ANAPHYLAXIS YOGESH NATALY AK ED “ITS TYPICAL EXPLOSIVE ONSET AND UNFORESEEN NATURE OF SEVERITY IS FRIGHTENING” (Bochner B.S, Lichtenstein L.M. Anaphylaxis: Current Concepts. New England Journal of Medicine,1991. 324: 1785-1790)

ANAPHYLAXIS “IMMUNE-MEDIATED LIFE-THREATENING SYNDROME RESULTING FROM THE SUDDEN RELEASE OF MAST CELL AND BASOPHIL-DERIVED MEDIATORS INTO THE CIRCULATION” (Kemp S.F, Lockey R.F. Anaphylaxis: a review of causes and mechanisms.J Allergy Clin Immunol.2002 Sep;110(3):314-8)

ANAPHYLACTOID “CLINICALLY INDISTINGUISHABLE SYNDROME, INVOLVING SIMILAR MEDIATORS BUT NOT MEDIATED BY IgE ANTIBODY AND NOT NECESSARILY REQUIRING PREVIOUS EXPOSURE TO THE INCITING SUBSTANCE” (Bochner B.S, Lichtenstein L.M. Anaphylaxis: Current Concepts. New England Journal of Medicine,1991. 324: 1785-1790)

EPIDERMIOLOGY 1 PER 1,500 PATIENT 154 FATAL CASES PER 1,000,000 HOSPITALISED CASES USA 84,000 ANAPHYLAXIS AND 840 FATALITIES BETA-LACTAM 1 IN 5,000 EXPOSURES WITH 400 TO 600 FATALITIES FOOD 150 FATALITIES FOR 30,000 ANAPHYLACTIC REACTIONS.

COMMON CAUSES FOOD: peanuts, other nuts, fish, shellfish, egg, milk. INSECT VENOM: bee and wasp sting, fire ants, snake. DRUGS: antibiotics, iv anaesthetic drugs, aspirin, nsaids, opioids, haemaccel. LATEX RUBBER. RARELY, exercise, vaccines, heat, cold, sunlight. IDIOPATHIC.

MECHANISM in ANAPHYLAXIS

MECHANISM in ANAPHYLAXIS

MECHANISM in ANAPHYLACTOID REACTION COMPLEMENT FIXATION: release of anaphylatoxins (C3a, C5a) e.g. incompactible transfusions, radioconstrast media. KININ PRODUCTION: ACE inhibitors. DIRECT RELEASE: HISTAMINE RELEASE: opioids, haemaccel ARACHIDONIC METABOLISM: aspirin, nsaids

MEDIATORS A VARIETY OF CHEMOTACTIC, VASOACTIVE AND SPASMOGENIC COMPOUNDS MEDIATE THE ANAPHYLACTIC REACTION. IMMEDIATE (5-30 mins): histamines, leukotrienes Intense reaction characterised by oedema, mucus secretion, and smooth muscle spasm. LATE (2-8 hours): leukotrienes, PAF, TNF-, cytokines Recruit other inflammatory cells and release additional waves of mediators that cause injury

Ewan P.W. Anaphylaxis. BMJ May 1998; 7142: 1442-45 EFFECTS Ewan P.W. Anaphylaxis. BMJ May 1998; 7142: 1442-45

DIFFERENTIAL DIAGNOSIS Facial swelling or oedema Bronchial asthma, pulmonary oedema, chemical irritant exposure, FB airway obstruction and tension pneumothorax Vasovagal reaction CASE PRESENTATION 19 yo F 8 weeks pregnant presenting with hypotension Quick history and examination were diagnostic

LABORATORY TESTING NO SPECIFIC IMMEDIATE DIAGNOSTIC LAB TEST NO REPLACEMENT FOR A BRIEF BUT SUCCINCT HISTORY FBC, GLUCOSE, ELECTROLYTES, LFTs, CXR, ECG, ABG MAST CELL TRYPTASE ASSAY highly sensitive indicator of anaphylaxis serum levels parallel histamine (half-life of mins.) peaks in an hour following the reaction elevated for 4 hours (half-life of 2 hours) used more in postmortem diagnosis of anaphylaxis $149.45 per test

TREATMENT FIRST-LINE SECOND-LINE O xygen Adrenaline (Dose: 0.3-0.5 ml im 1:1000 q5-10min) -adrenergic 1-adrenergic 2-adrenergic cAMP Fluids colloids or crystalloids SECOND-LINE Anti-histamines(H1 and H2) promethazine ranitidine Steroids hydrocortisone Glucagon (in patients on -blockers) Nebulised salbutamol and other bronchodilators

Combined H1 and H2 receptor blocker use TREATMENT Combined H1 and H2 receptor blocker use “Consensus regarding the use of antihistamines in acute anaphylaxis now favours a combination of an H1 and H2 receptor blocker” “Acute urticaria should now be given H1 receptor blocker together with H2 receptor blocker” (Brown AFT 1998 Therapeutic controversies in the management of acute anaphylaxis. Journal of Accident and Emergency Medicine 15: 89-95)

DISCHARGE BIPHASIC ANAPHYLAXIS (5%) DISCHARGE MEDICATION (3days) prednisone 40mg daily ranitidine 150mg Bd loratidine 10mg daily INSTRUCTIONS TO RETURN PROTECT AGAINST FURTHER ATTACKS / EDUCATE REFERAL TO AN ALLERGIST

ESSENTIALS DIAGNOSIS IS ENTIRELY CLINICAL NEVER UNDERESTIMATE THE POTENTIAL FOR DETERIORATION PARENTAL ADRENALINE IS SAFE AND EFFECTIVE 6-8 HOUR OBSERVATION IN PATIENTS RECEIVING ADRENALINE CAREFUL DISCHARGE PLANNING