Chapter 25 Immunologic Emergencies

With anaphylaxis monitor for a ______________ waveform on the ETco2 monitor, which may be due to bronchoconstriction.

"shark fin" v. A pulse oximetry may show low oxygen saturation.

With anaphylaxis the blood vessels dilate, making the vascular volume totally inadequate and causing hypotension. (a) In response, the heart rate increases, causing:

(1) Tachycardia (2) Flushed skin (3) Hypotension

A second dose of epinephrine or infusion may be needed if the patient has:

(a) Decreasing mental status (b) Increased difficulty breathing (c) Decreased blood pressure d. Identify and treat any changes in condition.

For patients who have signs of an allergic reaction but no respiratory distress or dyspnea

(a) Drug of choice is diphenhydramine (Benadryl). (b) Continue to monitor for changes in condition. (c) Most patients in this group will recover with no further problems.

Administration of epinephrine for Anaphylactic Reactions with an auto-injector involves:

(a) Firmly stabilizing the leg prior to and during administration (particularly in young children) (b) Pushing the auto-injector firmly against the anterolateral aspect of the thigh (c) Holding the injector in place for approximately 3 seconds until the medication is injected

Evaluate the respiratory system. i. Thoroughly assess breathing and note any:

(a) Increased work of breathing (b) Use of accessory muscles (c) Head bobbing (d) Tripod positioning (e) Nostril flaring (f) Grunting ii. Auscultate the trachea and chest. iii. Stridor and wheezing may be present.

For patients who are not stable initially, are deteriorating, or have a history of deterioration

(a) Remove the offending agent. (b) When possible, separate the patient from the situation involving the antigen.

Respiratory symptoms are the most common complaints. May include:

(a) Shortness of breath or dyspnea (b) Tightness in the throat and chest (c) Stridor and hoarseness ii. May involve upper airway and lower airway iii. Symptoms may progress slowly or very rapidly

Breathing becomes more difficult, and the patient may stop breathing. iv. Prolonged respiratory difficulty may cause:

(a) Tachycardia (b) Shock (c) Respiratory failure (d) Death

Diseases related to allergies, or atopic diseases, include:

* Allergic rhinitis * Asthma * Atopic dermatitis. -If possible, note route and time of exposure.

The body records details to assist in substance identification and distributes them to the rest of the body by placing the antibodies on:

-Basophils (found in specific sites within tissues) - Mast cells (found in the connective tissues, bronchi, gastrointestinal mucosa, and other border areas)

Invasion through the skin may occur by way of:

-Injection: The substance pierces the skin and deposits foreign material. Example: Bee and hornet stings -Absorption: Foreign material is slowly absorbed through the skin. Including through vaginal wall

Antibody:

A protein produced by the body in response to an antigen a. This protein (globulin), also known as immunoglobulin (Ig), is found in plasma. b. The IgE antibody is the primary antibody responsible for allergic reactions.

Allergen:

A substance that produces allergic symptoms a. Usually harmless and does not pose a threat to others b. Examples: Eggs, peanuts, antibiotics, insect venom

Biphasic reaction:

A two-phase allergic reaction in which the patient's symptoms improved and then reappear without secondary exposure to the trigger

Ingestion:

Allergens attack via the gastrointestinal tract.

Four types of Hypersensitivity:

Allergic reaction biphasic reaction prolonged reaction anaphylactoid reaction

Local reaction:

Allergic response is limited to a specific area - Example: Swelling around an insect bite

Allergic reaction:

An abnormal immune response that the body develops when the person has been previously exposed or sensitized to a substance or allergen

Anaphylaxis:

An extreme systemic allergic reaction involving two or more body systems

Anaphylaxis:

Anaphylaxis symptoms that continue over time (5 to 72 hours) -Anaphylactoid reaction does not involve IgE antibody mediation. - May occur without previous exposure to the allergy agent -Causes include some contrasts given before radiography, morphine-derivative medications, and aspirin. -Patient presentation is the same for anaphylaxis and anaphylactoid reactions. no prior sensitization required

The body protects itself through two types of systems:

Cellular immunity (cell-mediated immunity) -The body produces T cells to attack and destroy invaders. Humoral immunity - B cell lymphocytes produce antibodies that dissolve in the plasma and lymph to attack foreign organisms.

Inhalation:

Exposure occurs when the patient breathes in allergens through the respiratory tract. The foreign substances advance through the respiratory system to the lungs. -Examples: Cat hair, dander, peanuts

_____________ causes the local blood vessels to dilate and capillaries to leak.

Histamine ii. Leukotrienes cause additional dilation and leaking.

