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This is a Test It is ONLY a Test. A 16 y/o girl just passed out after receiving her penicillin shot for strep throat (“doesn’t swallow pills”). Which of the following will be most useful to know in treating her: A Her Blood Pressure B Her Glucose level C Her Heart Rate
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This is a Test It is ONLY a Test
A 16 y/o girl just passed out after receiving her penicillin shot for strep throat (“doesn’t swallow pills”). Which of the following will be most useful to know in treating her: A Her Blood Pressure B Her Glucose level C Her Heart Rate D Your Heart Rate
Which of the following is the safest and most efficient route to administer epinephrine in an allergy emergency: A IV B Sub Q C IM D PR
Which of the following potential allergens do not generally cross-react: A. COX-2 inhibitors & Ibuprofen B. Filberts & Pecans C. Peanuts & Tofurky D. Lobster & Shrimp
A first year PEM fellow attending conference developed a sudden onset of urticaria, lip swelling and DIB. The etiology is most likely a reaction to: A smelling someone else’s lunch B a spider bite C another “billing talk” by Dr Linzer
When advising parents/patients on how to administer an “epi-pen” you should tell them to: A. hold it against the triceps and squeeze the trigger B. “stab” it into the anterior thigh C. hold it against the lateral thigh and push
Which is NOT a clinical presentation of anaphylaxis: A. Vomiting and Diarrhea B. Syncope C. Altered Mental Status D. Itchy Tongue
In counseling a 50kg 15 year old after a severe episode of anaphylaxis to a bee sting your best advice is that if they get stung again they first should take A. (2) 25mg diphenhydramine capsules PO B. (5) tsp diphenhydramine elixer PO C. .5mg epinephrine SQ D. 60mg prednisone PO
Which of the following treatments has been shown to decrease the incidence of biphasic reactions: A. Corticosteroids B. Epinephrine C. Diphenhydramine D. Ranitidine
ANAPHYLAXIS Michael Greenwald, MD Pediatric Emergency Medicine Emory University Children’s Healthcare of Atlanta @ Egleston
Objectives • Recognize patients with, or at risk for, anaphylactic reaction • Understand the immunologic basis for anaphylactic reactions • Know the interventions appropriate for anaphylactic reactions • Know the appropriate medical follow-up
Historical Background • ana- backwardphylaxis- protection • Portier and Richet: reactions in dogs exposed to sea anenome toxin • First documented case: Egyptian pharoah 2640 B.C. dies after wasp sting
Defining Anaphylaxis • Acute • Systemic • Allergic (i.e. requires prior exposure)
Special Features of Anaphylaxis • Spectrum of severity • Variety of manifestations • Uniphasic, biphasic or protracted
Top triggers: then penicillin insect venom food Top triggers: now Latex (27%) Food (25%) Drugs (16%) Venoms (15%) Epidemiology
Anaphylaxis Epidemiology • 84,000 cases/year in US • 1% fatal • Kids > adults • Food Allergy • under 4 y/o: 6-8% • After 10 y/o: 2% • 29,000 cases food induced anaphylaxis/year • 2000 hospitalizations • 150 deaths; high association with asthma, peanut/tree nut allergy • Peanuts are # 1 and increasing in Western nations
Hypersensitivity review: Gell and Coombs Classification Type I - Anaphylactic Type II - Cytotoxic Type III - Immune Complex Type IV - Delayed Type
Type I - Anaphylactic • Immediate: Exposure to reaction < 30minutes • Late Phase: Exposure to reaction: 2-12 hours • Exposure to reaction: <30minutes • Effector cell: IgE • Antigen: pollens, foods, drugs, venoms • Mediators: histamine, leukotrienes • Manifestations: anaphylaxis, allergic rhinitis, allergic asthma, urticaria
Type II - Cytotoxic • Exposure to reaction:variable (minutes to hours) • Effector cell:IgG, IgM • Target:Red blood cells, Lung tissue • Mediators:Complement • Examples:Immune hemolytic anemia, Rh hemolytic disease, Goodpasture syndrome
Type III - Immune Complexes • Exposure to reaction:6 - 21 days • Effector cell:Antigen with Antibody • Target:Vascular endothelium • Mediators:Complement, Anaphylatoxin • Symptoms:fever, urticaria, arthralgia, arthritis, lymphadenopathy • Examples:Serum sickness, PSGN
Type IV - Delayed Type • Exposure to reaction:24-48 hours • Effector cell:Lymphocytes • Antigen:Chemicals, Mycobacterium tuberculosis • Mediators:Lymphokines • Examples:Contact dermatitis, Tuberculin skin reactions
Anaphylaxis and Her Cousin • Anaphylaxis • IgE mediated • IgG - immune complex mediated • Anaphylactoid • direct stimulation of mast cells and basophils • unknown mechanism
IgE - mediated Anaphylaxis • Prior exposure required • Allergen-IgE binding induces release of mediators: • histamine • prostaglandins • platelet activating factor • tryptase
