HIV Comprehensive Study Notes

HIV Overview

  • HIV is a virus that attacks the immune system, specifically CD4 or T cells (helper T cells), which are essential for fighting infections.
  • If untreated, HIV can lead to AIDS, the final and most severe stage of the infection.
  • There is no cure for HIV, but highly effective treatments exist: antiretroviral therapy (ART) reduces the viral load to undetectable levels, prevents transmission, and is a lifelong commitment.
  • AIDS is defined by a CD4 count < 200200 cells/µL or by the presence of one or more AIDS-defining illnesses; AIDS is the end stage of HIV infection.
  • HIV is transmitted through contact with certain infected body fluids; prevention relies on reducing exposure and maintaining treatment.
  • HIV is not spread through casual contact (hugging, sharing a toilet, mosquitoes); casual transmission is extremely unlikely.

Modes of Transmission

  • The main transmission routes are:
    • Unprotected sexual contact (vaginal, anal, or oral sex).
    • Blood-to-blood contact (shared needles, syringes, transfusions with infected blood, needle-stick injuries).
    • Mother-to-child transmission during pregnancy, childbirth, or breastfeeding (vertical transmission).
    • Transfusions with infected blood.
  • The infection is not spread by casual contact, insects, air, or water.
  • The most common route of transmission worldwide is sexual transmission.

Transmission Through Body Fluids

  • Transmission requires direct access to the bloodstream or exposure to infected body fluids such as:
    • Blood
    • Semen
    • Vaginal fluids
    • Rectal fluids
    • Breast milk
  • Fluids that do not reliably transmit HIV (unless visibly contaminated with blood) include saliva, sweat, and tears.
  • Saliva, sweat, or tears are not considered transmission fluids under typical circumstances.

Acute vs. Chronic Infection and AIDS

  • There are three main stages of HIV infection:
    • Stage I: Acute HIV infection (2 to 4 weeks after exposure)
    • Stage II: Chronic HIV infection (clinical latency)
    • Stage III: AIDS

Stage I: Acute HIV Infection

  • Timeframe: about 2−4 weeks2-4\text{ weeks} after exposure.
  • Characteristics:
    • High viral load and very infectious.
    • Flu-like symptoms may occur; many patients are symptomatic or mistaken for a common viral infection.
    • Symptoms can include fever, sore throat, fatigue, rash, lymphadenopathy, myalgia.
  • Virology and testing:
    • HIV RNA or NAT can be positive within 7−14 days7-14\text{ days} after exposure.
    • Fourth-generation antigen/antibody tests typically become positive within 2−6 weeks2-6\text{ weeks}; antibody-only tests may still be negative.
  • Clinical focus: early diagnosis allows timely treatment to improve outcomes and reduce transmission risk.
  • Monitoring and treatment: start ART promptly to suppress replication and protect immune function.

Stage II: Chronic HIV Infection (Clinical Latency)

  • Timeframe: can last years to decades if untreated; with ART, individuals can remain in this stage indefinitely.
  • Virology: the virus remains active but reproduces at low levels; CD4 counts gradually decline; viral load may be stable with treatment.
  • Symptoms: often asymptomatic or with mild symptoms such as swollen lymph nodes or fatigue.
  • Monitoring and management:
    • Regular monitoring of CD4 count and viral load.
    • Start and maintain ART.
    • Prevent opportunistic infections with vaccines or prophylaxis.

Stage III: AIDS

  • Diagnosis criteria: CD4 count < 200200 cells/µL or presence of one or more AIDS-defining illnesses.
  • Virology: high viral load with severely weakened immune function.
  • Symptoms and complications:
    • Opportunistic infections (e.g., Pneumocystis pneumonia) and opportunistic cancers (e.g., Kaposi sarcoma, tuberculosis, cryptococcal meningitis, toxoplasmosis).
    • Severe weight loss, fatigue, chronic diarrhea.
  • Treatment focus:
    • Initiate ART and treat or prevent opportunistic infections.
    • Provide supportive care.
  • NCLEX tip: AIDS is not a synonym for HIV; AIDS is the end stage of HIV infection.

