Diagnosis and management of HIV I Flashcards
HIV is what type of virus?
lentivirus (retrovirus)
HIV-1 features
- infects and depletes CD4+ T cells
- high genetic mutation rate
- evades antibody and cellular immunity
- defies traditional vaccine strategies
- hides in resting memory CD4+ T cells
AIDS = CD4+ T cell count under what value? what is the other definition of AIDS?
200
or AIDS indicator disease
what is the viral load “set point / inflection point”?
point when the viral load stabilizes
what is a normal CD4+ T cell count?
over 750
at what CD4+ T cell count does Kaposi’s sarcoma present?
400
at what CD4+ T cell count does AIDS dementia present?
~250
at what CD4+ T cell count does wasting present?
~150
at what CD4+ T cell count does toxoplasmosis and cryptococcosis present?
100
at what CD4+ T cell count do CMV and mycobacterium avium complex present?
50
what group constitutes the highest % of new HIV diagnoses?
MSM
what is the rationale for using PREP (pre exposure prophylaxis)? is it successful?
targeting high risk groups (MSM, heterosexual contact, injection drug use)
it has been shown to be successful in these groups
what age group has the highest HIV diagnoses?
25-34
what ethnic group represents the highest amount of new HIV diagnoses?
African Americans
what % of people with HIV do not know they have it? what % of new infections do they account for?
20%
52%
what is critical in the management and especially prevention of HIV? what is the goal?
retention in care - likely to get patients on HIV meds and keep them on them
goal is to get viral load undetectable
persons with acute HIV infection are likely to have
A. no symptoms
B. positive HIV western blot
C. high level of HIV RNA in blood
D. delta 32 CCR5 homozygosity
asdf
in acute retroviral syndrome, flu- or mono-like syndrome is present in what % of cases?
75%
when are symptoms usually seen in HIV infection?
burst in viremia
in acute retroviral syndrome, pharyngitis, rash, and/or headache is present in what % of cases?
50%
what do diagnostic tests look for to detect HIV?
- look for presence of virus (PCR)
- look for presence of antigen (p24)
- look for presence of antibody (anti-p24)
what is the viral antigen detected in HIV testing? what part of the virus is it? when is it detected?
p24 (capsid protein)
detected 1 week before HIV antibody
when is HIV RNA detected? does this require confirmation?
1-3 weeks before detection of HIV antibody
yes, requires confirmation
does the antibody / antigen test require confirmation?
yes
what is the gold standard screening test for HIV?
ELISA
what are the HIV confirmatory tests?
- HIV-1 western blot
- multispot HIV-1 / HIV-2 test (becoming gold standard)
what is the two step testing for screening and confirmatory testing?
- reactive HIV Ag/Ab screening test
- multispot HIV-1 and HIV-2 discriminatory assay
- if POSITIVE multispot HIV-1 and HIV-2 discriminatory assay = report as HIV positive
- if NEGATIVE multispot HIV-1 and HIV-2 discriminatory assay = HIV-1 nucleic acid testing
- if POSITIVE HIV-1 nucleic acid testing = HIV positive
USPSTF screening protocol
- persons age 15-65
- grade A recommendation
what is opt-out testing for routine HIV testing?
- repeat testing based on risk
- all pregnant women MUST get tested (Iowa law)
what are the HIV coreceptors?
CCR5
CXCR4
which virus is typically transmitted via sexual contact?
R5 tropic virus
which HIV coreceptor is essential for transmission from person to person ?
CCR5
which HIV coreceptor is associated with more rapid disease progression?
CXCR4
can the tropism of HIV infection change? how does it relate to AIDS progression?
yes
shift from CCR5 to CXCR4 indicates a faster progression to AIDS
what are the benefits of the delta 32 CCR5 mutation?
does not cause human disease
normal CCR5 ligands are beta-chemokines