IgG -immune complex mediated • complement activated by immune complexes or other agents • Tissue antigens - RBC, WBC, Plts • Serum proteins - Immunoglobulin, cryoprecipitin • anaphylatoxins: C3a, C5a
Anaphylactoid : Direct stimulation • direct stimulation of mast cells and basophils • unknown mechanism - suspect high osmolarity • examples: radiocontrast media (not assoc w/ iodine, shellfish allergy), mannitol, opiates, curare, dextran, chemotherapeutic agents
Unexplained Anaphylaxis • Unknown mechanism: • ASA and other NSAIDS • preservatives • exercise • mastocytosis • cholinergic urticaria with anaphylaxis • progesterone: “catamenial anaphylaxis”
Unexplained Anaphylaxis • Idiopathic anaphylaxis: unknown trigger • up to 37% of all reactions • clinically indistinguishable from other forms • particularly stressful to patients
Epidemiology • Patients at risk: • Does atopic history matter? • Who gets the worst reactions? • Latex
Allergens • Drugs • Foods • Venoms • Latex
Defining Drug Reactions • PredictableDrug Reactions • 80% of all adverse effects • dose dependent • related to known pharmacological effect • Unpredictable Drug reactions • not dose dependent • occurs in susceptible individuals • unrelated to known pharmacological effect
Drugs • Antimicrobials • Penicillin: 2 potential groups of allergens • Major determinant: Benzyl penicilloyl • Minor determinants: penicillin, penicilloate, penilloate, penicilloylamine • Cephalosporins • Sulfonamides
Drugs • NSAIDS • bronchospasm in 2-10% of asthmatics • unknown mechanism: IgE and mast cells not involved
Drugs • Macromolecules: • protamine • insulin • IVIG • 2 recognized mechanisms • IgA deficiency high risk • slow infusion and pretreat
Drugs • Chemotherapeutic agents: L-Asparaginase • Vaccinations: MMR? • Immunotherapy • 17 fatalities reported 1985-1989 (10 million shots given annually) • precautions for medical facility: • observe 20 minute • medications and airway support available
Drugs • Radiocontrast media • mast cell degranulation from anaphlatoxins of complement cascade • older agents: Hypaque, Renigrafin • mild reaction in 5%, severe - 1/1000, death - 1/10-40,000 exposures • risk factors: • atopic/asthma history • adult
Foods • Tree nuts: 1% Americans (3 million) allergic • Legumes: 25-35% also allergic to tree nuts • Shellfish • Fish • Milk • Eggs • Food additives: sulfites
Arachis oil (peanut oil) Baked Goods and mixes Biscuits, cookies, pastries Candy Cereals Chocolate Emulsifiers, flavorings Ethnic foods: African, Chinese, Mexican, Thai, Vietnamese Ice Cream Margarine Milk formula Satay Sauce (thai sauce) Soft drinks Soups Sunflower seeds Vegetable fats and oils Foods That May Contain Peanut Oil
Venoms/Antivenins • 5 major stinging insects in the US: • honeybees • wasps • yellow jackets • hornets • fire ants • Rabies and snake antivenin
Latex • incidence low, except for risk groups: • >1000 episodes and 15 deaths attributed • surgical and dental procedures highest risk • RAST testing available
Exercise-induced • Variety of forms of exercise • not heat alone • not associated with atopy/asthma • strong genetic predisposition • histamine and parasympathetic tone, sympathetic tone
Exercise-induced • 4 phases: • Prodrome: fatigue, warmth, pruritis & erythema • Early: urticaria, angioedema • Fully established: (30’- 4 hours) stridor, choking, N/V/D, syncope, hypotension • Late: fatigue, warmth, headache, lasts up to 72 hours
Exercise-induced • Diagnosis: may resemble asthma or cholinergic urticaria • very unpredictable; some associated with foods • Management: • recognize early signs and rest • avoid hot, humid weather • exercise with a partner
Symptoms • Manifestations in the “shock organs” • skin, respiratory tract, gastrointestinal tract, cardiovascular system • Why there? • rich in mast cells • sensitive to effects of mast cell mediators • exposure to high concentrations of antigen
Skin • Early signs: • Flushing, feeling warm • Erythema • Pruritis • Urticaria • Angioedema • Pallor
Respiratory • Upper airway • Nose & eyes: pruritis and watery discharge, sneezing • Lips & tongue: swelling and pruritis • Larynx & epiglottis: edema with hoarseness, dysphonia to asphyxia • Bronchi: bronchospasm with wheezing, decreased aeration, to apnea, asphyxia
Gastrointestinal • not only with food triggers • crampy abdominal pain, nausea, vomiting, watery diarrhea, gastointestinal bleeding, fecal incontinence
Cardiovascular • Intravascular volume depletion • Direct effects on the heart: • arrythmias • reduced contractility • reduced coronary blood flow • Early: dizziness and confusion • May progress to: syncope, seizures, loss of consciousness shock, cardiac arrest