Anaphylaxis
(Redirected from Anaphylactic shock)
This page is for adult patients. For pediatric patients, see:Anaphylaxis (peds).
Background
- Type I hypersensitivity reaction that is either severe in nature or having two or more organ systems involved.
- Clinically Anaphylaxis and its treatment is virtually identical whether it is the traditional IgE dependent anaphylaxis reaction (vast majority), or the IgE independent anaphylactoid reaction
- Precipitants
- Food (most common)
- Medications
- Insect stings
- Latex
- Aerobic exercise
- Idiopathic (rare)
Clinical Features
- Cutaneous symptoms (90%)
- Hives
- Angioedema
- Itching
- Morbilliform rash
- Respiratory symptoms (70%)
- Wheezing
- Shortness of breath
- Throat itching or tightness
- Hoarseness
- Stridor
- Hypoxia, cyanosis
- Gastrointestinal symptoms (40%)
- Abdominal pain
- Nausea, vomiting
- Diarrhea
- Cardiovascular symptoms (35%)
- Hypotension
- Chest pain
- Palpitations
- Central Nervous System
- Uneasiness
- Altered mental status
- Headache, dizziness, confusion
- Syncope
Expected Course
Uniphasic (80-90%)
- Symptoms peak within 30 minutes to 1 hour after onset, resolve within 30 minutes to 1 hour of receiving treatment[1]
Biphasic (10-20%)
Biphasic reactions are rare and can occur anywhere from 10 minutes up to six days after an initial reaction.[2]
- Uniphasic response, followed by asymptomatic period of hour or more, then return of symptoms
- The second phase does not necessarily resemble the first!
- More likely with a severe initial presentation or repeated epinephrine doses. Additionally hypotension, widened pulse pressure, unknown trigger, and drug trigger in children[3][4]
- Little evidence to support the use of discharge steroids to prevent a biphasic reaction
- 0.4% of patients with anaphylaxis had a rebound event while in the ED[5]
Differential Diagnosis
Acute allergic reaction
- Allergic reaction/urticaria
- Anaphylaxis
- Angioedema
- Anxiety attack
- Asthma exacerbation
- Carcinoid syndrome
- Cold urticaria
- Contrast induced allergic reaction
- Scombroid
- Shock
- Transfusion reaction
Shock
- Cardiogenic
- Acute valvular Regurgitation/VSD
- CHF
- Dysrhythmia
- ACS
- Myocardial Contusion
- Myocarditis
- Drug toxicity (e.g. beta blocker, CCB, or bupropion OD)
- Obstructive
- Distributive
- Hypovolemic
- Severe dehydration
- Hemorrhagic shock (traumatic and non-traumatic)
Erythematous rash
- Positive Nikolsky’s sign
- Febrile
- Staphylococcal scalded skin syndrome (children)
- Toxic epidermal necrolysis/SJS (adults)
- Afebrile
- Febrile
- Negative Nikolsky’s sign
- Febrile
- Afebrile
Evaluation
Anaphylaxis is highly likely when ANY ONE of the following criteria is fulfilled[6][7]
Criterion 1 (90% of patients)
- Acute onset of an illness involving the skin, mucosal tissue, or both AND at least one of the following:
Criterion 2 (10-20% of patients)
- TWO OR MORE of the following that occur rapidly after exposure to a LIKELY allergen for that patient
- Involvement of the skin-mucosal tissue (hives, swollen lips-tongue-uvula)
- Respiratory compromise
- Hypotension or associated symptoms
- Persistent gastrointestinal symptoms: (vomiting, diarrhea, crampy abdominal pain)
Criterion 3
- Hypotension after exposure to a KNOWN allergy for that patient (minutes to hours):
- Adults: systolic blood pressure (SBP) <90 mmHg or >30% reduction from baseline
- Pediatrics
- 1 month - 1 year: SBP <70 mmHg
- 1 year - 10 years: SBP <(70 mmHg + [2 x age])
- 11 years - 17 years: SBP <90 mmHg
Management
- Epinephrine
- 1:1000 IM 0.3 - 0.5mg (0.3 - 0.5mL) every 5 - 15 minutes[8][9]
- Give as soon as possible
- Always IM initially [10]
- If response to IM is inadequate: give epinephrine infusion 1:10,000 2 - 10 µg/min
- How to make a quick epinephrine drip: Take your code-cart epinephrine (it does not matter if it is 1:1,000 or 1:10,000) and inject 1mg into a liter bag of NS. Final concentration is 1mcg/ml. Run at 1cc/min and titrate to effect.