HIV Testing and Diagnosis (Overview)

  • HIV testing detects infection by identifying:
    • The virus itself,
    • Its antigens, or
    • The body's antibodies to it.
  • Early diagnosis allows timely treatment, reduces transmission, and improves outcomes.
  • Testing modalities include:
    • ELISA or rapid antibody/antigen tests (fourth-generation tests)
    • Nucleic acid tests (NAT) to detect viral RNA
    • Confirmatory testing with Western blot or a similar confirmatory assay
  • Testing sequence:
    • Initial test: ELISA or rapid test or fourth-generation test
    • If initial test is positive: confirm with Western blot or an equivalent confirmatory test
    • NAT can be used to detect viral RNA and may confirm infection earlier in acute infections

HIV in Pregnancy and Vertical Transmission (Mother-to-Child Transmission)

  • Transmission can occur during:
    • Pregnancy (in utero) or crossing the placenta
    • Labor and delivery (during birth, exposure to maternal blood and vaginal secretions)
    • Breastfeeding (postpartum via breast milk)
  • With proper care and ART, the risk of mother-to-child transmission can be reduced to < 1%1\%.
  • Risk factors for vertical transmission include:
    • High maternal viral load
    • Co-infections
    • Poor maternal health
  • Perinatal delivery considerations:
    • If viral load at delivery is < 10001000 copies/mL, vaginal delivery is possible (typically around 37 weeks to term).
    • If viral load at delivery is > 10001000 copies/mL, cesarean section is recommended (typically around 38 weeks).
    • Avoid artificial rupture of membranes, scalp electrodes, forceps, and episiotomy if possible.
  • Maternal antiretroviral therapy (ART) during pregnancy:
    • All HIV-positive pregnant women should be started or continued on ART regardless of CD4 count or viral load.
    • Preferred regimen: two NRTIs and one integrase inhibitor.
    • Goal: undetectable viral load by delivery.
    • Monitoring: CD4 count and viral load at initiation of prenatal care, every trimester, and near delivery (34–36 weeks).
  • Newborn management and testing:
    • Start zidovudine (AZT) within 6−12 hours6-12\text{ hours} of birth.
    • High-risk infants may receive a three-drug ART regimen and prophylaxis for 4−6 weeks4-6\text{ weeks}.
    • HIV testing for the infant: PCR testing at birth, 2–3 weeks, 1–2 months, and 4–6 months.
    • Antibody tests are unreliable in infancy due to maternal antibodies.
    • Avoid breastfeeding if possible; by following guidelines, ~99%99\% of HIV-infected women will not pass HIV to their infants.

Nursing Considerations and Standard Precautions

  • Nurses should consistently follow standard precautions for HIV-positive patients.
  • Focus areas include:
    • Regular monitoring of viral load and CD4 count
    • Lifelong ART adherence regardless of symptoms
    • Screening and treatment for sexually transmitted infections
    • Monitoring for ART side effects (e.g., anemia, nausea, liver or kidney effects)
    • ART adherence is critical to maintain an undetectable viral load, preserve immunity, prevent opportunistic infections, and reduce transmission
  • Common ART regimens include combinations of:
    • NRTIs, NNRTIs, protease inhibitors (PIs), and integrase inhibitors
  • HIV-positive women can become pregnant and have healthy HIV-negative babies with proper management

ART During Pregnancy and Safer Conception

  • ART during pregnancy markedly reduces vertical transmission.
  • Safer conception practices and contraception are essential.
  • Dual protection strategies include condom use and appropriate contraception.
  • Hormonal birth control considerations: potential drug interactions with ART exist; monitor effectiveness when using methods like IUDs or hormonal contraception.
  • Vaccination and preventive care:
    • Ongoing cervical cancer screening is important because HIV-positive women have higher risk for HPV-related cervical dysplasia; Pap smears are recommended at HIV diagnosis and annually; colposcopy may be required for abnormal results.
  • Medication adherence strategies:
    • Use pillboxes and reminders; educate on ART and side effect management

Prevention and Public Health Measures

  • Prevention strategies include:
    • Consistent condom use
    • Regular HIV testing and knowing one’s status
    • Avoid sharing needles
    • Pre-exposure prophylaxis (PrEP) for high-risk individuals
    • Post-exposure prophylaxis (PEP) is implied by context of exposure management in health care settings
    • Universal precautions in health care settings
  • Vaccination and STI management to reduce transmission risk

Other Key Points and Practical Implications

  • HIV testing is most effective when performed early; early diagnosis improves outcomes and reduces transmission.
  • The term AIDS refers to the final stage of HIV infection, not to HIV itself.
  • Transmission risk estimates highlighted in the material:
    • Vertical transmission without ART: 15% to 45%15\% \text{ to } 45\%
    • Vertical transmission with ART: <2\%
    • Per single needlestick exposure: <0.3\%
  • Transmission through casual contact is not a concern, and infections are not spread by insects like mosquitoes.
  • For health care providers, adherence, monitoring for ART side effects, and comprehensive care (nutritional, psychosocial) are essential to optimize outcomes for both mother and infant.
  • Important clinical reminders: begin ART immediately in pregnancy, avoid live vaccines if CD4 count is < 200200, and continue Pap smears annually for HIV-positive individuals.
  • In high-resource settings, breastfeeding is generally not recommended for HIV-positive mothers to minimize postnatal transmission risk.