IMMUNITYIMMUNITYWeek 3Week 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• 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

• 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

– 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• 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• Ineffective Airway Clearance• Decreased Cardiac Output• Risk for Injury• Impaired Spontaneous Ventilation • Risk for Shock

Plan• 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

• 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• 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