ANAPHYLAXIS

1
ANAPHYLAXIS
2
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

3
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

4
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

5
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.

6
(No Transcript)
7
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.

8
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

9
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.

10
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

11
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

12
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.

13
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.

14
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.

15
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

16
Allergies

• Hypersensitivity is often used synonymously with
  the term allergy.
• Two types of hypersensitivity reactions
• 1. Delayed
• 2. Immediate

17
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

18
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

19
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.

20
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

21
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.

22
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

23
Immediate Hypersensitivity

• The goal of histamine release is to limit the
  bodys exposure to the antigen
• Bronchoconstriction decreases the possibility of
  the antigen entering through the respiratory
  tract
• Increased gastric acid production helps destroy
  ingested antigen

24
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

25
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.

26
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.

27
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

28
Clinical Features of Anaphylaxis

• SS 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

29
Assessment

• Initial assessment A-B-C
• Then followed by a detailed assessment

30
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.

31
Initial Assessment

• Evaluate neurological status A-V-P-U

32
Detailed Assessment

• Concentrate on the skin, the respiratory system,
  the cardiovascular system and the GI system.
• Assess for abnormalities and treat as indicated.

33
Management

• Airway Management
• Shock position
• Maintain body temperature

34
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

35
Epinephrine

• Primary medication for anaphylaxis.
• Reverses the effects of histamine
• Dose .3-.5 mg (11,000) SQ
• In severe cases .3-.5 mg (110,000) IV

36
(No Transcript)
37
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

38
(No Transcript)
39
Corticosteroids

• Adjunct therapy, to help suppress the
  inflammatory response associated with
  anaphylaxis.
• Most common Methylprednisolone (Solu-Medrol)
• Dose 125-250 mg, IV or IM

40
(No Transcript)