Transcript 08 – Anaphylaxis

EMT-PARAMEDIC AND
BEYOND
“Anaphylaxis”
Written by: William E. Gandy, JD, LP
Copyright 2005, All Rights Reserved
Edited By: Jane E. Dinsmore, A.A.S., LP
Antigen-Antibody Reaction
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To understand anaphylaxis, we must first
understand the basics of the antigenantibody reaction.
• Antigens
• Are substances that induce formation of antibodies.
• Are introduced into body by:
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Injection
Ingestion
Inhalation
Absorption
Antigen-Antibody Reaction
• Antibodies
• Are protective proteins developed in response to
antigens.
• Bind to the antigen that produced them.
• Neutralize and remove foreign substances.
• Invoke an immune response.
Immune Response
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Natural immunity is immunity present at
birth.
Acquired immunity develops from exposure
to a foreign substance or agent that serves
as an antigen.
Artificially induced immunity is obtained
typically through vaccination and
immunization.
Immunization

Immunization can produce two different
types of immunity.
• Passive
• Antibodies are injected and provide immediate but
short-lived protection.
• Active
• This type of immunization primes the body to make
its own antibodies.
Components of the Immune
System
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The Paramedic student must return to A&P
and review the following components and
systems involved in immunity.
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Lymphatic system
Leukocytes
Lymphocytes
Immunoglobulins
Mediators
Lymphatic System

The lymph system “cleans house”, so to
speak.
• It carries foreign material to the correct
“disposal site”.
• Lymph vessels vary in size.
• Lymph fluid enters the interstitial space from
capillaries (hydrostatic pressure).
• It then picks up debris and carries it out.
Lymph Nodes
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Lymph nodes are located throughout the
body including in the following locations:
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Mesenteric
Groin
Axillary
Under the jaw
Back of neck
Lymphocytes

The two primary categories of lymphocytes
are:
• B lymphocytes
• T lymphocytes
B Lymphocytes
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20% of B lymphocytes develop in the bone
marrow.
They bind to antigens and allow phagocytic
cells and T lymphocytes to destroy the
pathogen.
Memory cells earmark themselves
regarding the antigen and reserve the
information for future encounters.
T Lymphocytes

80% of all lymphocytes are produced in the
thymus.
• These respond to only one particular antigen.
• They recognize an antigen and latch onto it.
• T lymphocytes build up so as to be available if
it ever happens again.
• Helper cells, cytotoxic cells, memory cells,
regulatory cells, and natural killer T cells all may be
involved depending on the antigen.
Immunoglobulins

Immunoglobulins are basic antibodies made
of gamma globulin proteins. There are
several types including:
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IgM - antibody that responds immediately
IgG - antibody with “memory”
IgA - present in the mucous membranes
IgE - contributes to allergic and anaphylactic
responses
• IgD - present in lowest concentration
Mediators

Mediators are proteins that cause set
physiological responses. In this category
are:
• Histamine
• Leukocytosis
• Never Let Monkeys Eat Bananas
– Neutrophils, lymphocytes, monocytes. eosinophils,
basophils
• Chemical agents that bind leukocytes to the invading
allergen
Histamine
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Histamine is the principal chemical
mediator of an allergic reaction.
It is produced in the mast cells.
When it is released into the interstitial
space, the following reactions occur:
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Bronchoconstriction
Increased intestinal motility
Vasodilation
Increased vascular permeability
Histamine Receptors

H1 receptors
• Bronchoconstriction
• Contraction of the intestines
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H2 receptors
• Peripheral vasodilation
• Secretion of gastric acids
Assignment for Work on Your
Own:

