Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Paramedic Care:Principles & Practice

Volume 3Medical Emergencies

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Chapter 5 Allergies and Anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Topics

Pathophysiology

Assessment Findings in Anaphylaxis

Management of Anaphylaxis

Management of Allergic Reactions

Patient Education

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Introduction

Allergic Reaction– An exaggerated

response by the immune system to a foreign substance

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Introduction

Anaphylaxis– An unusual or exaggerated allergic reaction– A life-threatening emergency

Injected penicillin and bee and wasp (Hymenoptera) stings are the two most common causes of fatal anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Pathophysiology

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Pathophysiology

The Immune System– The goal of the immune response is destruction

or inactivation of:PathogensAbnormal cellsForeign molecules

– Cellular Immunity– Humoral Immunity

Antibodies (Immunoglobulins)IgA, IgD, IgE, IgG, IgM

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Pathophysiology

Immune Response– Exposure to antigen produces primary

response. with general antibodiesImmune system develops antigen-specific antibodies and memory

– Future exposures generate a faster secondary response

Natural and Acquired Immunity

Induced Active Immunity

Active and Passive Immunity

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Allergies

Sensitization– Initial exposure of an individual to an antigen

Hypersensitivity– Delayed

Results from cellular immunity and does not involve antibodies

Commonly results in skin rash

Results from exposure to certain drugs or chemicals

– ImmediateExposure quickly results in secondary response

More severe than delayed hypersensitivity

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Allergies

Allergen– Exposure generates secondary response

Large quantities of IgE are released

Allergen binds to IgE, causing chemical releaseRelease is “allergic reaction”

Includes histamines, heparin, and other substances that are designed to minimize the body’s exposure to an antigen

Histamine causes bronchoconstriction, vasodilation, increased gastric motility, and increased vascular permeability

Angioneurotic edema

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Allergic Response

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Anaphylaxis

Causes– Antigen that causes release of the IgE

antibodies is referred to as an allergen

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Anaphylaxis

Causes– Injections

Most anaphylaxis results from injected allergenAllergen rapidly distributed throughout the body, resulting in massive histamine release

Parenteral penicillin injections and insect stingsAffects cardiovascular, respiratory, gastrointestinal, and integumentary systemsSignificant plasma loss through increased vascular permeabilitySlow-reacting substance of anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Assessment Findings in Anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Assessment Findings in Anaphylaxis

Focused History and Physical Exam– Focused History

SAMPLE and OPQRST HistoryRapid onset, usually 30–60 seconds following exposureSpeed of reaction is indicative of severityPrevious allergies and reactions

– Physical ExamPresence of severe respiratory difficulty is key to differentiating anaphylaxis from allergic reaction

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Physical Exam– Facial or laryngeal

edema– Abnormal breath

sounds– Hives and urticaria– Hyperactive bowel

sounds– Vital sign deterioration

as the reaction progresses

Assessment Findings in Anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Pathophysiology of Anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management of Anaphylaxis

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management of Anaphylaxis

Scene Safety:– Consider the possibility of trauma

Protect the airway– Use airway adjuncts with care– Intubate early in severe cases to prevent total

occlusion of the airway– Be prepared to place a surgical airway

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management of Anaphylaxis

Support breathing– High-flow, high-concentration oxygen or assisted

ventilation if indicated

Establish IV access– Patient may be volume-depleted due to “third

spacing” of fluidAdminister crystalloid solution at appropriate rate

Place a second IV line if indicated

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management of Anaphylaxis

Administer medications:– Oxygen– Epinephrine– Antihistamines– Corticosteroids– Vasopressors– Beta-agonists– Other agents

Psychological support

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management of Allergic Reactions

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Scene safetyProtect the airwaySupport breathingEstablish IV accessAdminister medications:– Antihistamines– Epinephrine

Management of Allergic Reactions

© Craig Jackson/In the Dark Photography

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Management ofAnaphylaxis and Allergic Reactions

Click here to view the management of Anaphylaxis and Allergic Reactions.

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Patient Education

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Patient Education

Prevention of Reactions

Recognition of Signs/Symptoms– Patient-initiated treatment

Epinephrine auto-injectors

Desensitization

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Summary

Pathophysiology

Assessment Findings in Anaphylaxis

Management of Anaphylaxis

Management of Allergic Reactions

Patient Education