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ANAPHYLAXIS. Anaphylaxis Objectives. Upon completion the student will be able to: Define anaphylaxis Define antigen List ways an antigen can be introduced into the body Define antibody Describe the pathophysiology of allergic reactions and anaphylaxis. Anaphylaxis Objectives.

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anaphylaxis objectives
AnaphylaxisObjectives

Upon completion the student will be able to:

  • Define anaphylaxis
  • Define antigen
  • List ways an antigen can be introduced into the body
  • Define antibody
  • Describe the pathophysiology of allergic reactions and anaphylaxis
anaphylaxis objectives1
AnaphylaxisObjectives
  • Discuss the effects of allergic reactions and anaphylaxis on the following body systems:
  • Skin
  • Respiratory
  • Cardiovascular
  • Gastrointestinal
  • Nervous
  • Describe the clinical presentation of the patient suffering an allergic reaction and anaphylaxis
anaphylaxis objectives2
AnaphylaxisObjectives
  • Discuss the assessment of the patient suffering an allergic reaction and anaphylaxis
  • Describe the management of a patient with a severe allergic reaction
  • Describe the actions of the following medications, and relate their usage in the management of allergic reactions and anaphylaxis:
  • Oxygen
  • Epinephrine
  • Antihistamines
  • Corticosteroids
  • Beta Agonists
introduction
Introduction
  • An acute, generalized, and violent antigen-antibody reaction - the most severe from of an allergic reaction - that may be rapidly fatal even with prompt and appropriate emergency medical care.
  • Develops in seconds to minutes after ingestion, injection, inhalation or absorption of an antigenic substance.
immune system
Immune System
  • Plays a central role in allergies and anaphylaxis.
  • Components of the immune system can be found in the blood, the bone narrow, the connective tissues, and in the lymphatic system.
immune system1
Immune System
  • The immune response is a series of complex events with the goal being the destruction or inactivation of pathogens, abnormal cells, or foreign molecules such as toxins.
  • This can be accomplished through two mechanisms:

1. Cellular Immunity

2. Humoral Immunity

cellular immunity
Cellular Immunity
  • Derived from special leukocytes called t lymphocytes.
  • Originate in the thymus and are primarily responsible for fighting infections of biological agents living certain body cells, including tuberculosis, many viral infections, and most fungal infections.
  • Involves the movement of WBC to attack and eliminate.
humoral immunity
Humoral Immunity
  • More complicated.
  • Derived from B lymphocytes and results in the formation of antibodies. There are five classes of human antibodies (immunoglobulins)
  • They include:

1. IgM - antibody that responds immediately

humoral immunity1
Humoral Immunity

2. IgG - antibody that has “memory” and recognizes a repeatedly invading infection

3. IgA - antibody present in the mucous membranes

4. IgE - antibody contributing to allergic and anaphylactic responses

5. IgD - antibody present in the lowest concentration

humoral immunity2
Humoral Immunity
  • Begins with exposure of the body to an antigen. The antibodies seek out the invading antigen and combine, forming what is commonly called the antigen-antibody complex. This large complex is subsequently removed by scavenger cells such as macrophages.
humoral immunity3
Humoral Immunity
  • If the body has never been exposed to a particular antigen, the reaction is totally different.
  • Initial response to an antigen is called the primary response. It takes the cellular and humoral components several days to respond to a primary antigen exposure. But other antibodies assist and develop memories of the particular antigen.
humoral immunity4
Humoral Immunity
  • This way when the body is exposed to the same antigen again there is a secondary response which is much faster than the original.
allergies
Allergies
  • Initial exposure of an individual to an antigen is referred to as sensitization.
  • This results in an immune response. Subsequent exposure induces a much stronger secondary response
  • Hypersensitivity is an unexpected and exaggerated reaction to a particular antigen, resulting in some discomfort for the individual
allergies1
Allergies
  • Hypersensitivity is often used synonymously with the term allergy.
  • Two types of hypersensitivity reactions:

