Post on 22-Dec-2015
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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
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