Infection & Immunity Quiz

Infection & Immunity

• Infection is the invasion and multiplication of harmful microorganisms in the body, leading to illness.
• Infections can be acute (lasting days to weeks) or chronic (lasting longer than 12 weeks).
• Infections can be localized (limited to a specific area) or systemic (affecting the entire body).
• Sepsis is a life-threatening systemic infection with pathogens in the blood or tissues.
• An epidemic involves more cases of infection than usual, while a pandemic is a worldwide epidemic.
• Immunity is a physiological process that provides protection against diseases.
• Immunity is accomplished through the actions of the immune system.
• The immune system protects the body from foreign antigens (typically proteins).
• Microorganisms, like bacteria, viruses, parasites, and fungi, are common foreign antigens.

Student Learning Objectives

• Describe the general concept of immunity and infection.
• Explain the pathophysiological mechanisms and impact of altered immune responses and infection.
• Describe the principles, practices, and processes related to health assessment of impaired immune responses and infections using specific examples.
• Apply pharmacokinetics, pharmacodynamics, and pharmacotherapeutics of therapies targeting altered immune responses and infections, using specific examples (e.g. Penicillins, Cephalosporins).
• Apply the principles, practices, and processes of non-pharmacological therapies targeted to altered immune response and infection.
• Apply nursing process/clinical judgment to patients experiencing altered immune responses and infections.

Immunity

• Immunity involves the body's protection or defense from diseases.
• This function is achieved through the actions of the immune system.
• The immune system protects against foreign antigens.
• Common foreign antigens include microorganisms like bacteria, viruses, parasites, and fungi, as well as pollens, foods, venoms, vaccines, and transplanted tissue.

Immunity and Interrelated Concepts

• Immunity is influenced by factors such as nutrition, glucose regulation, stress and coping, inflammation, tissue integrity, and fatigue.
• Infection also has an impact on immunity.

Immunity Protection

• Innate immunity: protection present at birth.
• Acquired immunity: protection gained after birth through active or passive immunity.
• Natural active immunity develops through exposure to an antigen.
• Artificial active immunity results from immunizations.
• Artificial passive acquired immunity involves receiving specific immunoglobulins.
• Natural passive immunity is temporary, passing antibodies from a mother to a fetus.

Normal Physiological Process

• The body protects itself from microorganisms and harmful antigens.
• Damaged or dead tissues and cells are removed.
• The body identifies and removes abnormal cell growth and development.
• The immune response can be categorized as suppressed, optimal, or exaggerated.

Risk Factors for Changes in Immunity

• Older age
• Low socioeconomic status (SES)
• Non-immunized status
• Chronic illnesses
• Chronic drug therapies (e.g., corticosteroids, chemotherapy)
• Substance use disorders
• Unhealthy lifestyles
• Genetic risk for excessive or decreased immunity

Three Lines of Defense

• Skin surfaces form a barrier against infection.
• Mucous membranes, enzymes, and natural microbial flora.
• Complement proteins.
• Activities of T lymphocytes, granulocytes, and macrophages.
• Antibodies produced by T and B lymphocytes for acquired specific immunity.

Cells of the Immune Response

• White blood cells (leukocytes): Granulocytes (Neutrophils, Eosinophils, Basophils), Agranulocytes (Lymphocytes, Monocytes)
• B lymphocytes mature in the liver
• T lymphocytes develop in the thymus gland
• Natural killer cells assist in specific immune responses

Organs of the Immune System

• Lymphoid organs are scattered throughout the body (e.g., spleen, thymus gland, bone marrow, adenoids, tonsils, appendix).
• Lymphocytes form, grow, mature, and are released.
• Lymphatic system connects tissues and organs via blood.

Overview of Immune Response

• Production of various types of cells by the bone marrow like T cells and B cells.
• Cells are capable of reacting with and responding to antigens.
• Cells can produce antibodies.

Clonal Selection

• Cellular Immunity: T lymphocytes (CD8 cells) attack infected cells, fight intracellular viruses, tumors and fungi. Helper T cells (CD4 cells) regulate immune responses. Suppressor T cells prevent excessive responses.
• Humoral Immunity: B lymphocytes mature after exposure to an antigen forming plasma cells and memory cells to generate antibodies.

Normal Specific Immune Response

Illustrative diagram of cell interactions as specific components of the immune response (e.g., virus, macrophages, T-helper cells).

Phagocytes and the Complement System

• Phagocytes (e.g., macrophages, neutrophils) recognize and ingest foreign antibodies.
• They help with the proliferation and differentiation of T and B cells.

Antibody-Mediated Process

• Illustrative diagram outlining the steps in antibody production and interaction with antigens. Illustrative diagram of antibody production and subsequent interaction.

Antibodies (or Immunoglobulins)

• Nine types of antibodies: IgG, IgD, IgM, IgA, IgE
• These antibodies have different functions and locations in the body.

