Download IMMUNITY

IMMUNITY
Week 3
Immunity
• Human body constantly threatened by
– Foreign substances
– Infectious agents
– Abnormal cells
• Function of immune system
– Protect body from foreign antigens
– Identify and destroy potentially harmful cells
– Remove cellular debris
Immunity, continued
• Body’s natural or induced response to infection
– Immunocompetent clients
– Hypersensitivity
– Autoimmune disorders
– Immunodeficiency
• Understanding immune system
– Teaching clients and families
Immune System
• Complex network
• Performs several functions
– Defends and protects body from infection
– Removes and destroys dead/damaged cells
– Identifies/destroys malignant cells
• Activated by external agents
– Inflammation nonspecific response
– Ability to differentiate host from foreign tissue
Components of the
Immune System
• Leukocytes (WBCs)
– Primary cells
– Derived from stem cells in bone marrow
– Use circulation to transport to site
– Normal number: 4,500–10,000 cells/mm3
– Leukocytosis in presence of infection
– Leukopenia
Types of Leukocytes
• Granulocytes  60–80%
– Myeloid stem cells of bone marrow
– Protect body from microorganisms
– Three types
• Neutrophills
• Eosinophils
• Basophils
Types of Leukocytes, continued
• Antigen-presenting cells (APCs)
– Initiate immune response
– Actively phagocytic
– Three types
 Monocytes
 Macrophages
 Dendritic cells
Figure 14-1 The development and differentiation of leukocytes from hemocytoblasts.
Types of Leukocytes, continued
• Lymphocytes
– Effector and regulator cells of specific responses
– Constantly circulate
– Three types
• T cells
• B cells
• Natural killer cells
Figure 14-2 The development and differentiation of lymphocytes from lymphoid stem cell (lymphoblasts).
Antigens
• Provoke specific immune response
• Complete antigens have 2 characteristics
– Immunogenicity
– Specific reactivity
• Primary immune response
Figure 14-3 The primary immune response encompasses a cascade of events that involve humoral immunity and
cellular immunity.
Antibodies
• Classes of antibodies
– Immunoglobins
• IgG
• IgA
• IgM
• IgD
• IgE
• Intracellular pathogens activate T lymphocytes
• Helper T cells initiate immune response
Antibodies, continued
• Complement activates
– General inflammatory reaction
• Immune cells secrete cytokines
• Cytotoxic T lymphocytes
– Attack malignant cells
– Responsible for rejection of transplants
Lymphoid System
• Recovers proteins for vascular system
– Protects bloodstream from invading organism
• Lymph nodes
– Filter foreign products or antigens
– House and support lymphocytes and macrophages
• Spleen
– Filters blood
– White pulp and red pulp
Lymphoid System, continued
• Thymus gland
– Stimulates lymphopoiesis
• Bone marrow
– Produces, stores hematopoietic stem cells
• Lymphoid tissues
– Peyer’s patches
• Tonsils and adenoids
– Protect from inhaled or ingested foreign agents
Figure 14-4 The lymphoid system, showing the central organs of the thymus and bone marrow and the peripheral
organs, including the spleen, tonsils, lymph nodes, and Peyer’s patches.
