Anaphylaxis & Acute Allergic Reactions in the Emergency Department Theodore J. Gaeta, DO, MPH Sunday...
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Transcript of Anaphylaxis & Acute Allergic Reactions in the Emergency Department Theodore J. Gaeta, DO, MPH Sunday...
Anaphylaxis & Acute Allergic Reactions
in the Emergency Department
Theodore J. Gaeta, DO, MPH
Sunday Clark, MPH
Carlos A. Camargo, Jr., MD, DrPH
On behalf of the MARC Investigators
www.emnet-usa.org
Outline
Case Presentation
Prevalence and Natural History
Pathophysiology
ED Diagnosis and Management
Food-related Allergic Reactions
Post-care Plans
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Case Presentation
19 year old female with acute onset dyspnea
– Dyspnea, wheezing, vomiting and generalized flushing
– “minutes after eating a chocolate chip cookie”
– Past medical history: eczema
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Case Presentation (continued)
Vital signs
– SBP 80/p, P 124, R 40, T 98.8oF (37.1oC)
– Airway patent, diminished breath sound at the bases with wheezing in the upper fields
– Weak pulses with delayed capillary refill
– Diffuse erythematous rash observed and Medic Alert tag indicates peanut allergy
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Anaphylaxis
Multi-system syndrome resulting from mediator release
Acute onset
Varies from mild and self-limited to fatal
IgE and non-IgE mediated
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Anaphylaxis
Incidence
– 21 per 100,000 person-years (95% confidence interval [CI]: 17 - 25 per 100,000 person-years)1
– 10.5 per 100,000 person-years among children (95% CI: 8.1 – 13.3 per 100,000 person-years)2
11Yocum et al. J Allergy Clin Immunol 1999Yocum et al. J Allergy Clin Immunol 199922Bohlke et al. J Allergy Clin Immunol 2004Bohlke et al. J Allergy Clin Immunol 2004
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Estimated prevalence of Generalized Allergic Reaction*
Insect sting
Food
Drug
RCM
Allergen immuno Tx
Latex
All causes
of adults
of children
of adults
of cases
of patients
of adults
of adults
3%
1-3%
1%
0.1%
3%
1%
5%
*urticaria / angioedema or dyspnea or hypotension*urticaria / angioedema or dyspnea or hypotension
Anaphylaxis - Clinical Manifestations Cardiovascular:
– Tachycardia then hypotension – Shock: 50% intravascular volume loss – Bradycardia (4%) (transient or persistent)*– Myocardial ischemia
Lower respiratory: bronchoconstriction wheeze, cough, shortness of breath
Upper respiratory:– Laryngeal/pharyngeal edema – Rhinitis symptoms
Fisher. Anesth Intens Care 1986Fisher. Anesth Intens Care 1986www.emnet-usa.org
Anaphylaxis - Clinical Manifestations
Cutaneous:Pruritus, urticaria, angioedema, flushing
Gastrointestinal: Nausea, emesis, cramps, diarrhea
Ocular:Pruritus, tearing, redness
Genitourinary:Urinary urgency, uterine cramps
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Anaphylaxis -Temporal Pattern
Uniphasic
Biphasic – Initial allergic reaction– Recurrence of same manifestations up to 8
hours later
Protracted – Up to 32 hours – May not be prevented by glucocorticoids
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Anaphylaxis Mediators Histamine
– H1: smooth muscle contraction vasc permeability– H2: vascular permeability – H1+H2: vasodilatation, pruritus
Leukotrienes– Smooth muscle contraction– vascular permeability and dilatation
Nitric Oxide– Smooth muscle relaxation– vascular permeability and dilatation
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Causes of Anaphylaxis
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Causes of IgE-Mediated Anaphylaxis
Antibiotics and other medications
-lactams, tetracyclines, sulfas
Foreign proteins
Latex, hymenoptera venoms, heterologous sera, protamine, seminal plasma, chymopapain
Foods
Shellfish, peanuts, and tree nuts
Exercise induced
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Causes of Anaphylactoid Mediator Release
Complement activation– Iodinated dye– Aggregated IgG– IgA deficiency
Unknown mechanisms– Aspirin– Opiates– Local anesthetics
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Severity of Anaphylaxis
Risk Factors
Male
Consistent antigen administration
Shorter time elapsed since last reaction
Asthma
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Anaphylaxis Fatalities
Post Mortem Findings
Airway (laryngeal) and tissue (visceral) edema
Pulmonary hyperinflation
