Lecture 6: HIV Flashcards
how is HIV transmitted
sexually, parentally, through blood, mother to fetus
The risk of transmission
depends on the mode of transmission and degree of infectivity of the source. The highest risk of transmission is during receptive anal intercourse (1:100).
Mother to child transmission is x without treatment
25%
Do we need separate consent for HIV testing?
No but screening should be voluntary and only done if the patient agrees. If patient declines testing- should be documented in chart.
Other than semen or blood, fluids that transmit the disease are
breast milk and vaginal fluids
CDC recommendations for HIV screening
for all adults ages 13-65 (regardless of risk factors) at least once
What is the preferred method of HIV screening? What does it detect?
Fourth generation combination HIV test- detects both HIV-1 and HIV-2 antibodies and HIV-1 p24 antigen
For HIV-infected patients successfully treated with ART, what is their life expectancy?
life expectancies are now similar to those in the general population
What is the recommended screening for pregnant women?
ALL pregnant women regardless of risk factors each pregnancy (opt-out-screening)
What is the preferred method of HIV screening?
Fourth generation combination HIV test
P24
(short for protein 24) is a part of HIV-1 virus and can be detected in blood 2 weeks after transmission before antibodies are produced. Therefore, the forth generation test allows early HIV detection when antibody may not yet be detectable (before seroconversion).
If the combination test is positive…
then a confirmatory test is needed to differentiate HIV-1 from HIV-2 antibodies. If there is a concern for acute HIV infection, additional testing with HIV RNA (vital load) should be performed. Testing for HIV RNA (viral load) should not be used for screening.
Most opportunistic infections occur when CD4 falls below what?
200 with the exception of TB (can occur at any CD4 level). PCP pneumonia (pneumocystis pneumonia) is the most common opportunistic infection and a leading cause of death in patients with AIDS.
How does acute HIV infection present?
as mononucleosis type illness (fever, malaise, myalgia, sore throat, rashes) in patients with risk factors
If acute HIV is suspected what should you order?
HIV viral load (HIV RNA) and the forth generation combination test (HIV antibodies + HIV-1 antigen) should be ordered.
In US, when do we start treatment?
antiretroviral therapy (ART) should be initiated in nearly all HIV-infected individuals regardless of their CD4 count or presenting symptoms at the time of the diagnosis (after initial assessment).
significant drug interactions with HIV meds?
increased statins level (especially, simvastatin) and increased corticosteroid levels with protease inhibitors. Increased corticosteroid level may cause Cushing syndrome.
Most opportunistic infections occur when CD4 falls below what?
200 with the exception of TB (can occur at any CD4 level)
Post-exposure prophylaxis (sexual contact, needle stick) with antiretroviral medications (combination of medications) is recommended when?
if an individual had (1) an exposure to a source known to be HIV infected, AND (2) exposure was within 72 hours of presentation AND (3) exposure was to a fluid that could contain HIV virus (blood, semen, vaginal secretions). Post-exposure prophylaxis is not indicated for intact skin exposures and urine-source exposures. Start treatment as soon as possible.
concerns of non-HIV related comorbidities
• HIV infection is associated with a 50% higher risk of acute myocardial infarction beyond that explained by traditional risk factors (likely due to chronic inflammation and dyslipidemia caused by antiretroviral medications). Cognitive changes progressing to dementia are more prevalent in patients with HIV. HIV-associated cognitive changes can occur despite appropriate HIV control and adherence to antiviral therapy. People with HIV have elevated risk for non-Hodgkin lymphoma (x 77 higher) and cervical cancer (x 6 higher).
CD4 count significance
Assess status of immune system and a risk for opportunistic infections
When to order CD4 count?
Every 3-4 months for HIV infected patients to assess risk for opportunistic infections (falling CD4 count= an increased risk and poor prognosis)
Acute HIV infection presents as
mononucleosis type illness (fever, malaise, myalgia, sore throat, rashes) in patients with risk factors. If acute HIV is suspected, HIV viral load (HIV RNA) and the forth generation combination test (HIV antibodies + HIV-1 antigen) should be ordered.
The forth generation combination test cannot be used alone since
it is less sensitive than HIV RNA for detection of acute HIV infection. Viral load is very high during acute HIV infection therefore it is likely to be detected.
standard of care treatment
Combination of ART medications. •The main reason for combining medications is to reduce drug resistance. ART medications inhibit the HIV virus replication (making copies of itself), which reduces the amount of virus in the body. Having less HIV virus allows the immune system to maintain functions to fight opportunistic infections and cancers. HIV virus is suppressed but not eliminated (even in patients with undetectable viral load); therefore, the treatment is life-long (to keep the virus suppressed as long as possible). The goal of the therapy is to drive down viral load to undetectable level. ART therapy prolongs survival and decreases HIV transmission. Adherence to the ART regimen is a key determinate in the degree and duration of viral suppression.
HIV viral load (HIV RNA) is used
to (1) diagnose acute HIV, (2) assess response to the treatment (treatment failure FIRST manifests with a rising HIV viral load!). It is the best indicator for HIV virus activity and infectivity.
CD4
a surface molecule of T-helper lymphocyte and a target of the HIV virus. HIV virus causes continuous T-lymphocytes destruction. CD4 count is a good indicator of disease severity and level of immunity.
Most infections happen when the CD4 falls <
200 with the exception of TB (can occur at any CD4 level).
Vaccines contraindicated with HIV
Live vaccines (MMR, Zoster, Varicella, yellow fever) • are contraindicated in HIV individuals with significant immunosuppression (CD4 count less than 200).
Pre-exposure prophylaxis to
prevent sexual acquisition of HIV is recommended to HIV-negative individuals at high-risk (men who have sex with men, multiple sexual contacts, HIV discordant heterosexual couples). In 2012, the FDA approved Truvada (once daily) for pre-exposure prophylaxis. With adherence, Truvada prevents 92% of infections.
test: HIV viral load (HIV RNA) significant to
Diagnose acute HIV infection, Monitor response to treatment
HIV viral load (HIV RNA) when to order it
- If acute infection is suspected
- Every 3-4 months for HIV patients who receive ART to monitor response (rising viral load= treatment failure)
Combination test of HIV-1 and HIV-2 antibodies and HIV p24 antigen significance
Screening for HIV infection in asymptomatic individuals. Negative test do not require any additional tests.
Positive test requires confirmation with HIV-1/HIV-2 differentiation assay
Combination test of HIV-1 and HIV-2 antibodies and HIV p24 antigen when to order
- Screen for asymptomatic HIV infection
- Test for acute HIV infection in addition to HIV viral load (HIV RNA)
