infection

Infection Overview

• The body’s immune response can be overpowered by infections, leading to the infectious process and various symptoms.

Types of Infections

Classification

• Infections can be classified based on duration and location.

  • Acute Infections: Short-term infections that usually resolve in days or weeks.

    • Examples:

      • Urinary Tract Infection (UTI): Mild cases typically resolve within two weeks post-treatment.

      • Upper Respiratory Infection: Lasts about 7-10 days, typically viral.

  • Chronic Infections: Long-term infections lasting longer than twelve weeks; some may be incurable.

    • Examples:

      • HIV: Can become undetectable with treatment, complicating the definition of 'curable.'

      • Herpes Simplex Virus (HSV): Requires long-term management with medication.

      • Tuberculosis: A chronic infectious disease requiring long-term management.

Infection Location Classification

Localized Infections

• Defined as affecting a specific body area.

  • Examples:

    • Wound infection: Limited to the infected area.

    • Cellulitis: A bacterial skin infection.

    • Sinus infection: Limited to the sinus cavities.

    • Tooth infection: Localized around the tooth.

Disseminated Infections

• These infections spread from the initial site to other parts of the body.

  • Examples:

    • Chickenpox: A viral infection that can spread.

    • Tinea (ringworm): A fungal infection that spreads on the body.

    • UTI: Can start localized in the bladder but spread to the kidneys, causing pyelonephritis.

Systemic Infections

• Affect the entire body; can lead to severe conditions like sepsis.

Epidemic vs. Pandemic

• Epidemic: An increase in cases of infectious diseases beyond what is expected.

  • Examples: Measles outbreaks in specific regions.

• Pandemic: An epidemic that occurs worldwide, such as COVID-19.

Categories of Infections

• Bacterial Infections: One-celled organisms without a nucleus.

• Viral Infections: Pathogens comprised of nucleic acid within a protein shell.

• Fungal Infections: Organisms belonging to the fungal kingdom (e.g., Candida and molds).

• Parasitic Infections: Spread through vectors and contaminated environments.

Healthcare-Associated Infections

• Common infections acquired in healthcare settings include:

  • MRSA (Methicillin-resistant Staphylococcus aureus)

  • C. difficile (C. diff)

  • Pneumonia

  • VRE (Vancomycin-resistant Enterococcus)

  • Catheter-associated urinary tract infections (UTIs).

Components Needed for Infection

1. Pathogen: The infectious agent.

2. Host: The individual affected; e.g., humans in the case of Staphylococcus aureus.

3. Reservoir: Where pathogens reside; staph can live on skin or surfaces.

4. Portal of Exit: Route for pathogens to exit the reservoir (e.g., skin, saliva).

5. Mode of Transmission: Routes through which pathogens spread (e.g., direct contact, airborne).

6. Portal of Entry: Entry point for pathogens into a new host (e.g., through breaks in the skin or mucous membranes).

Immune Response During Infection

• Key immune cells respond to infections:

  • B Lymphocytes: Produce antibodies and memory cells for future exposure.

  • T Lymphocytes: Attack pathogens and stimulate macrophages to engulf bacteria.

  • Neutrophil Increase: Occurs as the body combats infections, indicating an active immune response.

Risk Factors for Infection

• Infants: Have immature immune systems, increasing infection risk.

• Elderly: Also at higher risk due to declining immune functions.

• Immunocompromised: Individuals with diseases like lupus or diabetes.

• Environment: Unsanitary conditions and overcrowding increase infection risk.

Management of Infections

• Assessment: Includes taking a detailed history and identifying symptoms.

  • Symptoms include pain, swelling, redness, and fever.

  • Review of any recent exposure to infected individuals.

• Diagnostics: Blood work, urine tests, and identifying white blood cell counts, particularly neutrophils and bands.

  • Elevated bands indicate acute infection presence.

• Treatment: Base treatment on infection type.

  • Bacterial Infections: Antibiotics, often starting with broad-spectrum options.

  • Viral Infections: Antiviral medications, e.g., Tamiflu for influenza.

  • Fungal Infections: Antifungals.

Preventive Measures

• Primary Prevention: Vaccinations (e.g., flu vaccine) and hand hygiene.

• Secondary Prevention: Regular screenings for infections.

• Tertiary Prevention: Treatment of existing infections and education on adherence to medication.

Patient Education for Infections

• Complete prescribed treatment courses, even if symptoms improve.

• Be aware of side effects of medications, such as nausea or changes in urine color.

• Teach about prevention of reinfection and the importance of hydration and nutrition.

Interrelated Concepts

• Immunity: Strong immunity prevents infections and is crucial in recovery.

• Nutrition: Proper nutrition supports immune function; malnutrition increases infection risk.

• Stress: High stress can weaken the immune system, increasing vulnerability to infections.