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Chapter 25
Immunologic
Emergencies
National EMS Education
Standard Competencies
Medicine
Integrates assessment findings with principles
of epidemiology and pathophysiology to
formulate a field impression and implement a
comprehensive treatment/disposition plan for
a patient with a medical complaint.
National EMS Education
Standard Competencies
Immunology
• Recognition and management of shock and
difficulty breathing related to
− Anaphylactic reactions
National EMS Education
Standard Competencies
Immunology
• Anatomy, physiology, pathophysiology,
assessment, and management of
hypersensitivity disorders and/or
emergencies
− Allergic and anaphylactic reactions
National EMS Education
Standard Competencies
Immunology
• Anatomy, physiology, epidemiology,
pathophysiology, psychosocial impact,
presentations, prognosis, and management
of common or major immunologic system
disorders and/or emergencies
− Hypersensitivity
− Allergic and anaphylactic reactions
National EMS Education
Standard Competencies
Immunology
•Anatomy, physiology, epidemiology,
pathophysiology, psychosocial impact,
presentations, prognosis, and management of
common or major immunologic system
disorders and/or emergencies (cont’d)
− Anaphylactoid reactions
− Collagen vascular diseases
− Transplant-related problems
Introduction
• 1,500 Americans die of acute allergic
reactions every year.
− Be prepared to treat acute airway obstruction
and cardiovascular collapse.
− Be able to distinguish between a regular
response and an allergic reaction.
Introduction
• Immune response problems include:
− Anaphylaxis
− Anaphylactoid reactions
− Allergic reactions
− Hypersensitivity
− Collagen vascular diseases
− Transplant-related disorders
Introduction
• Allergen:
Substance that
produces allergic
symptoms
• Antibody: Protein
produced in
response to an
antigen
Introduction
• Allergic reaction: An abnormal immune
response
− Local reaction: limited to a specific area
− Systemic reaction: occurs throughout the body
• Hypersensitivity: Inappropriate allergic
symptoms from a substance
Introduction
• Anaphylaxis: Systemic allergic reaction
− No exact cause in up to two thirds of patients
− Allergy-related diseases increase the risk.
− Other major factors include:
• The route of exposure
• The time between exposures
Introduction
Introduction
• Anaphylactoid reaction does not involve IgE
antibody mediation.
− May occur without previous exposure
− Patient presentation is the same.
Introduction
• Collagen vascular diseases
− Autoimmune disorders
− The body perceives its own collagen tissue as a
danger and attacks that tissue.
Introduction
• Collagen vascular diseases (cont’d)
− Systemic lupus erythematosus (SLE or lupus)
• Multisystem autoimmune disease
• Often diagnosed in women of childbearing age
• Can attack multiple systems
• Survival rate is currently at 15 years
Introduction
• Collagen vascular diseases (cont’d)
− Scleroderma
• Autoimmune connective tissue disease
• Can be either localized or systemic
• Patients are at greatest risk of dying from organ
damage during the first three years.
Introduction
• Patients with organ transplants receive
immune system suppression medications.
− Be prepared to identify rejection, infection, and
medication toxicity signs.
Introduction
• Infection is the
greatest threat in
an organ
transplant.
− Taking immunosuppressant
medications is
essential.
− Drug toxicity is also
a danger.
The Normal Immune Response
• Immune system protects body
− Cellular immunity: T cells attack and destroy
antigens.
− Humoral immunity: B cell lymphocytes produce
antibodies to attack foreign organisms.
Routes of Entry for Allergens
• Skin: injection or absorption
• Inhalation: patient breathes in allergens
• Ingestion: through the gastrointestinal tract
Physiology
• Primary response: Macrophages confront
and engulf antigens.
− Substances that cannot be identified are
recorded.
• Antibodies are intended to match the antigen and
inactivate it.
Physiology
• The body develops sensitivity.
− The body distributes details to the rest of the
body by placing the antibodies on:
• Basophils
• Mast cells
Physiology
• Basophils and
mast cells produce
chemical mediators
to fight antigens.
