Understanding the Immune System

• The immune system protects the body from foreign invaders and pathogens. It distinguishes between "self" and "non-self" antigens.
• Immune disorders arise from either an overactive or underactive immune response. These can manifest as hypersensitivity reactions, autoimmune diseases, or immunodeficiency disorders.

Components of the Immune System

• Innate Immunity: The first line of defense, providing immediate, non-specific protection.
  • Physical barriers: skin, mucous membranes
  • Chemical barriers: enzymes in tears and saliva, acidic environment of the stomach
  • Cellular defenses: natural killer cells, phagocytes (macrophages, neutrophils)
  • Inflammatory response: triggered by tissue damage or infection, leading to vasodilation and immune cell recruitment
• Adaptive Immunity: A specific immune response that develops over time, involving lymphocytes (T cells and B cells).
  • B cells: produce antibodies (immunoglobulins) that bind to specific antigens, marking them for destruction.
  • T cells:
    • Helper T cells (CD4+): coordinate the immune response by releasing cytokines.
    • Cytotoxic T cells (CD8+): directly kill infected or cancerous cells.

Types of Immune Responses

• Humoral Immunity: Mediated by antibodies produced by B cells, effective against extracellular pathogens.
• Cell-Mediated Immunity: Mediated by T cells, effective against intracellular pathogens, cancer cells, and foreign tissue.

Hypersensitivity Reactions

• Excessive or inappropriate immune responses that result in tissue damage.
• Type I (Immediate): IgE-mediated, triggered by allergens.
  • Examples: allergic rhinitis, asthma, anaphylaxis.
  • Nursing care: avoid allergens, administer antihistamines, corticosteroids, and epinephrine for anaphylaxis; teach patients about self-administration of epinephrine.
• Type II (Cytotoxic): IgG or IgM antibodies bind to cell surface antigens, leading to cell destruction.
  • Examples: hemolytic transfusion reactions, Goodpasture syndrome.
  • Nursing care: monitor for signs of hemolysis (e.g., fever, chills, back pain, dark urine); administer medications as prescribed (e.g., corticosteroids, immunosuppressants).
• Type III (Immune Complex): Antibody-antigen complexes deposit in tissues, leading to inflammation and damage.
  • Examples: systemic lupus erythematosus (SLE), rheumatoid arthritis.
  • Nursing care: manage inflammation and pain; administer medications as prescribed (e.g., NSAIDs, corticosteroids, immunosuppressants); monitor organ function.
• Type IV (Delayed): T cell-mediated, delayed response to an antigen.
  • Examples: contact dermatitis, tuberculin skin test.
  • Nursing care: avoid irritants; administer topical corticosteroids; educate patients about skin care.

Autoimmune Disorders

• The immune system attacks the body's own tissues.
• Loss of self-tolerance, where the immune system fails to recognize self-antigens.
• Examples:
  • Systemic Lupus Erythematosus (SLE): Chronic, systemic inflammatory disease affecting multiple organs.
    • Nursing care: monitor organ function; administer medications to manage inflammation and suppress the immune system; protect skin from sun exposure; provide emotional support.
  • Rheumatoid Arthritis (RA): Chronic inflammatory disorder primarily affecting the joints.
    • Nursing care: manage pain and inflammation; maintain joint function; administer medications as prescribed (e.g., NSAIDs, DMARDs, biologic agents); provide assistive devices.
  • Multiple Sclerosis (MS): Autoimmune disease affecting the brain and spinal cord.
    • Nursing care: manage symptoms (e.g., fatigue, muscle weakness, spasticity); promote mobility; administer medications to modify the disease course and manage symptoms; provide emotional support.
  • Type 1 Diabetes Mellitus: Autoimmune destruction of insulin-producing cells in the pancreas.
    • Nursing care: educate patients about insulin administration, blood glucose monitoring, diet, and exercise; monitor for complications (e.g., hypoglycemia, hyperglycemia); provide emotional support.

Immunodeficiency Disorders

• The immune system is weakened or absent, increasing susceptibility to infections.
• Primary Immunodeficiency: Genetic defects affecting immune cell development or function.
  • Severe Combined Immunodeficiency (SCID): Absence of both T and B cells.
    • Nursing care: prevent infection; administer prophylactic antibiotics and IVIG; prepare for hematopoietic stem cell transplantation.
• Secondary Immunodeficiency: Acquired as a result of infection, malnutrition, medications, or other factors.
  • Human Immunodeficiency Virus (HIV) infection leading to Acquired Immunodeficiency Syndrome (AIDS): HIV attacks CD4+ T cells, weakening the immune system.
    • Nursing care: monitor CD4+ count and viral load; administer antiretroviral therapy (ART) to suppress viral replication; prevent and treat opportunistic infections; provide emotional support and education about safe sex practices.
  • Immunosuppressive Medications: Used to prevent organ rejection after transplantation or to treat autoimmune diseases.
    • Nursing care: monitor for signs of infection; administer medications as prescribed; educate patients about the importance of medication adherence and avoiding exposure to infections.