Nonspecific Inflammatory
Response
• Barrier protection
• Bactericidal substances in body fluids
• Barrier breached  inflammation
– Nonspecific because same events occur
Immunizations
• Introduce antigen into body allowing immunity to develop
– Active immunity
– Passive immunity
• Types of vaccines
– Killed virus
– Toxoid
– Live virus
– Recombinant
– Conjugated
Immunizations, continued
• Responses to vaccines
– Local reaction
– Systemic reaction
– Local allergic reactions
– Life-threatening allergic reaction  anaphylaxis
Immunizations, continued
• Immunization schedule
– Specific ages and intervals
– Schedule updated annually
– Assess immunization status at every visit
• Contraindications
– Acute illness with high fever
– Reaction
– Treatments
– Pregnancy
Immunizations, continued
• Parental rights and informed consent
– Concerns and beliefs
– Disagree with regulation
– Low risk
– Adverse events
– Control susceptibility
– Better to get disease
• Inform parents
– Document refusal
Healthy People 2010
• Nationwide effort to eliminate serious preventable threats
– Eliminate
– Reduce
• Increase numbers of children protected
– Pediatric immunizations
Pediatric Differences
• Immune system development complex
• Multifactorial
– Differing amount of immunoglobulins in infants and children
– Normal values not achieved until 6–7 years
– Cell-mediated immunity achieves full function early
Normal Changes of Aging
• Immune function declines with aging
• External and internal factors
– Decrease in immune response
– Lowered resistance to infections
– Poor response to immunizations
– Autoantibodies more common
Alterations
• Altered immune system responses
– Hyperresponsiveness
• Allergies
– Impaired immune response
• AIDS
Physical Assessment
• Health history
– Review biographic data
– Family history
– Provide privacy
– Individualize terms used
Physical Examination
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General appearance
Vital signs
Inspect mucous membranes
Assess skin color, temperature, moisture
Inspect skin
Inspect and palpate lymph nodes
Assess musculoskeletal system
Check joint ROM
Diagnostic tests
• Enzyme
Immunoassay
• Immunoglogulins
• Polymerase chain
reaction
• Rapid HIV test
• Radioallergosorbent
test
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Skin reactions
Western blot test
Complete CBC test
Complement
Enzyme-linked
immunosorbent
assay
Collaboration
• Caring interventions
– Nutrition
– Exercise
– Sleep
– Stress reduction
• Pharmacologic therapy
– Restore immune function
Collaboration, continued
– Mild manifestations  supportive treatment
• NSAIDS
• Corticosteroids
– Prevention and prompt treatment of infection
• Antibiotic therapy
• Prophylaxis
• Immunizations
• IV immunoglobulin to provide protection
• Complementary therapies
Exemplar 14.2 Hypersensitivity
• Altered immune response to an antigen that results in harm
• Response may be bothersome or life threatening
• Classified by type of response, immediate or delayed, organ system, or
allergen
Pathophysiology and Etiology
• Type I (IgE-mediated) hypersensitivity
– Common hypersensitivity
• Triggered when allergen interacts with free IgE
• Allergens can be ingested in foods, injected, inhaled, absorbed
– Systemic response, such as anaphylaxis
– Localized response, such as asthma, more common
Figure 14-14 Type I (IgE-mediated) hypersensitivity response.
Pathophysiology and Etiology,
continued
• Type II (Cytotoxic) hypersensitivity
– IgG or IgM-type antibodies formed to a cell-bound antigen
– Antibodies bind with antigen
– May be stimulated by exogenous antigen
• Foreign tissue or cells
• Drug reaction
• Withdrawal of antigen stops hemolysis
Figure 14-15 Type II (cytotoxic) hypersensitivity response.
Pathophysiology and Etiology,
continued
• Type III (Immune complex-mediated) hypersensitivity
– Results from formation of IgG or IgM antibody-antigen immune
complexes in circulatory system
– Local
• Immune complex accumulates
– Systemic
• Fever urticaria, rash, arthralgias
Figure 14-16 Type III (immune complex–mediated) hypersensitivity response.
Pathophysiology and Etiology,
continued
• Type IV (delayed) hypersensitivity
– Cell-mediated responses
– Results from exaggerated interaction
– Contact dermatitis
– Latex allergy
• Can progress to type I reaction
• Common in clients with certain health conditions
– Measures to protect against latex allergy
– Latex in the hospital and home environment
Figure 14-17 Type IV (delayed) hypersensitivity response.
