💊Pharmacology for Nurses Unit 6 – Immune System and Inflammation Basics

Key Concepts and Terminology

• Innate immunity provides immediate, non-specific defense against pathogens and foreign substances
• Adaptive immunity develops over time, providing specific and long-lasting protection against specific antigens
• Antigens are substances that trigger an immune response (bacteria, viruses, allergens)
• Antibodies are proteins produced by B cells that neutralize or mark antigens for destruction
• Cytokines are signaling molecules that regulate immune responses and inflammation (interleukins, interferons, tumor necrosis factors)
  • Proinflammatory cytokines promote inflammation (IL-1, IL-6, TNF-α)
  • Anti-inflammatory cytokines suppress inflammation (IL-4, IL-10, TGF-β)
• Leukocytes are white blood cells involved in immune responses (neutrophils, lymphocytes, monocytes, eosinophils, basophils)
• Complement system consists of proteins that enhance the immune response and promote inflammation

Anatomy of the Immune System

• Lymphoid organs are tissues that produce, mature, and store lymphocytes
  • Primary lymphoid organs include the bone marrow and thymus
  • Secondary lymphoid organs include lymph nodes, spleen, and mucosa-associated lymphoid tissue (MALT)
• Lymphatic system transports lymph fluid, immune cells, and antigens throughout the body
• Bone marrow is the site of hematopoiesis, producing all blood cells, including immune cells
• Thymus is the site of T cell maturation and selection
• Lymph nodes filter lymph fluid and provide a site for antigen presentation and lymphocyte activation
• Spleen filters blood, removes aged or damaged blood cells, and stores platelets and immune cells
• MALT is found in mucosal surfaces (respiratory, gastrointestinal, urogenital tracts) and provides local immune protection

Types of Immune Responses

• Cell-mediated immunity involves T cells directly attacking infected or abnormal cells
  • Cytotoxic T cells (CD8+) destroy infected or cancerous cells
  • Helper T cells (CD4+) coordinate immune responses by secreting cytokines and activating other immune cells
  • Regulatory T cells (Tregs) suppress immune responses to prevent autoimmunity and excessive inflammation
• Humoral immunity involves B cells producing antibodies that neutralize or mark antigens for destruction
  • Plasma cells are differentiated B cells that secrete large amounts of antibodies
  • Memory B cells provide long-lasting immunity and rapid antibody production upon re-exposure to an antigen
• Innate immune responses are immediate and non-specific, involving physical and chemical barriers, phagocytic cells, and inflammation
  • Physical barriers include skin, mucous membranes, and cilia
  • Chemical barriers include enzymes (lysozyme), antimicrobial peptides (defensins), and acidic pH
  • Phagocytic cells (neutrophils, macrophages) engulf and destroy pathogens
• Adaptive immune responses are specific and develop over time, involving T cells and B cells
  • Antigen presentation by dendritic cells and macrophages activates T cells and B cells
  • Clonal expansion of activated lymphocytes produces large numbers of antigen-specific cells
  • Memory cells provide long-lasting immunity and rapid response upon re-exposure to an antigen

Inflammation Process and Mediators

• Inflammation is a protective response to tissue injury or infection, characterized by redness, swelling, heat, pain, and loss of function
• Acute inflammation is a short-term response that promotes healing and resolves within days to weeks
  • Vasodilation increases blood flow to the affected area, causing redness and heat
  • Increased vascular permeability allows fluid and immune cells to enter the tissue, causing swelling
  • Pain results from the release of prostaglandins and other inflammatory mediators
• Chronic inflammation is a prolonged response that can lead to tissue damage and contribute to various diseases (atherosclerosis, cancer, autoimmune disorders)
• Inflammatory mediators are substances that initiate, amplify, and regulate the inflammatory response
  • Histamine is released by mast cells and basophils, causing vasodilation and increased vascular permeability
  • Prostaglandins are lipid mediators that promote vasodilation, pain, and fever
  • Leukotrienes are lipid mediators that promote bronchoconstriction, increased vascular permeability, and leukocyte recruitment
  • Cytokines (IL-1, IL-6, TNF-α) promote the acute phase response, leukocyte activation, and fever
• Resolution of inflammation involves the clearance of inflammatory mediators, apoptosis of immune cells, and tissue repair
  • Lipoxins, resolvins, and protectins are lipid mediators that promote the resolution of inflammation
  • Anti-inflammatory cytokines (IL-4, IL-10, TGF-β) suppress immune responses and promote tissue repair