− Summon white
blood cells
− Increase blood flow
© Jones & Bartlett Learning
Physiology
Physiology
• Vaccine administration sends a small
amount of virus into the body.
− Body produce antibodies to it
− If an immunized person is later exposed, the
immune cells identify and kill the virus.
• Secondary response
Physiology
• Acquired immunity: Vaccine allows the body
to produce antibodies without becoming ill.
• Natural immunity: The body experiences the
full immune response.
• Herd immunity: When a group is immunized
Scene Size-Up
• Assess the scene for safety issues.
• Determine the nature of the illness.
− Check for potential exposure venues.
Primary Assessment
• Evaluate:
− Level of consciousness
− Respiratory system
− Circulatory system
− Mental status
− Skin
Primary Assessment
• Allergic reactions can be local or systemic.
• Categories:
− Mild: affecting a local area
− Moderate: mild signs spread through the body
− Severe: anaphylactic reactions
Primary Assessment
• Form a general impression.
− Observe for indication of severity.
− If the patient cannot speak, assess the airway.
− Level of conscious indicates:
• Severity of the reaction
• Oxygen and circulatory status
Primary Assessment
• Breathing and airway
− A noisy upper airway may be a sign of
impending airway occlusion.
• Check for stridor and hoarseness.
• The patient may report tightness in the throat.
Primary Assessment
• Breathing and airway (cont’d)
− Lung sounds are a predictor of severity.
− As hypoventilation begins, there will be:
• Diminished lung sounds
• Silence (ominous finding)
Primary Assessment
• Circulation
− Evaluate skin for histamine release symptoms,
which may include:
• Erythema
• Edema
• Pruritus
• Urticaria
Primary Assessment
• Transport decision
− May include:
• Remaining on the scene
• Initiating treatment in the vehicle
• Beginning immediate transport
• Calling for air transport
− Determine which facility to transport to.
History Taking
• Should be directed at the current complaint
− Does the patient have allergies?
− Have they ever had an allergic reaction?
• Ask about medications.
History Taking
• Intervention takes
precedence over
identifying antigen.
− Determine if
treatment was
administered:
• EpiPen
• Benadryl
• Beta-agonist inhaler
• Aerosolized
epinephrine
© Kumar Sriskandan/Alamy Images
Secondary Assessment
• Physical examinations
− Evaluate the respiratory system.
• Assess breathing.
• Auscultate the trachea and chest.
• Wheezing may be present.
• Prolonged respiratory difficulty may lead to death.
Secondary Assessment
• Physical examinations (cont’d)
− Assess the circulatory system.
• Hypoperfusion or respiratory distress indicates
severe allergic reaction.
− A systemic reaction may present as:
• Rash; red, hot skin; altered mental status
Secondary Assessment
• Vital signs
− Assess baseline vital signs.
− Airway obstruction: rapid, labored breathing
− Respiratory distress or shock: rapid respiratory
and pulse rates
Secondary Assessment
• Monitoring devices
− Cardiac monitor for dysrhythmias
− 12-lead ECG for cardiac ischemia
− ETCO2 for bronchoconstriction
− Pulse oximetry for oxygen saturation levels
Reassessment
• Should be done en route
− Focus on signs of airway compromise.
− Monitor the patient’s anxiety and the skin.
− Conduct serial vital signs.
− Reassess the chief complaint.
Reassessment
• Interventions
− Identify the amount of distress.
• Severe reactions require epinephrine and ventilatory
support.
• Milder reactions require supportive care.
Reassessment
• Interventions (cont’d)
− Recheck the interventions.
• A second dose of epinephrine may be needed.
− Identify and treat any changes in condition.
− In anaphylaxis cases, check interventions.
Reassessment
• Interventions (cont’d)
− Call in the patient report and include:
• The patient’s status
• Interventions completed
• The patient’s responses
• Estimated time of arrival
Anaphylactic Reactions
• Pathophysiology
− Immune system
becomes
hypersensitive.
• Identify harmless
substances as a
threat.
Courtesy of Carol B. Guerrero
Anaphylactic Reactions
• Pathophysiology (cont’d)
− When an invading substance enters the body,
mast cells release chemical mediators.
