1. Hypersensitivity

2. Anaphylaxis Nafiseh Kiamanesh

3. Learning Objectives Knowledge of the mechanism which causes anaphylaxis and the agents which are most likely to cause it; be able to recognize the signs and symptoms of anaphylaxis; Understand how to treat anaphylaxis

4. Lecture Objectives Definition Introduction Epidemiology Pathophysiology Aetiology Diagnosis Treatment Prevention

5. What is anaphylaxis? Ana (without); phylaxis (protection / guard) An acute systemic allergic reaction Life-threatening The result of a re-exposure to an antigen that elicits an IgE mediated response Usually caused by a common environmental protein that is not intrinsically harmful Often caused by medications, foods, and insect stings It is a Type I hypersensitivity True vs. pseudo anaphylaxis

6. 4 Types of Hypersensitivity Type I : Mediated by IgE Type II : Mediated by anti-tissue Ab IgG and IgM Type III : Mediated by immune complexes Type IV : Cell-mediated immune complexes

7. History Richet & Portier

8. Epidemiology Underreported 50/100 000 p/yr No known geographic, racial, or sex predilection 1-15% at risk every year 1500 deaths p/yr Global increasing rates

9. Pathophysiology

11. Pseudoanaphylaxis Anaphylactoid Reactions are caused by activation of mast cells and release of the same mediators, but without the involvement of IgE antibodies. Management is similar to anaphylaxis.

12. Primary Symptoms Time to onset is variable, but symptoms usually occur within seconds to minutes of exposure to the offending antigen. CUTANEOUS Swelling (angio-oedema( Urticaria Redness (erythema) Itching (pruritus) RESPIRATORY Wheezing Dyspnoea Rhinitis Laryngeal obstruction causing stridor Hypoxia

13. Secondary Symptoms GASTROINTESTINAL Nausea Diarrhoea Abdominal Pain Vomiting CENTRAL NERVOUS SYSTEM Confusion Feeling of impending doom Apprehension Metallic Taste Altered levels of consciousness CARIOVASCULAR Hypotension Tachycardia Arrhythmias

15. Death Death is usually attributable to asphyxiation from upper airway edema and congestion, irreversible shock, or a combination of these factors. Death may occur after many hours of shock from the effects of the failure of other organs. ANAPHYLAXIS

16. Causes Anaphylaxis: Foods Peanuts Tree nuts Fish and shellfish Soya products Milk Eggs Insect stings Bee venom Wasp venom Chemicals, drugs and other foreign proteins Penicillin and other antibiotics Intravenous anesthetic agents, e.g. suxamethonium, propofol Latex

17. Causes Anaphylactoid: Opiates Aspirin Radio contrast media Physical Exercise Cold Idiopathic: No cause can be identified in 30% of patients with anaphylaxis

18. Note Any protein is a potential allergen, which may cause an anaphylactic reaction

19. Treatment Serum tryptase remains elevated for up to 6 hours Immediate treatment with epinephrine Anti-histamine Others: Corticosteroids β2 agonist (inhaled) Glucagon IV fluids Supplemental oxygen

20. prevention Avoidance of offending antigen, where possible; skin testing and desensitization to materials such as penicillin and Hymenoptera venom, if necessary. Individuals should wear an informational bracelet and have immediate access to an unexpired epinephrine kit.

21. Epi-pen

22. Questions