HIV/AIDS Flashcards
What are the three clinical categories of HIV
A–> asymptomatic HIV infection; persistent generalized LAD; acute primary HIV infection
B–> symptomatic with conditions that are either attributed to HIV/defective cell mediated immunity or have clinical course complicated by HIV
C–> symptomatic with AIDS defining illnesses
what are the AIDS defining illnesses
PJP
kaposi sarcoma
recurrent bacterial pneumonia
candidiasis of esophagus or pulmonary system
(there are others)
what are the two types of HIV
HIV 1–> predominant type in most of the world except West Africa where type 2 predominates
HIV 2–> infection results in a similar clinical course to HIV 1 but degree of immune suppression and disease progression is slower
what is HIV
retrovirus that preferentially infects CD4 T lymphocytes
what % of new infections are in women
50%
how has the epidemiology of AIDS changes
estimated number of AIDS cases has remained the stable but number of cases among MSM, heterosexual adults and adolescents has increased, while cases among IVDU have decreased
risk factors for HIV transmission
viral load lack of circumcision sexual risk presence of ulcerative STD host and genetic factors
how is HIV transmitted
unprotected anal or vaginal sex
rarely oral sex
sharing of HIV contaminated needles and paraphernalia
vertical transmission
transfusion of contaminated blood or blood products
accidental exposures of health care workers
*it is NOT transmitted by casual contact, kissing, mosquito bites, toilets and shared utensils
what is the natural history of HIV in an UNTREATED patient
most patients, even without ARVs, survive for 10-12 years after acquiring HIV infection and are asymptomatic much of that time
what are the stages of HIV 1 infection
- viral transmission
- primary HIV infection
- seroconversion
- clinical latent period with or without persistent generalized LAD
- early symptomatic HIV infection
- AIDS
- Advanced HIV infection characterized by CD4 count below 50
how do you diagnose AIDS
AIDS indicator condition and CD4 count below 200 regardless of presence or absence of symptoms
what are two predictors of disease progression in HIV
CD4 cell counts
HIV viral RNA counts after 8-12 months of transmission (set point)
how do you diagnose HIV
serological detection of anti-HIV Ab, antigen or viral RNA is required
by 6 months after infection, anti0HIV Abs are present in 95% of people
what is the window between infection and seroconversion
3-6 weeks
*for recently exposed individuals (in the above window period) diagnosis can be made by detection of HIV in plasma (antigen testing)–a repeat ELISA at 6 weeks and 3 months is still indicated
what is the primary screening test for HIV
ELISA HIV antibody test
if the test is reactive, then repeat in duplicate. if either or both of those is reactive then the test is considered positive and a western blot or indirect immunofluorescence assay is done for confirmation
in which patients is a viral antigen test for HIV indicated
screening blood donors
screening neonates born to HIV infected mothers
what is HIV viral RNA detection testing used for
monitor disease progression and ARV therapy response
when should routine HIV testing occur
at the time of the initial visit
all testing must be voluntary, confidential and done with the patients consent
how should HIV testing be done if a specific exposure has occurred
baseline antibody testing should be obtained with repeats at 6, 12 and 24 weeks (same as exposed health care worker)
if patient has possible symptoms of primary HIV, viral load testing should be performed in addition to antibody testing
what are the most common causes of false positive testing in low risk patients
recent immunization
repeat serologic testing
HIV viral RNA level in 1-3 months
list 4 goals of HIV therapy
- durable suppression of HIV viral load to less than 50 copies/mL
- improvement in quality of life
- preservation of future therapeutic options
- restoration of immune function (as indicated by CD4 cell count)
list two potential risks of HIV therapy
- higher risk of long term antiretroviral dug toxicities due to a considerable increase in the duration of antiviral exposure
- evolution of drug resistance if therapy fails to completely suppress viral replication (thus need to stress compliance)
in which patients should you absolutely start ARV therapy
pregnant women
patient with HIV associated nephropathy
patient coinfected with HBV
patient with CD4 cell count below 350
patient with history of AIDS defining illness
how should you manage an HIV positive patient with a CD4 count above 350
assess clinical scenario, patient readiness, age, comorbidities, potential impact on quality of life and adherence factors
then decide if ARV therapy should be pursued
what classes of drugs are available for treatment of HIV
nucleoside and nucleotide transcriptase inhibitors (NRTIs)
non nucleoside reverse transcriptase inhibitors (NNRTIs)
protease inhibitors (PIs)
fusion inhibitor
integrase inhibitor
CCR5 antagonist
fixed dose combinations including: Combivir Trizivir Epzicom Truvada
how many ARVs are generally included in HIV therapy
at least 3 active ARVS
base is either an NNRTI or a PI
backbone typically consists of two NRTIs
how do you pick an ARV regimen for a patient
should be individualized, and should be based on a number of factors including:
comorbid medical conditions drug interactions adverse effects pregnancy potential genotyping etc
how should viral load change after initiation of ARV therapy
should decrease 3-4 fold within 2-8 weeks and continue to decrease thereafter
goal is to have undetectable viral load at 6 months
when should HIV viral load be undetectable after initiation of ARV therapy
within 6 months
when should you change treatment for HIV