• In anaphylaxis, the effect involves more than one
body system.
Anaphylactic Reactions
• Pathophysiology
(cont’d)
− Histamine causes:
• Vasodilation
• Vascular
permeability
• Smooth muscle
contraction
• Decreased effects
of the heart
© Chuck Stewart, MD
Anaphylactic Reactions
• Pathophysiology (cont’d)
− Leukotrienes cause:
• Respiratory system becomes more dire
• Coronary vasoconstriction
• Increased vascular permeability
Anaphylactic Reactions
• Clinical symptoms
of anaphylaxis
− Patient
experiences three
types of shock:
• Cardiogenic shock
• Hypovolemic
shock
• Neurogenic shock
Anaphylactic Reactions
• Assessment
− It may be necessary to simultaneously:
• Assess the patient.
• Identify the problem.
• Intervene.
Anaphylactic Reactions
• Management
− Patients with allergic reaction signs but no
respiratory distress:
• Diphenhydramine (Benadryl)
• Monitor for changes.
Anaphylactic Reactions
• Management
(cont’d)
− If signs of allergic
reaction and
dyspnea:
• Deliver oxygen,
epinephrine, and
antihistamines.
• Monitor for
anaphylaxis.
− Remove offending
agent.
Anaphylactic Reactions
• Management (cont’d)
− Maintain airway and prepare to intubate.
• Cricothyrotomy may be necessary.
• Assess for stridor and hoarseness.
• Administer supplemental oxygen.
• Early administration of epinephrine should be a
priority.
Anaphylactic Reactions
• Management (cont’d)
− Administer epinephrine.
• Immediately stops the process
• Reverses the effects of the chemical mediators
• An EpiPen may have already been used.
Anaphylactic Reactions
• Management (cont’d)
− Maintain circulation.
• Administer 1 to 2 L of an isotonic solution.
• If there is no response up to 4 L may be needed.
• If there is still no response, consider a vasopressor.
Anaphylactic Reactions
• Management (cont’d)
− Initiate pharmacologic therapy.
− Be prepared to assist ventilation.
− Monitor for adverse effects to epinephrine.
− Reassess vital signs at least every 5 minutes.
Anaphylactic Reactions
• Management
(cont’d)
− If not accompanied
by hypotension or
airway
compromise, treat
with epinephrine.
• Adults: 0.3 to 0.5
mg
• Children: 0.001
mg/kg
Anaphylactic Reactions
• Management (cont’d)
− Antihistamine administration should only be
considered after epinephrine.
− Corticosteroids may prevent late reactions.
− Consider glucagon if no response to
epinephrine.
Anaphylactic Reactions
• Management (cont’d)
− Consider vasopressors if no response to fluids.
− If bronchospasm is present, consider inhaled
beta-adrenergic agents.
− Psychological support is crucial.
Collagen Vascular Diseases
• Pathophysiology
− Systemic lupus erythematosus (SLE or lupus)
• Multisystem autoimmune disease
• Monitor for life threats.
• Patients may be on immunosuppressive
medications.
Collagen Vascular Diseases
• Pathophysiology (cont’d)
− Scleroderma
• Presents with tightening, thickening, and scarring
• Often include symptoms of Raynaud phenomenon
• Damage to the heart muscle is a major
complication.
Collagen Vascular Diseases
• Assessment
− Rule out life threats.
• Management
− Treat any life threats.
− Monitor for signs of infection.
Organ Transplant Disorders
• Pathophysiology
− Immune system tries to reject the organ.
− Patients are given antirejection medications.
− Address priorities in caring for specific
transplanted organs.
Organ Transplant Disorders
• Heart transplant
− The recipient’s heart is usually removed, but
may be left in place.
− Atropine is not indicated.
− Sympathomimetic drugs work well.
Organ Transplant Disorders
• Heart transplant (cont’d)
− Signs and symptoms of infection may include:
• Shortness of breath
• Hypotension pressure
• Poorly controlled hypertension
• A new dysrhythmia
Organ Transplant Disorders
• Liver transplant
− The loss of function causes rapid deterioration.
