HIV

INFECTION AND HUMAN IMMUNODEFICIENCY VIRUS INFECTION

INFECTIONS

  • Types of Infections:
    • Bacteria
    • Viruses
    • Fungi
    • Protozoa
    • Prions

INFECTIONS: BACTERIA

  • Normal Flora:
    • E. Coli is located in the large intestine.
  • Probiotics:
    • Beneficial bacteria that help in maintaining gut flora.
  • Damage Mechanisms:
    1. Bacteria can damage cells by growing inside them (e.g., Tuberculosis (TB)).
    2. They can secrete toxins that directly damage cells (e.g., Staphylococcus aureus).
  • Bacterial Classification Based on Shape:
    • Cocci: Round (e.g., Streptococcus & Staphylococcus)
    • Bacilli: Rod-shaped (e.g., TB)
    • Vibro: Curved rods (e.g., Cholera)
    • Spirochetes: Spiral-shaped (e.g., Syphilis)
  • Refer to Table 15.1: Disease Causing Bacteria

INFECTIONS: VIRUSES

  • Characteristics of Viruses:
    • Viruses are NOT cells; they are simple infectious particles that contain RNA or DNA and a protein envelope.
    • They can only reproduce inside the cells of a living organism.

INFECTIONS: FUNGI

  • Overview:
    • Fungi are similar to plants but lack chlorophyll.
    • Typically localized but can become systemic in immunocompromised individuals.
  • Common Fungal Infections:
    • Tinea Pedis (Athlete’s Foot)
    • Tinea Corporis (Ringworm)
    • Overgrowth of Candida albicans leads to conditions known as Candidiasis, which can occur in the mouth (thrush), esophagus, intestines, and vagina.

INFECTIONS: PROTOZOA

  • Description:
    • Infectious particles contain abnormally shaped proteins.
  • Diseases Caused:
    • Group of illnesses called transmissible spongiform encephalopathies (TSEs).
    • Examples include Creutzfeldt-Jakob disease and Bovine spongiform encephalopathy (Mad Cow Disease).

INFECTIONS: PRIONS

  • Definition:
    • Prions are infectious particles and single-cell, animal-like organisms that live in soil and bodies of water.
  • Diseases Caused:
    • Dysentery
    • Giardiasis
    • Malaria

EMERGING INFECTIONS

  • Definition:
    • Emerging infections are infectious diseases that have recently increased in incidence or threaten to increase in the immediate future.
  • Sources:
    • Can originate from animal populations (e.g., Severe Acute Respiratory Syndrome, West Nile Virus)
    • Additionally, organisms developing resistance to antibiotics contribute to this category.

REEMERGING INFECTIONS

  • Definition:
    • Reemerging diseases that were near eradication.
    • Typically include vaccine-preventable infections.
  • Examples:
    • Measles
    • Pertussis

ANTIBIOTIC RESISTANT ORGANISMS

  • Mechanisms of Resistance:
    • Pathogenic organisms adapt over time.
    • They have evolved genetic and biochemical mechanisms to defend against antimicrobials.
    • Biochemical enzymes can destroy or inactivate antibiotics, and drug target sites are altered so antibiotics cannot bind or enter the bacteria.
  • Consequences:
    • If the antibiotic cannot enter the cell, it cannot kill the bacteria.
  • Refer to Table 15.5: Detailed examination of antibiotics and resistance.

COMMON ANTIBIOTIC-RESISTANT ORGANISMS & TREATMENT

  • Bacteria Resistance Comparison:
    • Staphylococcus aureus:
    • Resistant to Methicillin
    • Preferred Treatment: Vancomycin
    • Enterococcus faecalis & Enterococcus faecium:
    • Resistant to Vancomycin, Streptomycin
    • Preferred Treatments: Gentamicin, Daptomycin (Cubicin), Linezolid (Zyvox)
    • Streptococcus pneumoniae:
    • Resistant to Penicillin G
    • Preferred Treatments: Ceftriaxone (Rocephin), Cefotaxime (Claforan)
    • Klebsiella pneumoniae:
    • Resistant to Carbapenems (Imipenem, Meropenem)
    • Preferred Treatments: Ceftazidime and Avibactam (Avycaz)

CONTRIBUTION TO ANTIBIOTIC RESISTANCE

  • Healthcare Provider Contributions:
    • May contribute through over-prescription or incorrect usage of antibiotics.
  • Patient Contributions:
    • Lack of adherence to dosage guidelines and the complete course of treatment.
  • Patient & Caregiver Education Tables:
    • Refer to Tables 15-7 & 15.9 for recommended educational materials.