Find examples of H1 and H2 blocking
drugs and describe their uses. (This ties
into your drug card work and will help you
retain and understand information from
your research for those cards on these types
of drugs.)
Allergic Response
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An allergic response is a normal protective
reaction.
However, it can become oversensitive and
cause an allergy.
Being allergic to lots of stuff is called
“atopy”, and people with lots of allergies
are said to be “atopic” individuals.
Allergic Response
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On a first time exposure, the allergic
response won’t occur in most cases.
Second and subsequent exposures produce a
reaction because of the build up of
antibodies from the initial and subsequent
exposures to the antigen.
• The tendency to be allergic to a specific antigen
MAY be inherited but it is not known for sure.
Anaphylaxis
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Common causes of anaphylactic reactions
may include:
• Some drugs have higher allergy rates than
others.
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Penicillins and cephalosporins
Aspirin
SMZ-TMP (Bactrim/Septra)
Vancomycin
NSAIDS
Anaphylaxis
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Other common causes:
• Foods
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Shellfish
Soybeans
Nuts
Wheat
Milk
Eggs
MSG
• Nitrates
• Nitrites
• Food dyes
Anaphylaxis
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And more common causes include:
• Hymenoptera stings
• Insect parts (check out your Hershey Bar)
• The FDA allows a small but maximum percentage
of insect parts and pieces and even rat feces in major
food manufacturing)
• Molds
• Radiographic contrast material
Anaphylaxis Presentation
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Skin
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flushing
itching (pruritis)
hives (urticaria)
swelling
cyanosis
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Respiratory System
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dyspnea
sneezing
coughing
wheezing
stridor
laryngeal edema
laryngospasm
bronchospasm
Anaphylaxis Presentation
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Cardiovascular system
• vasodilation
• increased heart rate
• decreased blood
pressure
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GI system
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nausea
vomiting
abdominal cramping
diarrhea
Anaphylaxis Presentation
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Nervous system
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dizziness
headache
convulsions
tearing
Anaphylaxis
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Angioedema of
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head
neck
face
upper airways
Anaphylaxis
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Flushing
Chills
Diaphoresis
Hoarseness
Stridor
Wheezing
The condition may progress in SECONDS
to Life Threatening!
Assessment of Anaphylaxis
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The EMS Professional must move quickly
through primary survey and secondary
surveys.
Gaining a history of the exposure is
extremely important.
Watch for worsening condition.
Watch for shock.
Assess vital signs and monitor closely.
Management of Anaphylaxis
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Support ventilations if indicated.
Oxygen by non-rebreather 15 LPM unless
breathing is inadequate, then assist.
Epinephrine is the primary drug in the
management of anaphylactic reactions.
• It is used to reverse the adverse effects of the
body’s immune response.
• Route of administration depends on severity of
the reaction.
Management of Anaphylaxis
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IV NS or RL and run wide open in most
cases.
• Large amounts of fluid may be necessary due to
systemic vasodilation and leaky vasculature
causing fluids to leak from the vessels into the
interstitial space (swelling).
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Don’t forget the external jugular veins as a
potential IV route if necessary.
Management of Anaphylaxis
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For a mild or moderate reaction:
• Epinephrine 1:1000 0.3 - 0.5 mg SQ
• This will be 0.3 to 0.5 mL of fluid
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For severe anaphylaxis:
• Epinephrine 1:10,000 0.3 - 0.5 mg IV is the
standard dosage
• This will be 3 to 5 mL of fluid
• Some recommend only 0.1 to 0.2 mg IV
• This will be 1 to 2 mL of fluid
Management of Anaphylaxis
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Epinephrine has a half life of only 3 - 5
minutes so you will most likely have to
readminister en route to the hospital.
• Watch for the effects wearing off.
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Epinephrine drip may be ordered
• 1 mg in 250 ml NS and run beginning at 8
gtt/min titrated to effect
Management of Anaphylaxis
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Consider a constricting venous band for
injected venoms dependent on local
protocol.
Also consider an intradermal injection of
0.15 to 0.25 mg epinephrine 1:1000 at the
site of the injected venom.
Management of Anaphylaxis
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Antihistamines are the 2nd line drug.
• Diphenhydramine (Benedryl)
• Non-selective H1 and H2 blocker
• Adult dose: 25 - 50 mg IV or IM
• Pediatric dose: 1 - 2 mg/kg IV or IM
• Hydroxyzine (Atarax, Vistaril)
• 25 - 100 mg IM ONLY
• Pedi 0.5 - 1 mg/kg/IM
Management of Anaphylaxis
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Antihistamines
• Promethazine (Phenergan)
• Adult: 12.5 - 25 mg IM or IV
• Pedi: 0.5 - 1 mg/kg IM or IV
• H2 Histamine blockers
• Cimetadine (Tagamet)
• Ranitidine (Zantac)
• These are less effective and slower
Management of Anaphylaxis
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Corticosteroids
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Methylprednisolone (Solu-Medrol)
125 - 250 mg IM or IV
Slow acting
Not first line
Beta Agonists can be used to easy
bronchoconstriction and difficulty
breathing.
• Albuterol (Ventolin, Proventil)
• 2.5 mg in 3 mL NS nebulized
Case Study
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You are called to a restaurant for a 30 year
old female who is dyspneic.
Your patient is hoarse but speaking.
Respirations are rapid and labored.
Radial pulse is thready and weak.
Patient is anxious but oriented.
BP 90/50, P 128, R 28 and labored.
Case Study
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Skin is erythematous with hives over trunk
and extremities.
ECG is sinus tachycardia.
Lips, tongue, and eyes are swollen.
Inspiratory and expiratory wheezes noted
throughout the lungs.
Oxygen sat is 86% on room air.
Case Study
• SAMPLE Survey:
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Allergic to shell fish.
Ate unknown soup at restaurant.
Takes birth control pills.
Throat started to close up and began itching, along
with her tongue, roof of mouth, and then body.
• Reaction began 10 minutes ago.
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What do you do NOW?????
Case Study
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Interventions
• Oxygen – high flow
• Epinephrine 0.3 mg SQ
• Consider giving Epi 1:10,000 IV instead if IV is
readily available
• IV NS or RL wide open
• Diphenhydramine 25 mg IV
• Consider Albuterol or another beta 2 inhaled
bronchodilator if wheezing does not go away
Case Study
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If you gave the correct interventions:
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BP 110/70
P 108
R 20
Wheezing disappears
Rash getting better
Patient feels much better
Case Study
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BUT, if you chose the incorrect
interventions or were too slow or too
conservative:
• Airway Obstruction
• Cardiac Arrest
Summary

An allergic reaction in and of itself is not a
bad thing. It has a purpose – to protect the
body. But an anaphylactic reaction is one in
which the body is in OVERKILL mode, and
it is a life-threatening emergency that
usually develops rapidly and kills rapidly.
The Paramedic must be astute and assured
while he/she is managing the condition.