_______________ occurs when a person's immune system reacts with exaggerated or inappropriate allergic symptoms from a substance the body perceives to be harmful.

Hypersensitivity

Immune response problems include:

Hypersensitivity Allergic reactions Anaphylaxis Biphasic allergic reactions Anaphylactoid reactions Collagen vascular diseases Transplant-related disorders

_________________ or respiratory distress indicates the allergic reaction may be severe enough to cause death.

Hypoperfusion

Histamine release causes:

Immediate vasodilation, often presenting as erythematous skin and hypotension Vascular permeability, resulting in edema, fluid secretion, and fluid loss (a) Edema can present as urticaria, airway constriction, and increased fluids in the airway. Smooth muscle contraction in the respiratory and gastrointestinal systems, resulting in laryngospasm, bronchospasm, and abdominal cramping Decrease in the inotropic effects of the heart (a) When coupled with vasodilation, this may lead to profound hypotension. (b) Dysrhythmias due to hypoperfusion and hypoxia are common.

The cells that produce immunity are found in the:

Lymph nodes Spleen Gastrointestinal tract -The goal is to intercept foreign organisms as they enter the body.

Systemic reaction:

Occurs throughout the body and may affect multiple body systems -Example: Swelling and hives all over the body after ingesting an allergen

_________________ administration should be considered for patients with signs of anaphylaxis or cardiovascular or respiratory compromise, whether respiratory distress is present or not.

Oxygen

Later responses from leukotrienes compound the effects of histamine, and may cause:

Respiratory system to become more dire Coronary vasoconstriction, contributing to a worsening cardiac condition and myocardial irritability Increased vascular permeability, causing further hypoperfusion Other chemical mediators continue to worsen the signs and symptoms, and the patient may not survive without immediate intervention.

______________ reactions require ventilatory support and/or fluid resuscitation.

Severe

With Immunologic Emergencies to save the patient's life you may have to simultaneously:

a. Assess the patient. b. Identify the problem. c. Intervene within seconds of arriving on the scene.

Patient history should include:

a. Investigation of the chief complaint b. SAMPLE c. OPQRST The history should be directed at the current complaint. If a life threat exists, some steps can be collected later.

Allergic symptoms are as varied as the allergens themselves. Assessment should include evaluations of:

a. Level of consciousness b. The respiratory system c. The circulatory system d. Mental status e. The skin

Allergic reactions are categorized as:

a. Mild reactions, affecting a local body area i. Examples: Itchy water eyes, a rash, or slight congestion b. Moderate reactions, beginning with mild signs and symptoms and spreading to other parts of the body i. Example: Initial itchy water eyes, followed by trouble breathing and tightness in the chest c. Severe reactions (anaphylactic reactions), resulting in possible life-threatening emergencies -These reactions are systemic. ii. Example: Congestion that progresses to respiratory distress and hypotension iii. Onset may be sudden.

The body develops sensitivity, the ability to recognize the foreign substance when it is encountered

again.

Systemic effects of the chemical mediators cause the signs and symptoms of

allergic and anaphylactic reactions.

Early epinephrine administration is a priority for

anaphylactic reaction.

Use tools such as a cardiac monitor for dysrhythmias associated with

anaphylaxis. ii. Consider using a 12-lead ECG to monitor for cardiac ischemia. iii. Monitor for elevated end-tidal carbon dioxide levels.

White blood cells help engulf and destroy the

antigen. Platelets begin to collect and clump together.

A severe reaction can occur at the second exposure to an

antigen. e. Ask whether any interventions have been taken. f. Ask about medications.

If the patient cannot speak, assess the airway before

assuming a neurologic problem.

Prostoglndins cause

bronchioconstriction

When an invading substance enters the body, mast cells release

chemical mediators.

Proteoglycans advance

coagulation, DIC

WIth anaphylaxis cardiovascular symptoms are serious complications. Histamine and leukotrienes ______________ contractility of the heart.

decrease The resulting decrease in cardiac output is complicated by vasodilation and increased capillary permeability. Perfusion decreases, leading to ischemia and potential cardiac dysrhythmias. Fluid leaks from the capillaries. As much as 50% of vascular volume can be lost within 10 minutes of exposure.

If you can't determine another cause of the symptoms and the patient continues to present with anaphylactic symptoms, do not

delay treatment for a more complete diagnosis.