TYPES OF ISOLATION PRECAUTIONS

  • Standard Precautions:
    • Used for all patients, regardless of diagnosis or infection status.
    • Includes handwashing and the use of appropriate personal protective equipment (PPE).
  • Transmission-Based Precautions:
    1. Airborne Precautions:
    • For infections spread by small particles in the air (e.g., Varicella, Measles, TB).
    1. Droplet Precautions:
    • For infections spread by large droplets (e.g., Influenza, Bacterial Meningitis).
    1. Contact Precautions:
    • For infections spread through skin-to-skin contact (e.g., C. difficile, MRSA, VRE).

DRUGS USED TO TREAT INFECTIONS

  • Selection Criteria:
    • The selection of drugs for treating infections considers the type of infection, pathogen involved, and patient factors.

INFECTIONS IN THE AGING ADULT

  • Higher Rates of HAIs:
    • Hospital-acquired infections (HAIs) occur two or three times more often in older patients than in younger patients.
  • Common UTIs:
    • Urinary tract infections (UTIs) are more prevalent in older adults, especially within long-term care facilities.
  • Risk Factors:
    • The presence of indwelling catheters increases the risk of infections.
  • Atypical Symptoms:
    • Older adults can present with cognitive and behavioral changes as indicators of infection rather than classic symptoms like fever, pain, or lab alterations.
    • Important Note: Do not solely rely on the presence of fever to indicate infection, as many elderly individuals display lower core body temperatures and diminished immune responses.

HUMAN IMMUNODEFICIENCY VIRUS INFECTION

  • Epidemiology:
    • More than one million people in the U.S. are living with HIV.
    • Approximately 37,600 new infections occur annually.
    • Death rates have been decreasing due to advancements in treatment.

HIV INCIDENCE STATISTICS

  • As of 2019, newly reported HIV infections reduced by 8% from 2015 to 2019.
  • Total Number of HIV Diagnoses in 2019:
    • 36,801 diagnoses, with 87% of the estimated 1.2 million people with HIV in the U.S. aware of their status.
  • Regional Distribution of Diagnoses:
    • (Percentage breakdown by region available in the original document).

TRANSMISSION OF HIV

  • Body Fluids:
    • HIV is transmitted through body fluids: blood, semen, vaginal secretions, and breast milk.
    • The virus can be transmitted a few days after infection and continues for life.
  • Modes of Transmission:
    • Not transmitted through casual contact.
    • Unprotected Sex: Most common mode of transmission.
    • Blood Products: Transmission from exposure to infected blood (1%).
    • Perinatal Transmission: During pregnancy (25% risk), delivery, or breastfeeding.
    • Risk can be reduced to <2% if the HIV-positive mother is treated with Antiretroviral Therapy (ART).

PATHOPHYSIOLOGY OF HIV

  • Type of Virus:
    • HIV is an RNA virus, specifically a retrovirus, which replicates backward (RNA to DNA).
  • Replication and Targeting:
    • HIV cannot replicate without a host, targeting CD4 T-cells.
    • Triggers reverse transcriptase for conversion from RNA to DNA.
  • CD4 Count and Immune Function:
    • Normal CD4 count is between 800-1200 cells/μl.
    • > 500 cells/μl: minimal immune effects.
    • < 500 cells/μl: immune impairment.
    • < 200 cells/μl: risk for opportunistic diseases.

ACUTE HIV INFECTION

  • Viral Load:
    • Characterized by a high viral load during the initial phase.
  • CD4 T-cell Response:
    • CD4 counts initially fall but return to baseline within 2-4 weeks post-infection.
  • Symptoms:
    • Mimic mononucleosis: fever, swollen lymph nodes, sore throat, headache, malaise, nausea, muscle joint pain, diarrhea, diffuse rash.

CHRONIC HIV PHASES

  • Asymptomatic Infection:
    • Includes an interval of approximately 10 years between HIV and AIDS.
    • Typically asymptomatic with limited signs of infection; individuals may be unaware they are infected and can still transmit the virus.
  • Symptomatic Infection:
    • Manifestations appear as the CD4 T-cell count drops below 200 cells/μl.
    • HIV progresses to an active stage with symptoms like persistent fever, night sweats, chronic diarrhea, recurrent headaches, and severe fatigue.
  • Common Infections During Symptomatic Stage:
    • CD4+ T cells drop leading to opportunistic infections such as shingles (varicella-zoster virus), oral & genital herpes, Kaposi sarcoma, oral hairy leukoplakia (Epstein-Barr virus), Candida overgrowth, thrush, and vaginal yeast infections.

ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)

  • Criteria for Diagnosis:
    • An individual with HIV is diagnosed with AIDS if they meet any of the following:
    1. CD4+ T-cell count drops below 200 cells/μl.
    2. Development of one of the following opportunistic infections:
      • Fungal
      • Protozoal
      • Bacterial
      • Viral
    3. Development of one of the following opportunistic cancers:
      • Invasive cervical cancer
      • Kaposi sarcoma (KS)
      • Burkitt's lymphoma
      • Immunoblastic lymphoma
      • Primary lymphoma of the brain

DIAGNOSTIC STUDIES

  • HIV Detection Timelines:
    • It takes several weeks for HIV to be detected (window period).
    • Testing during this time can result in a FALSE NEGATIVE.
  • Types of Testing:
    1. HIV Antigen Testing (Blood):
    2. Rapid HIV-Antibody Testing:
    • Accurate and convenient, with results available in 20 minutes.
    • In-home HIV test kits available (saliva test).
    • Screens for antibodies, not for antigen.
    • If the rapid test is negative, assess risk and determine the need for repeat tests.

