Transcript 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 • • • • • • • • 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