Common Inflammatory Disorders

• Rheumatoid arthritis is an autoimmune disorder characterized by chronic inflammation of the joints, leading to pain, stiffness, and deformity
• Inflammatory bowel diseases (Crohn's disease, ulcerative colitis) involve chronic inflammation of the gastrointestinal tract, causing abdominal pain, diarrhea, and weight loss
• Asthma is a chronic inflammatory disorder of the airways, characterized by bronchoconstriction, mucus production, and airway hyperresponsiveness
• Psoriasis is a chronic inflammatory skin disorder characterized by the formation of scaly, itchy, and painful plaques
• Allergic reactions involve an exaggerated immune response to harmless substances (allergens), leading to inflammation and symptoms such as itching, swelling, and difficulty breathing
  • Type I hypersensitivity reactions are mediated by IgE antibodies and mast cell degranulation (anaphylaxis, allergic rhinitis, asthma)
  • Type IV hypersensitivity reactions are mediated by T cells and delayed inflammation (contact dermatitis)
• Sepsis is a life-threatening condition caused by an overwhelming inflammatory response to infection, leading to organ dysfunction and shock

Pharmacological Interventions

• Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) enzymes, reducing the production of prostaglandins and inflammation
  • Examples include ibuprofen, naproxen, and celecoxib
  • Adverse effects may include gastrointestinal irritation, bleeding, and renal impairment
• Corticosteroids are potent anti-inflammatory drugs that suppress the immune response by inhibiting the production of cytokines and other inflammatory mediators
  • Examples include prednisone, methylprednisolone, and dexamethasone
  • Adverse effects may include immunosuppression, osteoporosis, and metabolic disturbances
• Disease-modifying antirheumatic drugs (DMARDs) are used to slow the progression of rheumatoid arthritis by suppressing the immune response
  • Examples include methotrexate, sulfasalazine, and hydroxychloroquine
  • Adverse effects may include hepatotoxicity, bone marrow suppression, and gastrointestinal disturbances
• Biologic agents are targeted therapies that inhibit specific inflammatory mediators or pathways
  • Examples include TNF-α inhibitors (etanercept, infliximab), IL-6 inhibitors (tocilizumab), and IL-1 inhibitors (anakinra)
  • Adverse effects may include increased risk of infections, injection site reactions, and rarely, malignancies
• Antihistamines block the effects of histamine, reducing symptoms of allergic reactions
  • Examples include diphenhydramine, loratadine, and cetirizine
  • Adverse effects may include sedation, dry mouth, and urinary retention
• Leukotriene modifiers (montelukast, zafirlukast) inhibit the effects of leukotrienes, reducing inflammation in asthma and allergic rhinitis

Nursing Considerations and Patient Education

• Assess patients for signs and symptoms of inflammation, such as redness, swelling, pain, and fever
• Monitor patients for adverse effects of anti-inflammatory medications, such as gastrointestinal irritation, bleeding, and immunosuppression
• Educate patients about the proper use and potential side effects of their medications
  • Encourage patients to take NSAIDs with food or milk to reduce gastrointestinal irritation
  • Advise patients to report any signs of infection, such as fever, chills, or persistent cough, when taking immunosuppressive medications
• Promote lifestyle modifications that may reduce inflammation and improve overall health
  • Encourage a balanced diet rich in fruits, vegetables, whole grains, and omega-3 fatty acids
  • Recommend regular exercise and stress management techniques
  • Advise patients to avoid smoking and limit alcohol consumption
• Provide emotional support and resources for patients with chronic inflammatory disorders
  • Refer patients to support groups or counseling services
  • Encourage patients to communicate openly with their healthcare team about their concerns and treatment goals
• Collaborate with other healthcare professionals, such as physicians, pharmacists, and physical therapists, to provide comprehensive care for patients with inflammatory disorders

Clinical Applications and Case Studies

• Case 1: A 45-year-old woman presents with joint pain, stiffness, and swelling in her hands and wrists. She is diagnosed with rheumatoid arthritis and started on methotrexate and low-dose prednisone.
  • Nursing considerations: Monitor for adverse effects of medications, provide patient education on proper medication use and lifestyle modifications, and assess for improvement in symptoms and quality of life.
• Case 2: A 28-year-old man with a history of asthma presents to the emergency department with shortness of breath, wheezing, and chest tightness. He is treated with nebulized albuterol and oral prednisone.
  • Nursing considerations: Assess for improvement in respiratory symptoms, monitor for adverse effects of medications, and provide patient education on proper inhaler technique and avoidance of asthma triggers.
• Case 3: A 60-year-old woman with a history of osteoarthritis presents with worsening knee pain and swelling. She is prescribed ibuprofen and referred to physical therapy.
  • Nursing considerations: Educate the patient on proper use of NSAIDs, encourage adherence to physical therapy exercises, and assess for improvement in pain and mobility.
• Case 4: A 35-year-old man with a history of psoriasis presents with new, painful, and scaly plaques on his elbows and knees. He is started on topical corticosteroids and referred to a dermatologist for further evaluation.
  • Nursing considerations: Provide patient education on proper application of topical medications, encourage adherence to treatment plan, and assess for improvement in skin lesions and quality of life.
• Case 5: A 50-year-old woman with a history of allergic rhinitis presents with sneezing, nasal congestion, and itchy eyes during the spring season. She is prescribed an intranasal corticosteroid and an oral antihistamine.
  • Nursing considerations: Educate the patient on proper use of intranasal sprays and oral medications, encourage avoidance of allergens, and assess for improvement in symptoms and quality of life.