ANAPHYLAXISANAPHYLAXIS

Ig-E mediated Ig-E mediated anaphylaxisanaphylaxis

Release of mediators from mast Release of mediators from mast cells and basophils cells and basophils

Histamine Histamine PGD2 PGD2 LTC4LTC4 Tryptase Tryptase leads to the clinical presentation of leads to the clinical presentation of

anaphylaxisanaphylaxis

Stimulation of H1 and H2 Stimulation of H1 and H2 receptorsreceptors

Profound vasodilationProfound vasodilation Decrease in systemic vascular Decrease in systemic vascular

resistance with hypotensionresistance with hypotension TachycardiaTachycardia FlushingFlushing Increase in bronchial and GI Increase in bronchial and GI

smooth muscle contraction and smooth muscle contraction and glandular secretionglandular secretion

TryptaseTryptase

Inactivates fibrinogen to inhibit Inactivates fibrinogen to inhibit coagulation : key feature of coagulation : key feature of anaphylaxisanaphylaxis

decreases the activity decreases the activity NeuropeptideNeuropeptide VIP :bronchoconstrictionVIP :bronchoconstriction

Phathogenic mechanism Phathogenic mechanism and aetiology of and aetiology of anaphylaxisanaphylaxisI . IgE – mediated anaphylaxis ( 60 %)I . IgE – mediated anaphylaxis ( 60 %) Drugs: penicillin cephaosporins, Drugs: penicillin cephaosporins,

sulphonamides, tetracyclines, quinolones sulphonamides, tetracyclines, quinolones Foreigns protein s : horse serum, egg albumin, Foreigns protein s : horse serum, egg albumin,

insect venom, enzym like papain, insect venom, enzym like papain, chemopapain, latexchemopapain, latex

Food ( 30 %) : eggs, milk, wheat, soy, peanut, Food ( 30 %) : eggs, milk, wheat, soy, peanut, tree nut, shellfish, apple, peachtree nut, shellfish, apple, peach

Therapeutic and diagnostic agent : anaesthetic Therapeutic and diagnostic agent : anaesthetic agents, muscle relaxants, hormonesagents, muscle relaxants, hormones

Allergen immunotherapyAllergen immunotherapy Exercise induced anaphylaxisExercise induced anaphylaxis

II. Imune complex- mediated II. Imune complex- mediated anaphylaxisanaphylaxis

Blood and blood productsBlood and blood products Dialysis membranesDialysis membranes

III direct mast cell degranulationIII direct mast cell degranulation Opiates, quinolones, vancomycin, Opiates, quinolones, vancomycin,

muscle relaxantsmuscle relaxants Radio contrast mediaRadio contrast media

IV. Modulators of arachidonic acid IV. Modulators of arachidonic acid metabolismmetabolism

Aspirin, indomethacinAspirin, indomethacin

V. idiopathic anaphylaxisV. idiopathic anaphylaxis ExerciseExercise Catamenial anaphylaxisCatamenial anaphylaxis Idiopathic anaphylaxisIdiopathic anaphylaxis

Diagnosis of Diagnosis of anaphylaxisanaphylaxis

Symptom presentationSymptom presentation

Rapid in onset (usually within Rapid in onset (usually within minutes of exposure to the minutes of exposure to the precipitant) and progress rapidly, precipitant) and progress rapidly, 10 – 20 minutes10 – 20 minutes

The speed of onset and clinical The speed of onset and clinical features vary with allergen features vary with allergen concentration and patient’s concentration and patient’s sensitivitysensitivity

Differential diagnosisDifferential diagnosis

All causes of respiratory obstruction and All causes of respiratory obstruction and vascular collapse including :vascular collapse including :

Pulmonary embolismPulmonary embolism Cardiac arrythmiasCardiac arrythmias Cardiac tamponadeCardiac tamponade Myocardial infarctionMyocardial infarction SepsisSepsis Seizure disordersSeizure disorders Insulin reactionInsulin reaction

Additional testsAdditional tests

Tryptase Tryptase Specific IgE antibodies are Specific IgE antibodies are

raised : SPT, RASTraised : SPT, RAST Provocation tests ---- RAST (-)Provocation tests ---- RAST (-)

Management of Management of anaphylaxisanaphylaxis

Management of the acute episodeManagement of the acute episode Subsequent evaluationSubsequent evaluation ProphylaxisProphylaxis

Management of Management of anaphylaxisanaphylaxis