− Watch for infection.
• Kidney transplant
− Infection is a major concern.
− Recipients tend to develop hepatitis C and later
liver disease.
Organ Transplant Disorders
• Lung transplant
− Usually performed unilaterally
− Signs of rejection may include:
• Cough
• Dyspnea
• Rales
• Decrease in oxygenation
Organ Transplant Disorders
• Pancreas transplant
− More complications and a lower survival rate at
1 year than other transplants
− Exocrine component is usually drained into the
bladder, along with the bicarbonate
− Infection and rejection are common problems.
Organ Transplant Disorders
• Assessment
− Be aware of subtle signs and symptoms.
− Signs and symptoms vary.
− Consider calling the transplant center for any
questions.
Organ Transplant Disorders
• Management
− Priorities:
• Organ transplanted
• Medications
• Recognition of infection or rejection
Organ Transplant Disorders
• Management (cont’d)
− Understand how medications will interact and
how they will be metabolized.
− Monitor for infection or organ rejection.
− Consider transport to the transplant facility
when possible.
Patient Education
• Anaphylaxis
− Avoid the antigen.
− Notify all health personnel.
− Wear identification tags or bracelets.
− Carry an anaphylaxis kit.
− Report symptoms early.
Patient Education
• Collagen vascular diseases and organ
transplants
− Encourage self-monitoring.
− Consult a physician before taking a new
medication.
− Comply with the immunosuppressive regimen.
− Know who to contact.
Summary
• An antigen is a substance the body
recognizes as foreign.
• The immune system is responsible for the
antigen–antibody response.
• An allergic response occurs when the body
produces the antigen–antibody response
when exposed to a normally harmless
substance.
Summary
• Anaphylaxis is an extreme form of systemic
allergic response involving two or more
body systems.
• A person must be sensitized to an antigen
before an allergic or anaphylactic response
occurs.
• An anaphylactoid reaction may occur with
no previous exposure of the allergen.
Summary
• Exposure can come from injection,
absorption, inhalation, and ingestion.
• Mast cells release chemical mediators to
stimulate the allergic reaction.
• Chemical mediators produce signs and
symptoms on the skin, cardiovascular,
respiratory, neurologic, and gastrointestinal
systems.
Summary
• Skin effects include erythema, urticaria, and
pruritus.
• Cardiovascular effects include vasodilation,
hypotension, decreased cardiac output,
cardiac ischemia, and dysrhythmias.
• Respiratory effects include upper airway
edema and stridor, hoarseness,
bronchoconstriction, increased bronchial
secretions, wheezes, and hypoxia.
Summary
• Neurologic systems include altered level of
consciousness, anxiety, restlessness,
combativeness, and unconsciousness.
• Gastrointestinal symptoms include nausea,
vomiting, diarrhea, and cramping.
• The assessment should include evaluating
the scene, patient history, level of
consciousness, upper airway, lower airway,
skin, and vital signs.
Summary
• To treat anaphylaxis:
− Remove the offending agent.
− Maintain airway.
− Administer medications.
− Resuscitate with IV fluids.
− Initiate rapid transport.
Summary
• Epinephrine is the first-line drug therapy.
• Patient education is essential.
• Collagen vascular and other autoimmune
diseases may require medications to
suppress the immune system.
• It is important to know the treatment
priorities for patients with organ transplant
disorders.
Credits
• Chapter opener: © Jones & Bartlett Learning.
Courtesy of MIEMSS.
• Backgrounds: Gold—Jones & Bartlett Learning.
Courtesy of MIEMSS; Purple—Jones & Bartlett
Learning. Courtesy of MIEMSS; Green—Courtesy
of Rhonda Beck; Red—© Margo
Harrison/ShutterStock, Inc.
• Unless otherwise indicated, all photographs and
illustrations are under copyright of Jones & Bartlett
Learning, courtesy of Maryland Institute for Emergency
Medical Services Systems, or have been provided by the
American Academy of Orthopaedic Surgeons.