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Anaphylaxis & Acute Allergic Reactions in the Emergency Department

Learn about anaphylaxis, its manifestations, causes, diagnosis, and treatment in the emergency department with case presentations and vital signs. Understand the prevalence, risk factors, and fatalities associated with acute allergic reactions.

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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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