Tissue eosinophilia
Elevated serum tryptase
Myocardial injury
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Anaphylaxis Fatalities
Fatalities 4%
Increased risk blockade, severe hypotension,
bradycardia, sustained bronchospasm, poor response to epinephrine
– Adrenal insufficiency
– Asthma
– Coronary artery disease
Van der Klauw et al. Clin Exp Allergy 1996Van der Klauw et al. Clin Exp Allergy 1996www.emnet-usa.org
Anaphylaxis Fatalities
Bock SA et al. J Allergy Clin Immunol 2001Bock SA et al. J Allergy Clin Immunol 2001
0-9 10-19 20-29 30+0
10
20
30
40
50
60
Pe
rce
nta
ge
Age
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Anaphylaxis Differential Diagnosis
Vasovagal syncope
Systemic mastocytosis
Scombroid (fish) poisoning
Other causes of shock
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Anaphylaxis Diagnosis
Clinical features
Serum tryptase (measurable up to 6 hours)
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Anaphylaxis Treatment O2 , airway maintenance & IV fluids
Loose tourniquet? (to extremity for bee sting)
Epinephrine– 0.01 ml/kg (1:1000) IM q 10-20 min (max 0.3-0.5 ml)– In shock, 0.5- 5 mcg/min (1:10,000) IV to maintain SBP
H1 + H2 histamine receptor antagonists– Diphenhydramine, 1 mg/kg PO/ IM/ IV (max 75 mg)– Ranitidine
• Adult, 4 mg/kg PO (max 300 mg), 50 mg IM/IV q 6 h • Child, 1.5 mg/kg IM/IV (max 50 mg)
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Treatment (continued)
Corticosteroids– 1-2 mg/kg prednisone PO (max 75 mg)– 2 mg/kg methylpredisolone IV (max 250 mg)
• Not effective in protracted anaphylaxis • Effective in iodinated dye prophylaxis
Inhaled beta-agonists
Albuterol 2.5 mg q 15-20 min
Glucagon (consider if patient is on -blocker)
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Return to case
Placed on supplemental O2 and cardiac monitor
– IV access and fluid bolus
– Albuterol via nebulizer
– Epinephrine: 0.3 ml IM
– Diphenhydramine: 50 mg IV
– Ranitidine: 50 mg IV
– Methylpredisolone: 125 mg IV
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Response
Despite multiple doses of epinephrine and albuterol the patient remained in respiratory distress
Impending respiratory failure:Rapid sequence intubation
Transferred to ICU
Further history:The patient’s roommate presents a Medic Alert tag indicating peanut allergy
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Food-Related Allergic Reaction
Epidemiology
Fatal
Peanut
Schools
Exercise
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Frequency (USA): ~ 150 deaths / year Risk:
– Underlying asthma – Delayed epinephrine– Symptom denial – Previous severe reaction
History: known allergic food Key foods: peanut / tree nuts / shellfish Biphasic reaction Lack of cutaneous symptoms
Fatal Food Anaphylaxis
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Prevalence of Food Allergy
Perception by public: 20-25%
Confirmed allergy (oral challenge)– Adults: 1-2%– Infants/Children: 6-8%
Dye / preservative allergy (rare)
Specific Allergens– Dependent upon societal eating pattern– Milk (infants): 2.5%– Peanut / tree nuts in general population: 1.1%
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Diagnosis: History / Physical
History: symptoms, timing, reproducibility
Acute reactions vs. chronic disease
Diet details / symptom diary– Specific causal food(s)– “Hidden” ingredient(s)
Physical examination: evaluate disease severity
Identify general mechanism– Allergy vs. intolerance– IgE vs. non-IgE mediated
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Disposition
Most patients with allergic reactions can be discharged
Hospitalize or observe patients with airway angioedema, persistent brochospasm, hypoperfusion, cardiac problems, on -blockers
Observe 4 to 6 hours
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Risk Management for Anaphylaxis
Education– Allergen avoidance– Written emergency action plan– Resources (eg, FAAN website: www.foodallergy
.org)
Prescription for self-injectable epinephrine
Referral to an allergy specialist
Anaphylaxis – Operational Definition Two or more organ systems
– skin (e.g., hives) – respiratory (e.g., swelling of the lips, tongue, or
throat; trouble breathing or shortness of breath; stridor, wheezing)
– cardiovascular (e.g., hypotension, dizziness or fainting, altered mental status)
– gastrointestinal (e.g., trouble swallowing, abdominal pain)
Hypotension (SBP <100 mmHg)