1. Delayed

2. Immediate

delayed hypersensitivity
Delayed Hypersensitivity
  • Result of cellular immunity and does not involve antibodies.
  • Occurs in hours and days following exposure
  • Most commonly results in skin rash and is often due to exposure to certain drugs and chemicals
  • Common example: rash from poison ivy
immediate hypersensitivity
Immediate Hypersensitivity
  • Examples of immediate hypersensitivity include: hay fever, drug allergies, food allergies and asthma.
  • Some individuals have an allergic tendency, known as atopy. This is usually genetic and characterized by the presence of IgE
  • An antigen that causes the release of IgE is referred to as an allergen
immediate hypersensitivity1
Immediate Hypersensitivity
  • After exposure to an allergen, large quantities of IgE are released.
  • IgE becomes attached to membranes of basophils and mast cells
  • Basophils and mast cells are specialized cells of the immune system which contain chemicals that assist in the immune response.
immediate hypersensitivity2
Immediate Hypersensitivity
  • When the allergen binds to IgE attached to the mast cells and basophils these cells release histamine, heparin.
  • Mast cells and basophils are referred to as granulocytes and histamine are stored in the granules of basophils and mast cells.
  • The release process of these substances is referred to as degranulation
immediate hypersensitivity3
Immediate Hypersensitivity
  • The reaction that takes place is referred to as an allergic reaction.
  • Histamine is the principal chemical mediator of an allergic reactions.
  • Histamine causes bronchoconstriction, increased intestinal motility, vasodilation, and increased vascular permeability.
immediate hypersensitivity4
Immediate Hypersensitivity
  • This increased permeability is what causes the leakage of fluid from the circulatory system into the surrounding tissue.
  • Two classes of histamine receptors:

1. H1 cause bronchoconstriction and contraction of the intestines

2. H2 cause peripheral vasodilation and secretion of gastric acids

immediate hypersensitivity5
Immediate Hypersensitivity
  • The goal of histamine release is to limit the body’s exposure to the antigen
  • Bronchoconstriction decreases the possibility of the antigen entering through the respiratory tract
  • Increased gastric acid production helps destroy ingested antigen
immediate hypersensitivity6
Immediate Hypersensitivity
  • Increased intestinal motility serves to move the antigen quickly through the GI system with minimal absorption
  • Vasodilation and capillary permeability help remove the allergen from the circulation where it has the potential to do the most harm
anaphylaxis1
Anaphylaxis
  • Usually occurs when a specific allergen is injected directly into the circulatory system.
  • The allergen is distributed widely throughout the body.
  • It then interacts with both basophils and mast cells, resulting in massive dumping of histamine.
anaphylaxis2
Anaphylaxis
  • Principle body systems affected by anaphylaxis are the skin, respiratory system, cardiovascular system, GI system and the nervous system.
  • Histamine causes widespread peripheral vasodilation, as well as increased permeability of the capillaries.
anaphylaxis3
Anaphylaxis
  • Because of this permeability and the resultant leakage people actually die from circulatory shock.
  • Another substance called slow-reacting substance of anaphylaxis is responsible for the spasms of the bronchioles
clinical features of anaphylaxis
Clinical Features of Anaphylaxis
  • S&S begin within 30-60 seconds following exposure
  • Severity of reaction is related to the speed of onset of symptoms
  • The faster the reaction the greater the severity
  • Itching and hives are the most common manifestations
assessment
Assessment
  • Initial assessment: A-B-C
  • Then followed by a detailed assessment
initial assessment
Initial Assessment
  • Evaluate the airway, most airway problems are associated with laryngeal edema. Take the necessary steps to manage the airway, including intubation or a surgical airway.
  • Evaluate breathing. Rate and depth. Lung sounds. Effort
  • Evaluate circulation. Pulse rate and strength. Blood pressure.
initial assessment1
Initial Assessment
  • Evaluate neurological status: A-V-P-U
detailed assessment
Detailed Assessment
  • Concentrate on the skin, the respiratory system, the cardiovascular system and the GI system.
  • Assess for abnormalities and treat as indicated.
management
Management
  • Airway Management
  • Shock position
  • Maintain body temperature
fluid and pharmacology
Fluid and Pharmacology
  • Fluid replacement is critical in preventing hypovolemia and hypotension, initiate at least 1 IV of NSS.
  • Principle treatment is pharmacological, which include:

1. Epinephrine

2. Antihistamines

3. Corticosteroids

epinephrine
Epinephrine
  • Primary medication for anaphylaxis.
  • Reverses the effects of histamine
  • Dose: .3-.5 mg (1:1,000) SQ
  • In severe cases .3-.5 mg (1:10,000) IV
antihistamines
Antihistamines
  • Second-line agents in anaphylaxis.
  • Block additional histamine from binding with the receptor sites.
  • Dephenhydramine (Benadryl) is the most frequently used antihistamine
  • Dose 25-50 mg slow IV push, or deep IM
corticosteroids
Corticosteroids
  • Adjunct therapy, to help suppress the inflammatory response associated with anaphylaxis.
  • Most common Methylprednisolone (Solu-Medrol)
  • Dose 125-250 mg, IV or IM
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