Chapter 25 Immunologic Emergencies National EMS Education Standard

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 Ig. E 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

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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: • • Epi. Pen 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 ETCO 2 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 Epi. Pen 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/Shutter. Stock, 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.