Anaphylaxis: Exactly what you need to know. Dr. David Carr February 23 rd 2014

Transcription

1 Anaphylaxis: Exactly what you need to know Dr. David Carr February 23 rd 2014

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3 Disclosures I AM NOT AN ALLERGIST OR IMMUNOLOGIST But I treat acute allergic reactions nearly every single shift I also work at the Roger s Centre

4 OBJECTIVES An evidenced based approach to anaphylaxis Highlight the pitfalls and controversies in the management of anaphylactic reactions Lets talk about epinephrine

5 Is this important for you? Onset: Can be rapid yet variable presentations Severity: 80 deaths in Ontario in past 25 years Population: Everyone at risk: 11/80 were peds Treatment: Widely available and effective 18/80 prescribed epinephrine and 9/80 carried

6 Management of anaphylaxis: Barriers to care Establishing a diagnosis of anaphylaxis When and how to use epinephrine Infrequent or delayed epinephrine administration Low rate of epinephrine prescriptions Infrequent or no allergy specialist referrals Conclusion: Lots of room for improvement Canadian Expert consensus recommendations: Wasserman et al Allergy 2010 (65)

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8 Pre Hospital barriers to care 3537 paramedics in the US 98.9% corrected identified classic anaphylaxis 2.9% recognized atypical presentations 46.2% identified epinephrine as the 1 st drug 40% believed benadryl to be first line 38.9% choose IM route 60.5% deltoid vs 11.6% anterior thigh 36.2% felt contraindications to its use in anaphylactic shock Jacobsen RC et al: Prehospital Emerg Care (4)

9 Pearl # 1 Patients with anaphylaxis may present with hypotension alone or without cutaneous or respiratory findings

10 Anaphylaxis: NIAID and FAAN Definition

11 Anaphylaxis: Signs and Symptoms The plus one approach Skin/mucous membranes 80-90% Respiratory 70% GI 45% CV 45% Death is usually 2nd from asphyxiation of upper airway edema or Resp failure> CV collapse

12 Anaphylaxis: management ABC s (fluid/02) Epinephrine Remove the source Steroids H1 Blockers H2 Blockers Glucagon B2 agonists What is the order?

13 Pearl # 2 Epinephrine is the first line drug in anaphylaxis Steroids and antihistamines are second line

14 Pearl # 3 The number one cause of death is not giving epinephrine appropriately in a timely fashion and at the correct dose and route

15 LOCATION LOCATION LOCATION

16 Pearl #4 Epinephrine should be administered into the thigh IM NOT SC

17 Epinephrine dosing If you have to look up the dose, the patient is in trouble IM Dosing: ADULT: mg 1:1000 PEDS: 0.01 mg/kg 1:1000 up to 0.3mg May repeat every 5-15 minutes Delay in epinephrine use à associated with increased risk bi-phasic reaction

18 Epinephrine IV: Keep it simple IV Dosing 1mg of epinephrine (1:10,000) in 1L NS 1 ml/min = 1ug/min

19 Pearl # 5 Epinephrine is safe There are no contraindications to its use in anaphylaxis

20 Treatment: Antihistamines #1 reason patients do not get epinephrine H-1 Blockers well established yet no RCT mg benadryl IV or 1mg/kg in children H-2 Blockers have less evidence Block bradykininà role in angioedema Ranitidine 50 mg iv or 1mg/kg in children ED Study : H-1 + H-2 > H-1 alone Sheikh et al. Cochrane data base review 2007 Lin RY. Ann Emerg Med 2000;36:5:462-8

21 Treatment: Steroids No evidence to support their use Onset of action 4-6 hoursà no immediate role in acute anaphylaxis May have a role in preventing recurrence Solumedrol 125 mg IV Prednisone 50 mg po Dexamethasone 10 mg Choo et al. Cochrane data base review 2012

22 Treatment: Glucagon Reserved for patients on beta blockers who have refractory hypotension despite epinephrine May consider ½ dose epi to avoid unopposed alpha stimulation in patients on BB`s Use limited by nausea and vomiting Glucagon dose: 1-5mg IV followed by infusion

23 Pearl # 6 Anaphylactic reactions are biphasic or rebound 5-20% of the time Up to hrs Average 8hr later

24 Who to observe/admit? Be afraid of Early symptom onset and late treatment initiation Asthmatics Severe anaphylaxisà multiple doses of epinephrine History of severe reactions Socioeconomic and caregiver concerns Patients on BB s or ACEI or other BP drugs 302 ED patients retrospective study Two fold risk of multisystem involvement Increased risk of inpatient admission (OR 4.0) Lee S, et al J Allergy Clin Immunol. Apr 2013;131(4):1103-8

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26 Multicenter chart review of 21 ED s in North America: 678 patients in % received antihistamines 48% received steroids 16% received epinephrine 55% severe acute allergic reactions: ONLY 24% of those received Epi 97% were discharged: 16% with an auto-injector 12% allergist referral Clark et al: J Allergy and Clinical Immunology 2004 : 133(2)

27 Standard practice NOT standard of care Reasonable period of observation: 4-6 hours Epinephrine auto-injector x 2 Steroids x 3 days or dexamethasone Reduce likelihood of biphasic reaction H1 and H2 blockers for 72 hours Allergist referral

28 Summary Epinephrine Early Anterior lateral thigh IM Auto-injector to go Know which drugs are second line Keep sick anaphylactic patients around Refer patients to allergists on discharge

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