Nursing Assessment of Patients with Immune Disorders

• Health History:
  • Allergies, previous infections, autoimmune diseases, immunodeficiency disorders, medications, family history.
• Physical Examination:
  • Assess for signs of infection (e.g., fever, redness, swelling, purulent drainage).
  • Evaluate skin for rashes, lesions, or signs of allergic reactions.
  • Palpate lymph nodes for enlargement.
  • Assess respiratory and cardiovascular systems for signs of complications.
• Diagnostic Tests:
  • Complete blood count (CBC) with differential: evaluates immune cell numbers and types.
  • Immunoglobulin levels: measures antibody levels (IgG, IgM, IgA, IgE).
  • T cell subsets: measures CD4+ and CD8+ T cell counts.
  • Allergy testing: identifies specific allergens.
  • Autoantibody testing: detects antibodies against the body's own tissues (e.g., ANA, rheumatoid factor).
  • HIV testing: detects HIV infection.

Nursing Interventions for Patients with Immune Disorders

• Preventing Infection:
  • Hand hygiene, aseptic technique for procedures, isolation precautions as needed (e.g., neutropenic precautions for patients with low neutrophil counts), avoid exposure to sick individuals, vaccinations.
• Managing Symptoms:
  • Medications to control inflammation, pain, and other symptoms; rest and energy conservation; nutritional support; emotional support and counseling.
• Patient Education:
  • Disease process, medications, potential complications, self-care strategies, importance of follow-up appointments, resources and support groups.

Medications Used in Immune Disorders

• Immunosuppressants: Suppress the immune system to prevent organ rejection or treat autoimmune diseases.
  • Examples: Cyclosporine, azathioprine, methotrexate.
  • Nursing considerations: Monitor for signs of infection, nephrotoxicity, hepatotoxicity, and bone marrow suppression; educate patients about the importance of medication adherence and avoiding exposure to infections.
• Corticosteroids: Reduce inflammation and suppress the immune system.
  • Examples: Prednisone, methylprednisolone.
  • Nursing considerations: Monitor for side effects (e.g., hyperglycemia, weight gain, mood changes, osteoporosis); educate patients about the importance of taking medications as prescribed and tapering the dose gradually.
• Antihistamines: Block histamine release, reducing allergic symptoms.
  • Examples: Diphenhydramine, loratadine, cetirizine.
  • Nursing considerations: Monitor for sedation, dry mouth, and other side effects; educate patients about avoiding activities that require alertness while taking sedating antihistamines.
• Epinephrine: Used to treat anaphylaxis.
  • Nursing considerations: Administer intramuscularly or subcutaneously; monitor for side effects (e.g., tachycardia, hypertension, anxiety); educate patients about self-administration of epinephrine and the importance of seeking immediate medical attention after use.
• Antiretroviral Therapy (ART): Used to suppress HIV replication.
  • Nursing considerations: Monitor for side effects; educate patients about the importance of medication adherence, safe sex practices, and regular monitoring of CD4+ count and viral load.
• Disease-Modifying Antirheumatic Drugs (DMARDs): Used to slow the progression of rheumatoid arthritis and other autoimmune diseases.
  • Examples: Methotrexate, sulfasalazine, hydroxychloroquine.
  • Nursing considerations: Monitor for side effects; educate patients about the importance of regular monitoring for liver and kidney function and blood counts.
• Biologic Agents: Target specific components of the immune system to reduce inflammation in autoimmune diseases.
  • Examples: Infliximab, adalimumab, etanercept.
  • Nursing considerations: Monitor for signs of infection and infusion reactions; educate patients about the importance of avoiding live vaccines and reporting any signs of infection.

Psychosocial Considerations

• Patients with immune disorders may experience anxiety, depression, and social isolation.
• Provide emotional support and counseling; encourage participation in support groups; address concerns about body image, sexuality, and relationships.

Geriatric Considerations

• Older adults are at increased risk for immune dysfunction due to age-related changes in the immune system.
• Monitor for signs of infection; provide vaccinations as recommended; educate patients about preventive measures to reduce the risk of infection.

Explore the human immune system, its components (innate and adaptive immunity), and its function in defending the body against pathogens. Learn about immune disorders resulting from an overactive or underactive immune response, such as hypersensitivity, autoimmune diseases and immunodeficiency.