treatment failure
adverse effect
noncompliance due to adverse effects
what are some signs of a failing ARV regimen
unable to achieve or maintain suppression of viral replication below 50 copis
increasing viral load
decreasing CD4 cell count
clinical deterioration
what are some adverse events that can arise from ARV therapy
lactic acidosis
lipodystrophy
hyperlipidemia
peripheral neuropathy
GI symptoms
renal insufficiency
rash
other than ARV, what treatments can be offered to the HIV positive patient
prophylaxis for opportunistic infections when indicated by CD4 count
immunizations early in disease
at what CD4 count should you start prophylaxis for PJP
less than 200
at what CD4 count should you start prophylaxis for toxoplasmosis
less than 100
at what CD4 count should you start prophylaxis for MAC
less than 100
at what CD4 count should you start prophylaxis for CMV
less than 50
at what CD4 count should you start prophylaxis for TB
if PPD has 0.5 mm induration
what type of sexual activity is greatest risk for HIV transmission
receptive anal intercourse (8fold higher risk)
–risk is 1.5% per act with an infected individual
what steps can be taken to reduce risk of transmission from mother to child in vertical transmission
c section for delivery
prenatal ARV therapy
ARV therapy in the newborn immediately after birth
avoid breastfeeding (unless local conditions make this unsafe)
how do prior or current STD infections raise risk for transmission of HIV
G and C increase HIV transmission risk by 3 fold
syphilis by 7 fold
herpes by up to 25 fold during an outbreak
how does acute seroconversion with HIV present
flu like illness–> fever, malaise, generalized rash
what is often a presenting complaint for HIV
generalized LAD
how does AIDS manifest
recurrent, severe, occasionally life threatening infections and/or opportunistic maligancies –> thus, HIV should be suspected when unusual infections present in apparently health individuals
what are some sequelae of HIV itself
AIDS associated dementia/encephalopathy
HIV wasting syndrome (chronic diarrhea and weight loss with no identifiable cause)
are there any findings specific to HIV infection
no
the physical findings are those of the presenting infection or illness
generalized LAD is common, weight loss may be apparent
what might clue you in to HIV infection in a presenting patient
evidence for risk factors (MSM, IVDU, vertical transmission, multiple sexual partners)
minor opportunistic infections i.e herpetic lesions on the groin, widespread oral candidiasis
given that opportunistic infections and cancers can arise on people without HIV but with other immune disorders etc, what other etiologies should you consider in someone presenting with an infection or malignancy associated with HIV
chemotherapy
immune disorders
severe combined immune deficiency
severe malnutrition
i.e a young adult undergoing chemotherapy
what are the most effective methods, on an individual level, for preventing HIV
avoidance of sexual contact outside a monogamous relationship
the use of safer sex practices for all other sexual encounters
abstinence from nonmedical parenteral drug use
what % of new HIV infections were transmitted by HIV infected persons undergoing treatment with viral suppression
0%
based on march 2019 CDC reporting
(51% of the US HIV positive population is undergoing treatment with viral suppression, and they transmitted 0% of new infections)
what are some prevention methods that people can use with their partners, or if they are in high risk populations, to help prevent HIV transmission
condom use
pre-exposure prophylaxis (PrEP)
prevention methods for HIV
abstinence when possible
reduction in number of sexual partners
using barrier contraception
treatment of concurrent STDs
testing of self and partner for HIV infection and other STDs
what is the most well known risk factor that predisposes to HIV transmission
concomitant infection with other STDs as they may cause mucosal ulcerations or tears
what risk factor in women (a med) may increase risk of transmission of HIV
OCP
who should be considered for PrEP (per 2014 CDC guidelines)
anyone who is in an ongoing sexual relationship with an HIV infected partner
a gay or bisexual man who has had sex without a condom or has been diagnosed with an STI within the past 6 months and is not in a mutually monogamous relationship with a partner who recently tested HIV negative
a heterosexual man or woman who does not always use condoms when having sex with partners known to be at risk for HIV and is not in a mutually monogamous relationship with a partner who recently tested HIV negative
anyone who, in the preceeding 6 months, has injected illicit drugs and shared equipment or been in a treatment program for illicit drug use
- daily oral PrEP has been shown to be safe and effective in reducing the risk of sexual HIV transmission in adults, adolescents and discordant couples
- acute and chronic HIV infection must be excluded by symptom history and HIV testing immediately before PrEP is prescribed
- oral PrEP for coitally timed or other noncontinuous daily use is not recommended
how does compliance affect efficacy of PrEP
among those who took their PrEP as prescribed (daily) 90% of days, HIV transmission risk was reduced by 73%
in those who used it less than 90% of the time, risk was only decreased by 21%
what are the long term monitoring guidelines for HIV
in patients on ARVs, do the following every three months:
basic chemistry profile
LFTs
CBC-D
fasting glucose every 6 months
fasting lipids every 12 months
in patients on a stable regimen whose viral load is suppressed and whose CD4 count is well above the threshold for opportunistic infection risk, CD4 count may be monitored every 6-12 months (3-6 months if these conditions are not met)
