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Anaphylaxis SHO presentation Tom Francis ICU Registrar Slide 2 Anaphylaxis What is it Pathophysiology Common causes / precipitants Features / signs Treatment After-care / discharge Slide 3 Anaphylactic shock Type 1 IgE mediated (usually) hypersensitivity reaction Chain Reaction Release of histamine and other cytokines from mast cells and basophills Causes contraction of bronchial smooth muscles, vasodilation of peripheral vasculature, capillary leak and cardiac muscle depression Slide 4 ADRENALINE Mainstay of treatment is Adrenaline 0.5mg IM ADRENALINE Slide 5 Precipitants / causes Drugs Abx, cross reactivity B-lactams Muscle relaxants IV contrast Food Bee stings / wasp / horse fly Slide 6 IM injection DELTOID UPPER OUTER THIGH Slide 7 Recognition Airway Airway oedema larynx, lips, tongue, eyelids Stridor is a sign of airway obstruction Breathing Bronchial smooth muscle constriction wheeze, respiratory distress, increased work of breathing Circulation Relaxation of vascular smooth muscle Vasodilation, hypotension and erythema Increased capillary permeability leading to loss of fluid from circulation : hypotension, tissue swelling, urticaria and Angioedema Slide 8 Urticaria Slide 9 Angioedema Slide 10 ADRENALINE 0.5mg IM Half of 1/1000 vial (the small one) Found in emergency box on all wards Can repeat every 5 mins 0.5mg ADRENALINE IM Slide 11 Slide 12 Adrenaline 1 peripheral vasoconstriction via smooth muscle constriction Increased SVR 1 Increased Cadiac output through +ve chrnontropy and inotropy 2 Bronchial smooth muscle relaxation Also acts directly on mast cells preventing further histamine release Slide 13 Slide 14 Promethazine (Phenergan) 25mg slow IV injection (can use IM) Sedating anti-histamine (H1) Prevents capillary leak and helps treat hypotension due to loss of intravascular fluid If persistant hypotension despite treatment with adrenaline can use ranitidine (H2) as second line. 50mg Ranitidine IV slowly Slide 15 Hydrocortisone 200mg IV hydrocortisone Requires reconstituion with sterile water OF NO VALUE IN IMMEDIATE RESUSCITATION Is of value to prevent rebound anaphylaxis though onset of several hours, should be given to prevent further deterioration in severely affected patients Slide 16 IV Fluids Vasodilation and increased vascular permeability 3 rd spacing of fluid into interstitial space DISTRIBUTIVE SHOCK 1 litre Crystalloid or colloid STAT once Adrenaline given IM 1 3 litres commonly required 50mg Ranitidine can help persitant low BP Slide 17 Treatment ADRENALINE 0.5mg IM Airway (and supplemental Oxygen) nebulised adrenaline 5mg (5 x 1/1000) Consider intubation. Breathing bronchospasm usually responds to adrenaline, can give nebulised salbutamol 5mg if wheeze persists. Treat as acute asthma Circulation Raise legs / head down on bed if hypotension Large bore IV access 1 litre IVI stat 50mg Ranitine IV if persistant Slide 18 Slide 19 Treatment Mainstay of treatment is Adrenaline 0.5mg IM ADRENALINE Slide 20 Slide 21 Slide 22 Where now? Pts who require treatment for anaphylaxis need to be discussed with ICU Rebound Anaphylaxis is a concern Tryptase levels to confirm diagnosis