Primary and Secondary Immune Responses

Illustrative diagram showing the different antibody responses in primary and secondary immune responses to an antigen.

Age-Related Differences

• In utero-maternal alloantigen: immune cells immature, but provide innate immunity
• Infants and children: exposure to antigens and vaccinations
• Aging: declining immunity, increased risks of infections, reduced vaccine effectiveness, autoimmune conditions become more prevalent.

Suppressed Immune Response

• Primary Immunodeficiency (PI): The immune system is inadequately developed, and some components are missing.
• Secondary Immunodeficiency: Loss of immune function after treatment or illness (e.g., treatment for organ transplant, cancer).

Assessment (SLO #5)

• History: details about previous infections, allergies, treatments, etc.
• Clinical findings: physical examination for signs of infection.
• Diagnostic tests: to help discriminate between infections, and whether the response is local or systemic.
• Laboratory tests: e.g., CBC, biochemistry, blood/wound/urine cultures.
• Screening tests: e.g., CRP, ESR.
• Disease-specific testing: identify specific pathogens.

Hypersensitivity Reactions (SLO #4)

• Four types of hypersensitivity reactions: Type I (allergic), Type II (tissue-specific), Type III (immune complex), and Type IV (cell-mediated hypersensitivity).
• Each type has unique characteristics and potential outcomes.

Hypersensitivity Type I

• Illustrative diagram showing the cascade of events from allergen exposure to the response of chemical mediators from mast cells.
• Allergic reactions can range from mild to severe anaphylactic shock.

Altered Immune Response

Different body systems that can be affected with abnormal immune responses are illustrated.

Allergy Assessment (SLO #5)

• History: past allergic reactions
• Allergy testing: skin prick tests, blood tests (IgE levels)
• Skin test: identify allergen-specific responses

Management (SLO #6)

• Primary prevention: vaccination, modifying risk factors.
• Secondary prevention: screening for infections.
• Treating problems: administering antimicrobials (antibiotics, antivirals, antifungals, antiparasitics).
• Immunosuppression (e.g., corticosteroids, NSAIDs) if necessary.
• Easy-to-read instructions, and easy-grip body for epinephrine auto-injectors (e.g. EpiPen).

Meet Mr. Hayes (Case study)

• A 50-year-old male undergoing gallbladder removal surgery.
• Complains of abdominal pain, receives morphine.
• Develops urticaria and angioedema (swelling of the lips).
• States a history of receiving morphine.
• Develops severe hypersensitivity reaction requiring emergency treatment as a result of the interaction between previous exposure to an antigen and the current administration of morphine.
• The case demonstrates acute allergic response to a drug.
• Further diagnostics and treatment are needed.

Management of Exaggerated Immune Response (Anaphylaxis)

• Support airway, breathing and circulation.
• Administer epinephrine, bronchodilators (e.g., albuterol).
• Provide circulatory support to maintain blood pressure.
• Treat underlying conditions via immunosuppression with corticosteroid therapy or NSAIDs

Mr. Hayes (follow-up)

• Mr. Hayes stabilizes, and morphine is discontinued by the physician.

Vaccines

• Vaccines are preventative measures that improve the immune response to infectious agents.
• Dosage, number of doses and timing are important considerations for vaccine administration.
• Common vaccines include those for diphtheria, tetanus, pertussis, polio, measles, mumps, rubella, varicella, hepatitis B, pneumonia, etc.
• Recommendations for vaccination schedules for various age groups may be found from governmental health organizations.

Vaccination

• Antigens trigger an immune response, so the body reacts more effectively next time to that triggering antigen.
• Effective vaccinations may require booster/follow-up doses.
• Bacterial and viral vaccines can be categorized into inactivated, killed, or live attenuated type.
• The type of vaccine used can influence the immune response it produces and the longevity of the protection.

Infections (SLO #2)

• Infection is the invasion and multiplication of harmful microorganisms.
• Different types of infections (bacterial, viral, fungal, parasitic) exist.
• Infections can be localized or systemic, and have a variety of transmission methods.

Chain of Infection

• The components of this process include an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host.

Methods of Transmission

• Contact transmission: direct or indirect physical contact.
• Droplet transmission: transmission via large respiratory droplets.
• Airborne transmission: transmission of pathogens through smaller, airborne particles.

Infection Control and Prevention

• Hand hygiene measures are essential to prevent infection transmission.
• Standard precautions and transmission-based precautions are used in healthcare settings to prevent infectious agents from spreading.
• Isolation precautions may be implemented for patients with certain infectious conditions.

4 Moments of Hand Hygiene

• Specific times for performing hand hygiene.

Stages of Infectious Diseases

• Incubation, Prodromal, Illness, Convalescence
• Incubation period precedes the appearance of the symptoms
• Prodromal period precedes the period of illness.
• Illness period is marked by the presence of specific symptoms characteristic of the infection.
• Convalescent stage is the recovery from the disease and return to homeostasis without symptoms.

