Infection Concepts for Nursing Practice

Concept 24: Infection

Lesson Overview

  • Define and describe the concept of infection.
  • Notice the risk factors for infection.
  • Recognize when an individual has an infection.
  • Provide appropriate nursing and collaborative interventions to eliminate infection.

Definitions

  • Infection: Defined as the invasion and multiplication of microorganisms in body tissues that may be unapparent. It can result from local cellular injury caused by:
      - Competitive metabolism
      - Toxins
      - Intracellular replication
      - Antigen-antibody response

Descriptors of Infection

  • Location: Types include:
      - Localized infection
      - Disseminated infection
      - Systemic infection
  • Duration: Types include:
      - Acute infection (lasts a few days or weeks)
      - Chronic infection (typically lasts longer than 12 weeks, may be incurable)
  • Source: Types include:
      - Hospital-acquired/health care-associated infection
      - Community-acquired infection
  • Source: Types include:
      - Primary infection
      - Secondary infection

Types of Infection

  • Localized infection: Confined to a specific body area.
  • Disseminated infection: Spread from an initial site to other parts of the body.
  • Systemic infection: Affects the body as a whole, spreads throughout the body.
  • Sepsis: A type of systemic infection characterized by the presence of pathogens in the blood or tissues.

Epidemic and Pandemic

  • Epidemic: A situation where the number of cases of an infectious disease exceeds what is normal for a population or geographic area (e.g., spread of smallpox or measles).
  • Pandemic: A worldwide epidemic of a disease (e.g., COVID-19).

Scope of Infection

  • Categorized based on:
      - Mode of transmission
      - Trajectory of illnesses
      - Body systems affected
  • Breakdown by pathogen/causative microorganism:
      - Bacterial infections: Dependent on type and area of body invaded (e.g., MRSA, E.Coli).
      - Viral infections: Disrupt normal host cellular functions; destruction of the virus by the immune system can also harm the host cell (e.g., HIV).
      - Fungal infections: Generally harmless in healthy individuals but can be fatal in immunocompromised cases (e.g., candidiasis).
      - Protozoa or parasitic infections: Often spread via the fecal-oral route from contaminated sources (e.g., malaria).
      - Other infections: An initial infection can lead to secondary infections as new pathogens are introduced.

Normal Physiological Process

  • Epidemiology: Critical for studying infections as it involves understanding how diseases spread in populations and how to control them.
  • Factors in infection:
      - Virulence: The severity or harmfulness of a pathogen.
      - Transmission: How the infection spreads.
      - Host susceptibility: Factors making hosts more vulnerable to infection.
      - Communicability and symptoms: How easily an infection spreads and its clinical manifestations.
      - Dormant phase: The potential for pathogens to remain inactive.
Iceberg Theory
  • Postulates that there are three levels of infection:
      1. Majority carry an infection asymptomatically (underwater part of the iceberg).
      2. Smaller group shows less severe symptoms.
      3. A small proportion exhibits classical symptoms (tip of the iceberg).

Infection Process

  • Pathogen invasion: Initial entry of pathogens.
  • Susceptible host: An individual unable to effectively combat the pathogen.
  • Reservoir: Locations where pathogens live and multiply (e.g., contaminated objects, stagnant water).
  • Portal of exit: Routes for pathogens to leave the reservoir (e.g., urine, feces, saliva, blood).
  • Mode of transmission: Lifeway through which the infection is spread (e.g., direct contact, airborne).
  • Portal of entry: Routes through which pathogens enter a susceptible host (e.g., skin breaks, gastrointestinal tract).

Age-Related Normal Differences

  • Pregnant women and young children may show increased susceptibility due to immature immune systems.
  • Elderly individuals often have a muted inflammatory response and may present with atypical symptoms.

Variations and Context

  • Infections can vary based on:
      - Severity
      - Location
      - Host response to treatment
      - Potential for debilitating consequences (e.g., mild infections vs. life-threatening conditions).

Consequences of Untreated Infection

  • If unresponsive, compensatory actions by the host will fail, potentially leading to death.
  • Potential outcomes:
      - Vascular, renal, and nervous system compensation.
      - Development of septic shock syndrome or multi-organ dysfunction syndrome with symptoms including:
        - Hypotension
        - Tachycardia
        - Tachypnea
        - Oliguria or anuria
        - Hypoxia
        - Hyperpnea
        - Seizures or coma.