IM administration of ___________________ in the anterolateral thigh is the drug and route of choice for Anaphylactic Reactions

epinephrine Do not delay administration of epinephrine. Many patients will require more than one dose of epinephrine to reverse the reaction. Additional IM doses may be repeated every 5 to 15 minutes as needed.

Wheezing occurs when

excessive fluid and mucus are secreted into the bronchial passages.

The immune system protects the human body from

foreign substances and organisms.

The basophils and mast cells produce chemical mediators that contain _________ filled with powerful substances to fight the antigens.

granules -The granules remain inactive until the body is invaded by a previously identified foreign substance. -If an antigen enters the body and combines with one of the antibodies, the granules are detonated. -Chemical mediators are released into surrounding tissue and the bloodstream.

With Anaphylactic Reactions If there is no response to the IM doses, administer an IV infusion of epinephrine in conjunction with an IV fluid bolus to support the __________________ status as needed.

hemodynamic Endotracheal administration may be considered if other routes are not available. Many patients and EMTs carry an EpiPen.

Assess the circulatory system. i. Monitor for signs of

hemodynamic compromise. (a) Including blood pressure, pulse rate, cardiac monitoring, and pulse oximetry

Muscles around the passages tighten because of the release of __________ and leukotrienes induced by the allergen.

histamines

With Anaphylactic reactions the immune system becomes ________________ to one or more substances that should not be defined as harmful.

hypersensitive Immune cells of the allergic person are more sensitive than those of a person without allergies.

A systemic reaction may present as:

i. A rapidly spreading rash ii. Red, hot skin iii. An altered mental status

Gastrointestinal symptoms of anaphylaxis may include:

i. Abdominal cramping ii. Nausea iii. Bloating iv. Vomiting v. Abdominal distention vi. Profuse, watery diarrhea

A patient with anaphylaxis experiences three types of shock:

i. Cardiogenic shock due to decreased cardiac output ii. Hypovolemic shock due to leaking fluids iii. Neurogenic shock due to inability of blood vessels to constrict

In severe reactions, intervention takes precedence over identifying the antigen. a. Ask when the symptoms began. b. Direct your assessment to potential life threats. c. Ask about feelings of dyspnea to determine any airway concerns. d. Determine if any treatment has been administered by the patient or first responders, such as:

i. EpiPen ii. Diphenhydramine (Benadryl) iii. An inhaler with a beta-agonist iv. Aerosolized epinephrine

Monitor closely for changes in circulation. Evaluate the skin for histamine release symptoms commonly associated with an anaphylactic reaction:

i. Erythema ii. Rashes iii. Edema iv. Moisture v. Pruritus vi. Urticaria Note that anaphylaxis can occur without these common skin changes. The patient may also show pallor and cyanosis.

Skin symptoms are often the first indications of anaphylaxis and may include:

i. Feeling warm and flushed ii. Pruritus (itching), indicating vasodilation and capillary leaking (a) The area around the eyes is especially susceptible. iii. Swelling of the face and tongue (angioedema), contributing to airway compromise iv. Edema of the hands and feet v. Urticaria (hives) from histamine release

Central nervous system symptoms of anaphylaxis may include:

i. Headache ii. Dizziness iii. Confusion iv. Anxiety v. A sense of "impending doom" Requires rapid assessment and treatment

Focus on signs of airway compromise, including:

i. Increasing work of breathing ii. Stridor iii. Wheezing

Ask questions regarding risk factors for severe anaphylaxis, such as:

i. Peanut and tree nut allergy history ii. Preexisting respiratory or cardiovascular disease iii. Asthma iv. Delayed administration of epinephrine v. Previous biphasic anaphylactic reactions vi. Advanced age vii. Mast cell disease

Assess baseline vital signs, including:

i. Pulse ii. Respirations iii. Blood pressure iv. Skin v. Pupils vi. Oxygen saturation

When completing the primary assessment, begin making transport decisions such as:

i. Remaining on the scene ii. Loading the patient and initiating treatment in the vehicle iii. Beginning immediate transport iv. Calling for air transport Also determine which facility the patient should be transported to.

Monitor the skin for:

i. Signs of shock (pallor and diaphoresis) ii. Flushing Conduct serial vital signs, with any increase in respiratory or pulse rate or decrease in blood pressure noted. Continue to reassess the chief complaint.

