellfish • Biphasic reaction • Lack of cutaneous symptoms www.emnet-usa.org

  27. Prevalence of Food Allergy • Perception by public: 20-25% • Confirmed allergy (oral challenge) • Adults: 1-2% • Infants/Children: 6-8% • Dye / preservative allergy (rare) • Specific Allergens • Dependent upon societal eating pattern • Milk (infants): 2.5% • Peanut / tree nuts in general population: 1.1% www.emnet-usa.org

  28. Diagnosis: History / Physical • History: symptoms, timing, reproducibility • Acute reactions vs. chronic disease • Diet details / symptom diary • Specific causal food(s) • “Hidden” ingredient(s) • Physical examination: evaluate disease severity • Identify general mechanism • Allergy vs. intolerance • IgE vs. non-IgE mediated www.emnet-usa.org

  29. Disposition • Most patients with allergic reactions can be discharged • Hospitalize or observe patients with airway angioedema, persistent brochospasm, hypoperfusion, cardiac problems, on -blockers • Observe 4 to 6 hours www.emnet-usa.org

  30. Risk Management for Anaphylaxis • Education • Allergen avoidance • Written emergency action plan • Resources (eg, FAAN website: www.foodallergy.org) • Prescription for self-injectable epinephrine • Referral to an allergy specialist

  31. Anaphylaxis – Operational Definition • Two or more organ systems • skin (e.g., hives) • respiratory (e.g., swelling of the lips, tongue, or throat; trouble breathing or shortness of breath; stridor, wheezing) • cardiovascular (e.g., hypotension, dizziness or fainting, altered mental status) • gastrointestinal (e.g., trouble swallowing, abdominal pain) • Hypotension (SBP <100 mmHg) www.emnet-usa.org

  32. “State of the ED” Objective To describe ED management of food allergy Methods The Multicetner Airway Research Collaboration is a program within the Emergency Medicine Network(www.emnet-usa.org) Clark et al. J Allergy Clin Immunol 2004 www.emnet-usa.org

  33. EMNet Sites (137 US sites) 9/22/04 www.emnet-usa.org

  34. Methods (continued) • 21 North American EDs participated in this study • Chart review of randomly selected patients presenting to the ED over a one year period with physician-diagnosed food allergy • ICD-9 codes • 693.1 (dermatitis due to food) • 995.0 (other anaphylactic shock) • 995.3 (allergy, unspecified) • 995.60 (allergy due to unspecified food) • 995.61-995.69 (allergy due to specified foods) www.emnet-usa.org

  35. Results • 678 patients with physician-identified food allergy were randomly selected for chart review • 57% female, 43% white • Mean age, 29 ± 18 years • 92% had documentation of a specific food item as the cause of the current reaction • Only 41% of patients had documentation of a history of allergic reaction to the specific food that caused the current reaction www.emnet-usa.org

  36. Specific Foods* * More than one option allowed. www.emnet-usa.org

  37. Presentation and ED Course * Inhaled -agonists and inhaled anticholinergics www.emnet-usa.org

  38. Outcomes www.emnet-usa.org

  39. Instructions to Avoid Offending Allergen Overall: 40% (95% CI, 36-43%) Goal = 100% www.emnet-usa.org

  40. Self-injectable Epinephrine at Discharge Goal = 100% Overall: 16% (95% CI, 14-20%) www.emnet-usa.org

  41. Referred to Allergist at Discharge Goal = 100% Overall: 12% (95% CI, 9-15%) www.emnet-usa.org

  42. Summary • Although allergic reactions to food can be life threatening, 18% of patients came to the ED by ambulance and only 3% were admitted • A variety of foods provoked the allergic reaction, with crustaceans and peanuts being the most common triggers • Only 16% of patients received a prescription for self-injectable epinephrine when leaving the ED www.emnet-usa.org

  43. Summary (continued) • Similarly, only 12% were referred to an allergist as part of discharge instructions • At a minimum, there is poor documentation of medications prescribed at ED discharge • Although guidelines suggest specific approaches for the emergency management of food allergy, concordance to these guidelines appears low www.emnet-usa.org

  44. Take Home Keys to successful management • Prompt recognition of the signs and symptoms of anaphylaxis • Early administration of IM epinephrine • Volume resuscitation • Comfort and familiarity with 2nd line therapies www.emnet-usa.org

  45. Take Home (continued) A successful post-care plan must include • Education • Allergen avoidance • Written emergency action plan • Educational resources (eg, www.foodallergy.org) • Prescription for self-injectable epinephrine • Referral to an allergy specialist www.emnet-usa.org

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