MONITORING TESTS

  • Components:
    1. CD4 T-cell Count:
    • Marker for immune function with a normal range of 800-1200 cells/μL.
    1. Viral Load:
    • Assesses disease progression; lower viral load indicates less active disease.
    1. Complete Blood Count (CBC):
    • Common observations include changes in WBC, lymphocytes, neutrophils due to the disease, and RBC, platelets due to ART.

INTERPROFESSIONAL CARE GOALS

  • Focus Areas:
    • Monitor HIV disease progression and immune function.
    • Initiate and monitor Antiretroviral Therapy (ART).
    • Prevent development of opportunistic diseases.
    • Detect and treat opportunistic diseases promptly.
    • Manage symptoms effectively.
    • Prevent or decrease complications from treatment.
    • Prevent further transmission of HIV.

DRUG THERAPY GOALS

  1. Reduce the viral load.
  2. Maintain or raise CD4+ counts.
  3. Prevent symptoms of HIV and opportunistic infections.
  4. Delay disease progression.
  5. Prevent HIV transmission.
  • Effectiveness of ART:
    • ART therapy can reduce viral load by 90-99% if taken consistently at the same time each day.

DRUG THERAPY STRATEGIES

  • Approach:
    • Attack HIV at different points in the replication process using various drug classes.
  • ART Combination:
    • Generally involves prescribing 3+ drugs from different groups at full strength, often in a single pill taken once daily.
    • This strategy helps reduce the risk of drug resistance.
  • Preventive Measures against Opportunistic Infections:
    • Immunizations (e.g., for hepatitis B, influenza, pneumococcal infections).

PRE-EXPOSURE PROPHYLAXIS (PrEP)

  • Definition of PrEP:
    • PrEP is a daily medication that can significantly reduce the chance of getting HIV.
    • Highly effective when adhered to daily; less effective if not taken consistently.
    • Important to note that while PrEP reduces HIV risk, only condoms protect against other STDs (e.g., syphilis, gonorrhea).

HIV PREVENTION

  • Strategies for Modification of Risk Behaviors:
    • Address risks related to sexual intercourse, drug use, perinatal transmission, and occupational exposure to HIV.
  • CDC Risk Reduction Tool:
    • Accessible at https://hivrisk.cdc.gov/

EDUCATION ON HIV MANAGEMENT

  • Improving Adherence to ART:
    • Education on timing, costs, side effects, and drug interactions (e.g., antacids, PPI, St John’s Wort).
  • Consequences of Poor Adherence:
    • Poor adherence can lead to treatment failure and increased viral load.

DELAYING PROGRESSION OF HIV

  • Importance of Early Treatment:
    • Initiating HIV treatment early is crucial to achieving an undetectable viral load.
    • Maintaining an undetectable viral load is essential to prevent transmission to HIV-negative partners during sexual activity.
    • Regular visits to healthcare providers and adherence to medication are vital for effectiveness.
    • Resources for finding a healthcare provider include locator.hiv.gov.

EDUCATION AND SUPPORT

  • Concept of Undetectable Viral Load:
    • Achieving an undetectable viral load signifies effective treatment.
    • Patients should report any concerning symptoms to their provider (see Table 14.9).
  • Utilizing Technology for Care:
    • Access to care provider networks and resources is essential for steady care and management.
  • Lifestyle Recommendations:
    • Promoting healthy eating and exercise contributes to overall health and supports the immune system in combating infections.

SOCIAL CONSTRUCTS

  • Social Stigma Associated with HIV:
    • Individuals with HIV may face stigma due to behaviors perceived as immoral or uncontrollable, leading to discrimination.
    • Discrimination often results in significant social impacts such as job loss, homelessness, and loss of insurance, disproportionately affecting women.
  • Legal Protection:
    • The Americans with Disabilities Act offers protections against discrimination for individuals with HIV.

MONITORING PROGRESS TOWARD HIV EPIDEMIC GOALS

  • CDC Indicators:
    • Incidence: Reduce new infections by 75% by 2025.
    • Diagnoses: Reduce new HIV diagnoses by 75% by 2025.
    • Knowledge of Status: Increase awareness of HIV status to 95% by 2025.
    • PrEP Coverage: Increase PrEP coverage to 50% by 2025.
    • Linkage to Care: Link 95% of newly diagnosed individuals to care by 2025.
    • Viral Suppression: Increase viral suppression rates among diagnosed individuals to 95% by 2025.