Pathophysiology and Etiology,
continued
• Etiology
– Estimated 50 million people in U.S. have some form of hypersensitivity
– Secondary immune response may decrease with age
• Risk factors
– Incidence and intensity increases with previous exposure
– Family member with allergy increases risk for child
Clinical Manifestations
• Range
– Mild hypersensitivity
– Moderate hypersensitive responses of skin
– Severe reactions
• Care for client
– Focus minimizing exposure to allergen
– History of exposure
– Type of response, onset, manifestations
Care for Client, continued
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Withdraw allergen immediately
Maintain airway, cardiac output
Manage bleeding, renal failure
Supportive care to relieve discomfort
Collaboration
• Recurrent moderate sever hypersensitivity
– Refer to specialist
• Children with severe hypersensitivity reactions
– Help parents design action plan for school
– Support groups
Diagnostic Tests
• Laboratory testing
– WBC with differential
– Radioallergosorbent test (RAST)
– Blood type and cross match
– Indirect Coombs’ test
– Direct Coombs’ test
– Immune complex assays
– Complement assay
Diagnostic Tests, continued
• Skin testing
– Used to determine causes of hypersensitivity reactions
– Allergens selected according to client’s history
– Epicutaneous testing done first
• Intradermal
• Prick test
• Patch test
• Food allergy test
Pharmacologic Therapies
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Based on severity of hypersensitivity reaction
Antihistamines
Commonly sodium
Corticosteroids
– Systemic
– Topical
• Immunotherapy
Pharmacologic Therapies, continued
• Epinephrine
– Immediate treatment for anaphylaxis
– Adrenergic agonist
– Subcutaneous injection
– Clients with history of anaphylaxis
• Epipen
• Amalizumab
– Inhibits type I hypersensitivity reactions
Clinical Therapies
• Airway management
– Endotracheal tube, emergency tracheostomy
– IV line
• Initiate fluid resuscitation with isotonic solution
• Plasmapheresis
– Plasma and glomerular damaging antibody-antigen complexes
removed
– RBCs returned to client with albumin, plasma
– Series
Clinical Therapies, continued
• Complementary therapies
– Clients with type I hypersensitivity
• Contact physician prior to using herbals, teas, aromatherapy
– Cultural therapies
• Asian Americans
• Native Americans
Nursing Process:
Assessment
• Health history
– Risk factors
– Hypersensitivities
– Reaction
– Type of treatment for reactions
– Allergy skin testing
– History of asthma, hay fever, dermatitis
• Physical assessment
Diagnosis
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Ineffective Airway Clearance
Decreased Cardiac Output
Risk for Injury
Impaired Spontaneous Ventilation
Risk for Shock
Plan
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Client will avoid known substances that provoke hypersensitivity response
Client will describe self-care to reduce symptoms of seasonal allergies
Client will describe proper self- administration of medications
Client participates in determining substances that cause hypersensitivity
Implementation:
Ineffective Airway Clearance
• Maintain patent airway
• Fowler’s, high-Fowler’s position
• Assess respiratory status, loc
– Anxiety, air hunger, possible obstruction
• Administer oxygen per nasal cannula
• Insert nasopharyngeal or oropharyngeal airway
• Administer subcu epinephrine as prescribed
Implementation:
Decreased Cardiac Output
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Monitor vital signs, LOC frequently
Insert one or more large bore IV catheter
Administer warmed IV solutions
Insert indwelling catheter, monitor output
Place tourniquet above site of injected venom
• Once breathing established, place client flat
with legs elevated
Implementation:
Risk for Injury
• Obtain and record thorough history
– Previous transfusions
– Any reactions
• Check for informed consent for blood, products
• Use two licensed health care professionals to check client identity, blood
type, Rh factor, cross match, expiration date
Implementation:
Risk for Injury, continued
• Take and record vital signs within 15 minutes
– Before initiating blood transfusion
• Acetaminophen and diphenhydramine are prescribed prior to beginning
transfusion
• Infuse blood into separate infusion site
• Use catheter of at least 20 gauge for infusion
Implementation:
Risk for Injury, continued
• Administer with normal saline to prime IV
• Administer 50mL blood during first 15 mins
• During transfusion monitor for
– Complaints of back, chest pain
– Temperature increase over 1.8°F
– Chills, tachycardia, tachypnea
– Wheezing, hypotension
– Hives, rashes
– Cyanosis
Implementation:
Risk for Injury, continued
• Stop transfusion immediately if reaction occurs
– No matter how mild
– Send blood and administration set to lab
– Fresh blood and urine samples from client
• If no adverse reaction occurs
• Administer over 2–4 hours
– Time frame important to limit risk of bacterial growth
Community-Based Care
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Teaching vital component of care
When and how to use anaphylaxis kit
When to seek medical attention
Use and adverse reactions of medications
Advantages of autologous blood transfusion
Community-Based Care, continued
• Prevention of immune complex reaction
• Skin care to prevent contact dermatitis
– Expose skin to air, sun as much as possible
– Avoid contact with people with infection
– Natural fibers
– Avoid extremes of heat and cold
Evaluation
• Client exhibits decreased symptoms
• Client demonstrates proper technique when administering medication
• Client provides accurate thorough information in journal