- Pediatric: Epinephrine 1:1000 0.01mg/kg (max 0.5mg) IM every 5 to 15 minutes
- IV infusion: 0.05 - 1 mcg/kg/min
- Supplemental oxygen
- Consider endotracheal intubation if airway edema present
- Normal saline bolus
- If unresponsive to epinephrine assume distributive shock and give 1 - 2 liters of normal saline
- Also consider
- Albuterol for bronchospasm resistant to IM epinephrine
- Antihistamines (for symptom control AFTER hemodynamically stable)
- Diphenhydramine: 25 to 50mg IV (1mg/kg in children)
- Ranitidine: 50mg IV (0.5mg/kg in children) (has been found to improve urticaria but not angioedema at 2 hours[11])
- AVOID promethazine as this can worsen hypotension
- Glucocorticoid
- MAY blunt biphasic reaction although little evidence to support usage[12]
- Methylprednisolone: 125mg IV (2mg/kg in children)
- Dexamethasone: 10mg IV or PO (0.6mg/kg in children)
- Glucagon
- 1 - 5mg IV over 5 minutes followed by infusion of 5 - 15 µg/min[13]
- If taking beta-blocker AND unresponsive to epinephrine
- Consider adding additional pressor support if persistent hypotension present
- For example: vasopressin 2-8 units for persistent refractory shock (case series only)[14][15]
- Norepinephrine 0.05 to 0.5 mcg/kg per minute
Disposition
Admit
- Severe and moderate presentations, especially if symptoms did not respond promptly to epinephrine or required repeat dosing
- Labs that may be requested by allergist/admitting team if uncertain diagnosis
- Histamine level - serum elevation 30-60 min following anaphylaxis, window easily missed
- Tryptase - peaks at 2-4 hrs, remains elevated 6-12 hrs
Discharge
- Consider discharge after 1 hour observation, if no severe symptoms and no repeat epinephrine doses (AAAAI recommendations)[4]
- NPV of 1-hour observation was 95%, with NPV for biphasic anaphylaxis after >6 hours of observation of 97.3% [16]
- Send home with an epinephrine autoinjector! (Epi-Pen)
- Up to 6% of the people with anaphylaxis have a repeat ED visit for anaphylaxis within 7 days[5]
See Also
External Links
References
- ↑ Ewan PW. ABC of allergies – Anaphylaxis, BMJ 1998; 316: 1442-1445
- ↑ Milne K. Biphasic Allergic Reactions: Observation, Treatment Guidelines http://www.acepnow.com/article/biphasic-allergic-reactions-observation-treatment-guidelines/
- ↑ Ellis AK, Day JH: Incidence and characteristics of biphasic anaphylaxis: A prospective evaluation of 103 patients. Ann Allergy Asthma Immunology. 2007; 98:64-69
- ↑ 4.0 4.1 Shaker MS, Wallace DV, Golden DBK, et al. Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis. J Allergy Clin Immunol 2020; 145:1082. https://www.aaaai.org/Aaaai/media/Media-Library-PDFs/Professional%20Education/Podcasts/Anaphylaxis-2020-grade-document.pdf
- ↑ 5.0 5.1 Grunau BE et al. Incidence of Clinically Important Biphasic Reactions in Emergency Department Patients With Allergic Reactions or Anaphylaxis. Ann Emerg Med. 2013 Nov 13
- ↑ Brown SGA, Mullins RJ and Gold MS. Anaphylaxis: diagnosis and management, MJA 2006; 185: 283–289
- ↑ Lieberman P et al. The diagnosis and management of anaphyalxis: An updated practice parameter, J Allergy Clin Immunol 2005;115;3:S483-S523
- ↑ Dhami S. et al. Management of anaphylaxis: a systematic review. Allergy. 69 (2014) 168–175. http://onlinelibrary.wiley.com/store/10.1111/all.12318/asset/all12318.pdf?v=1&t=hrspdbpk&s=8067bfd5903c7ffebf4a274f062a71633ebe0507
- ↑ Sheikh A, Shehata YA, Brown SGA, Simons FER. Adrenaline (epinephrine) for the treatment of anaphylaxis with and without shock. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD006312. DOI:10.1002/14651858.CD006312.pub2
- ↑ Simons FER, Gu X, Simons KJ. Epinephrineabsorption in adults: Intramuscular versus subcutaneous injection, J Allergy Clin Immunol 2001;108:871-3
- ↑ Lin, RY et al. Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.
- ↑ Choo KJ, Simons E, Sheikh A: Glucocorticoids for the treatment of anaphylaxis: Cochrane systematic review. Allergy 2010; 65:1205-1211.
- ↑ Campbell RL, et al. Emergency department diagnosis and treatment of anaphylaxis: a practice parameter. Ann Allergy Asthma Immunol. 2014; 113:599e608.
- ↑ Schummer et al. The Pivotal Role of Vasopressin in Refractory Anaphylactic Shock. Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 620-624.
- ↑ Dünser et al. Treatment of Anaphylactic Shock: Where Is the Evidence? Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 359-361
- ↑ Shaker M, Wallace D, Golden DBK, Oppenheimer J, Greenhawt M. Simulation of health and economic benefits of extended observation of resolved anaphylaxis. JAMA Netw Open 2019;2:e1913951.