Populations at Risk

  • Infections may affect all demographics; however, some groups are at greater risk:
      - Very young: with immature immune systems.
      - Poor/uninsured individuals: lacking access to preventive healthcare.
      - Residents in areas where infections are prevalent: limited access to treatment resources.

Individual Risk Factors

  • Immunodeficiency: Factors include primary immunodeficiencies, malnutrition, chronic diseases, psychological stress, immunosuppressive medications, and cancer treatment.
  • Chronic disease: Conditions like diabetes or cancer weaken the immune response, increasing vulnerability to infections.
  • Environmental conditions: Unsafe sanitary conditions heighten risk; factors include clean water availability and proper food preparation.

Assessment

  • History: Recognizing risk factors for infection, they include:
      - Recent treatments (cancer/surgery).
      - Travel history to areas with prevalent infections.
      - Exposure to large gatherings facilitating infectious pathogen transmission.
  • Examination findings: Assess for signs of infection, including:
      - Pain, swelling, redness
      - Generalized stress, fatigue, malaise.

Diagnostic Tests (1 of 2)

  • Laboratory tests:
      - Complete blood count (CBC): Critical for evaluating infection; elevated levels of specific white blood cells indicate infection.
      - Culture and sensitivity (C&S): Identifies pathogens and determines effective antimicrobial treatments.
  • Other laboratory tests:
      - C-reactive protein (CRP): Indicates inflammation.
      - Erythrocyte sedimentation rate (ESR): Measures inflammatory activity.
      - Serological tests: Detect specific antibodies or viruses.

Diagnostic Tests (2 of 2)

  • Radiographic studies:
      - Types include X-ray, MRI, CT, PET, and indium scans.
      - Useful for identifying infection and inflammation.

Clinical Management: Primary Prevention

  • Immunizations: Important for preventing infections; follow CDC-recommended schedules.
  • Hand hygiene: Essential to prevent the spread of infection; wash hands thoroughly (20 seconds) or use alcohol-based rubs (15 seconds).
  • Personal hygiene, food hygiene, and patient care hygiene are also critical components.

Clinical Management: Secondary Prevention (Screening)

  • Less effective at controlling infections but can enable earlier identification for treatment.
  • Common screenings include:
      - Sexually transmitted infections (STIs) in high-risk groups (e.g., pap smears).
      - Tuberculosis testing in high-risk populations.

Collaborative Interventions

  • Goal is to:
      - Eradicate infection,
      - Prevent secondary infections,
      - Limit bodily damage.
  • Antimicrobials: Prophylactic treatment using appropriate antibiotics, antivirals, and antifungals determined by laboratory testing.
  • Nutrition and fluids: Critical for maintaining hydration and supporting recovery during infections.
  • Disinfection: Maintenance of a clean physical environment to interrupt transmission.

Interrelated Concepts

  • Immunity: First line of defense against infections.
  • Inflammation: Symptoms of infection often overlap with inflammatory responses (e.g., redness, swelling).
  • Tissue integrity: Key to preventing infections; intact skin forms natural barriers to pathogens.
  • Stress and coping: Stress decreases the immune response, increasing vulnerability to infections and complications.
  • Nutrition: Essential for supporting immune responses and recuperation from infections.

Featured Exemplars

  • Pneumonia: Lung infection that can range from mild to severe. Symptoms include:
      - Chest tightness, shortness of breath, cough, fever.
      - Treated with antibiotics and antiviral drugs.
  • Conjunctivitis (Pink Eye): Symptoms include redness, swelling, and discharge from the eye.
  • Otitis Media: Divided into three types:
      - Acute Otitis Media (AOM): Painful, with pus and fever.
      - Otitis Media with Effusion (OME): Fluid buildup without symptoms.
      - Swimmer's Ear: Infection of the outer ear canal.
  • Hepatitis: Inflammation of the liver; can cause severe symptoms and requires treatment.
      - Causative agents: HAV, HBV, HCV.
  • Human Papillomavirus (HPV): Most common STI; can lead to cancer and is used for cervical cancer screening.

Questions and Answers

  • Question 1: What is primarily responsible for protecting the body in the blood?
      - Answer: Leukocytes. Rationale: They play a critical role in the immune response.
  • Question 2: Pathogens with nucleic acid within a protein shell that require a host for replication are?
      - Answer: Viruses. Rationale: They block host protein synthesis for replication.
  • Question 3: What is one of the most critical components for preventing infection?
      - Answer: Following proper hand hygiene.
      - Rationale: It is indispensable for infection prevention according to CDC guidelines.