Risk Factors for Infection

• Factors like compromised immune systems, age, malnutrition, underlying health conditions, and lifestyle choices can increase risk for infections.
• Pathogens have various ways to cause infection including bypassing body’s defenses, and having high reproductive speed.
• Opportunistic pathogens take advantage of a weakened immune system for successful infection.

Clinical Manifestations of Infection

• Local signs: redness, pain, swelling, exudates (pus).
• Systemic signs: fever, fatigue, headache, anorexia, nausea, malaise, muscle pain.

Consequences of Infection

• Severe, poorly responsive infections can lead to septic shock and multi-organ dysfunction syndrome (MODS).
• Complications like various symptoms, such as hypotension, tachycardia, tachypnea, oliguria, anuria, hypoxia, hypercapnia, potentially leading to coma and death, may also occur.

Assessment (SLO #5)

• History taking is essential to understand various symptoms, and possible triggers.
• Physical examination for local signs of infection and general systemic symptoms.
• Diagnostic testing to ascertain probable pathogens.
• Laboratory and/or imaging tests to confirm the diagnosis.

Clinical Management

• Methods of managing infections like use of antimicrobials, primary and secondary prevention strategies.
• Control measures that limit exposure and spread of infection should be practiced in healthcare settings.

Lab Values for Infection

• Biochemistry (e.g., electrolytes, creatinine).
• Complete blood counts for WBC counts and differential (e.g., neutrophils, lymphocytes, eosinophils).
• Culture and sensitivity tests to identify the specific pathogen and its sensitivities to drugs.

Growing Bacteria

• Bacteria grow under controlled conditions.

Collaborative Interventions

• Antimicrobial drug therapy, fluids and electrolytes, rest, nutrition, fever management (e.g., antipyretics).

Anti-Infective Therapy (SLO #6)

• Treatment of various infections via antibiotics, antivirals, antifungals, and antiparasitics.
• These medications are used to combat pathogens specific to their origin.

Anti-infective agents

• Antibiotics treat bacterial infections.
• Antivirals treat viral infections.
• Antifungals treat fungal infections.
• Antiparasitics treat parasitic infections.

Classification of Antibiotic Drugs

• Classification by susceptible organisms (narrow or broad)
• Classification by mechanism of action (bacteriostatic or bactericidal).

How Antibiotics Work

• Bacteriostatic antibiotics slow the multiplication of bacteria.
• Bactericidal antibiotics kill bacteria.

Suspected Infection, Nurse/Physician Orders, Samples

• Orders, samples, and testing procedures when infection is suspected.

Gram Stain

• Gram-positive bacteria stain a certain color, while gram-negative bacteria stain a different color.

Antibiotics

• Antibiotics target the differences between bacteria and human cells, to be selectively toxic on bacteria.
• Effective antibiotics must be taken at the appropriate dose and for the appropriate duration.
• The use of antibiotics can result in side effects and/or complications when used improperly.
• Adverse drug effects may include allergic responses, liver and kidney damage.

Administering Antibiotic Therapy (nurse considerations)

• Identifying the bacteria/type of microorganism impacted by the administered treatment,
• Mechanism of action of the administered antibiotic
• Spectrum of activity of the administered antibiotic (narrow, broad),
• Adverse effects of the administered antibiotic
• Nursing considerations for patient teaching and monitoring.

Penicillins, Cephalosporins, Macrolides

• Properties and characteristics that differentiate these groups of antibiotics
• Their mechanism of action, spectrum, interactions, and common side effects.

Aminoglycosides, Sulfonamides, Tetracyclines, Fluoroquinolones

• MOA, spectrum, possible side effects, and situations where these antibiotics are used.
• The categories of drugs, properties, potential toxicity, and relevant nursing considerations.

Antibiotic Resistant Bacteria

• Resistance is when bacteria evolve to survive in the presence of antibiotics.
• Factors for resistance evolution include that antibiotics are taken improperly or are present in excessive doses.
• Bacteria may develop resistance by altering the structure of drug target molecules or by inactivating the drug.

Resistance-Selection

• Selection and survival of resistant strains in the presence of excessive antibiotic use.
• Infections that develop in hospitals (nosocomial infections) are often resistant to antibiotics owing to extensive antibiotic use within healthcare settings.

Suppressed Immune System Exemplar: MRSA

• MrSA as a case example of a bacterial infection that can be problematic if the immune system is weakened.
• Exemplar of a condition in which, the patient may be prone to infection.

Mrs. A (Case Study, continued)

• Provides patient vital signs and clinical characteristics when first evaluating.
• Outlines treatment protocol, results of clinical tests, resulting diagnosis, treatment, and outcomes.

Summary (review)

• Immunity is a diverse system of defense mechanisms against pathogens.
• Antibiotic therapy can be quite helpful to treat infections caused by various invading bacteria, however, this approach can lead to antibiotic resistant strains.
• Patient health outcomes are related to factors such as the severity of infection, patient immune response, and treatment.