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ObjectiveTo describe ED management of food allergy
MethodsThe Multicetner Airway Research Collaboration is a program within the Emergency Medicine Network (www.emnet-usa.org)
“State of the ED”
www.emnet-usa.orgClark et al. J Allergy Clin Immunol 2004Clark et al. J Allergy Clin Immunol 2004
EMNet Sites (137 US sites)
www.emnet-usa.org9/22/04
Methods (continued)
21 North American EDs participated in this study
Chart review of randomly selected patients presenting to the ED over a one year period with physician-diagnosed food allergy
ICD-9 codes– 693.1 (dermatitis due to food)– 995.0 (other anaphylactic shock)– 995.3 (allergy, unspecified)– 995.60 (allergy due to unspecified food) – 995.61-995.69 (allergy due to specified foods)
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Results 678 patients with physician-identified food
allergy were randomly selected for chart review
– 57% female, 43% white
– Mean age, 29 ± 18 years
92% had documentation of a specific food item as the cause of the current reaction
Only 41% of patients had documentation of a history of allergic reaction to the specific food that caused the current reaction
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Specific Foods*
* More than one option allowed. www.emnet-usa.org
Percentage 95% CI
Crustaceans 19 16 – 22
Peanut 12 9 – 14
Fruits and vegetables 12 10 – 15
Fish 10 8 – 12
Tree nuts 9 7 – 11
Milk 6 4 – 8
Eggs 2 1 – 4
Additives 1 0.5 – 2
Other foods 36 33 – 40
Presentation and ED Course n=678 95% CI
Arrived by ambulance (%) 18 16 – 22
Duration of symptoms 1 hour (%) 37 33 – 41
Received antihistamines in ED (%) 72 68 – 75
Received systemic steroids in ED (%) 48 45 – 52
Received epinephrine in ED (%) 16 13 – 19
Respiratory treatments in ED* (%) 33 29 – 37
Discharged to home (%) 97 95 – 98
* Inhaled -agonists and inhaled anticholinergicswww.emnet-usa.org
Outcomes
n=642 95% CI
Given discharge instructions to avoid offending allergen (%)
40
36 – 43
Given prescription for self-injectable epinephrine at ED or hospital discharge (%)
16
14 - 20
Referred to an allergist at ED or hospital discharge (%)
12
9 - 15
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M O R Q I S J L P H C E A N B K F T G D0
10
20
30
40
50
60
70
80
90
100
% g
ive
n in
stru
ctio
ns
to a
void
off
en
din
g a
llerg
en
at
dis
cha
rge
Site
Instructions to Avoid Offending Allergen
Goal = 100% Overall: 40% (95% CI, 36-43%)
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B F N Q D I E K P G L R C T S H U J M O0
10
20
30
40
50
60
70
80
90
100
% p
resc
ribe
d se
lf-in
ject
able
epi
nep
hrin
e a
t dis
cha
rge
Site
Self-injectable Epinephrine at Discharge
Goal = 100% Overall: 16% (95% CI, 14-20%)
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H K Q R E P B D I L S C G M N J A T F O0
10
20
30
40
50
60
70
80
90
100
% r
efer
red
to a
n al
lerg
ist a
t dis
char
ge
Site
Referred to Allergist at Discharge
Goal = 100% Overall: 12% (95% CI, 9-15%)
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Summary Although allergic reactions to food can be
life threatening, 18% of patients came to the ED by ambulance and only 3% were admitted
A variety of foods provoked the allergic reaction, with crustaceans and peanuts being the most common triggers
Only 16% of patients received a prescription for self-injectable epinephrine when leaving the ED
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Summary (continued)
Similarly, only 12% were referred to an allergist as part of discharge instructions
At a minimum, there is poor documentation of medications prescribed at ED discharge
Although guidelines suggest specific approaches for the emergency management of food allergy, concordance to these guidelines appears low
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Take Home
Keys to successful management
– Prompt recognition of the signs and symptoms of anaphylaxis
– Early administration of IM epinephrine
– Volume resuscitation
– Comfort and familiarity with 2nd line therapies
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Take Home (continued)
A successful post-care plan must include
– Education• Allergen avoidance• Written emergency action plan• Educational resources
(eg, www.foodallergy.org)
– Prescription for self-injectable epinephrine
– Referral to an allergy specialist
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