Assess the skin for:

i. Swelling ii. Rash iii. Hives iv. Signs of the reaction source (bite, sting, contact marks)

Rapidly differentiate between anaphylaxis and other conditions with similar symptoms, which may include:

i. Syncope ii. Flushing iii. Red man syndrome iv. Severe anxiety and respiratory distress v. Wheezing and respiratory distress vi. Monosodium glutamate poisoning vii. Scombroid fish poisoning viii. Transfusion-related acute lung injury ix. ACE inhibitor angioedema

Call in the patient report to the receiving facility during transport to give staff time to prepare by giving them:

i. The patient's status ii. Interventions completed iii. The patient's responses

The chemical mediators begin and maintain the

immune response. i. They summon more white blood cells to the area. ii. They increase blood flow by dilating the blood vessels and increasing capillary permeability in the area. While useful in a limited area, it can be extremely dangerous when spread throughout the body.

For Anaphylactic Reactions Insert at least one large-bore IV catheter to administer an

isotonic solution (lactated Ringer or normal saline). Ideally, you should place two IV lines en route to the emergency department. If IV access is not available, use IO access. Be prepared to repeat the doses as needed in the hypotensive patient. If there is no response, consider administering a vasopressor in conjunction with fluid administration. Avoid fluid overload, especially in the cardiac patient.

Airway obstruction is indicated by rapid,

labored breathing.

The body initiates a series of responses when a foreign substance enters the body. The primary response begins when

macrophages confront and engulf the invading substances.

If the body cannot identify the substance, the immune cells record the features of the outside substances and design specific proteins to

match each substance. -These proteins (antibodies) are intended to match the foreign substance (antigen) and inactivate it.

In anaphylaxis, the effect of the chemical mediators involves

more than one body system. An initial effect may be followed by secondary effects a few hours later.

Anaphylactic Reactions Initiate ________________ therapy.

pharmacologic Administer high-flow oxygen, epinephrine, antihistamines, anti-inflammatory and immunosuppressant agents, and a vasopressor.

A weak, thready, or absent radial pulse is indicative of

potential cardiovascular collapse. Ensure early recognition of shock and initiation of immediate treatment.

With Immunologic Emergencies assess the scene for safety issues. Determine the nature of the illness by checking for

potential exposure venues. a. Example: A bee sting in a garden b. Example: Shellfish exposure in a seafood restaurant

Monitor the patient's anxiety, as this may be an indicator of a

progressing reaction.

Decreased circulation and exposure to carbon monoxide can alter

pulse oximetry readings.

Respiratory distress or systemic shock are indicated by

rapid respiratory and pulse rates.

When the body is exposed to a foreign substance, the immune system responds, resulting in a localized or systemic

reaction.

Anaphylaxis presents with

respiratory symptoms and hypotension. i. Gastrointestinal symptoms (abnormal cramping, nausea, vomiting, diarrhea) may be present. ii. If symptoms are life threatening, perform secondary assessment after life threats are addressed and you are en route to the hospital.

Common signs of hypoxia include

restlessness, confusion, anxiety, and combativeness.

Some EpiPens have two doses—do not discard the

second dose. f. Ask about less common causes of anaphylaxis. i. Such as exercise-induced reactions or seminal fluid reactions

Breath sounds are a predictor of

severity. i. Initially the patient will present with wheezing. ii. As hypoventilation begins, there will be diminished lung sounds or silence—an ominous finding. Requires immediate intervention

Milder reactions, without respiratory or cardiovascular distress, may require only

supportive care. In situations of mild or severe, the patient should be transported to a medical facility for further evaluation.

Stridor occurs when

swelling in the upper airway closes off the airway and can lead to total obstruction.

A noisy upper airway may be an early sign of impending airway occlusion due to

swelling. i. Check for stridor and hoarseness. ii. The patient may report tightness or a "lump" in the throat. iii. Observe for: (a) Difficulty speaking (b) Noisy airway (c) Tachypnea (d) Labored breathing (e) Accessory muscle use (f) Abnormal retractions (g) Prolonged expiration

Assessment may direct treatment and should include a

systematic head-to-toe or focused assessment.

Allergic reactions can be local or

systemic. 5

Assessing for the presence of stridor and hoarseness should indicate the severity of

the airway compromise.

Level of conscious indicates the severity of the reaction, as well as

the patient's oxygen and circulatory status.

Substances enter the body through

the skin, respiratory tract, or the gastrointestinal tract.

Immediate airway evaluation and management is needed if

there is any change in mental status of an anaphylactic patient.

No Routes of Entry for Allergens is determined in up to

two-thirds of patients.

Be cautious in changing the position of an anaphylactic patient from a supine to an

upright or standing position. Use an appropriate oxygen device for supplemental oxygen, and consider early transport. Early administration of epinephrine should be a priority.