HIV/AIDS Flashcards
when does HIV become “AIDs”?
CD4 count below 200/ mm3 : when Opportunistic infections come about is “AIDS-defining illness”
what is the sequence that we use to Dx HIV?
HIV infection by ELISA (enzyme assay for antibodies) and then confirmatory Western blot
Viral load calculated by PCR, in copies/ mm3 (mm3 = microliter, or ul)
3 stages of HIV/AIDs
1) . Acute retroviral syndrome
2) . Asymptomatic stage
3) . Symptomatic stage (AIDS): Opportunistic infections (primary and reactivation)
what is the median duration of the asymptomatic stage?
10 years
what is going on with the virus during the asymptomatic stage? What about symptomatic? (weeds)
asymp: undergoing replication
symptoms: enough insult to the immune system to see an effect
when are the peak levels for viral load?
peak: around 2-4 wks after HIV exposure (acute syndrome)
drops down: for 8-10 years (latency)
peak: 12 -13 years post-exposure (overt AIDS)
when are the drops/rise for CD4 counts during the course of HIV/AIDS?
drop: around 2-4wks after HIV exposure (acute syndrome)
rise: 8-10 years (latency)
drop: 12-13 years post-exposure (overt AIDS)
transmission of HIV
via infected body fluids
excludes tears, aerosoles, saliva, GI contents
vertical HIV transmission:
~__% with no treatment (untreated HIV mom to baby), but
___ % with ____ monotherapy
30% no treatment
<10% with AZT (zidovudine) monotherapy
current therapy for vertical treatment of HIV? no breastfeeding reduces risk to < __%.
Current therapy: “triple therapy” (multidrug therapy)
no breastfeeding reduces risk to <1%
HIV is a ___ virus. with a ___ envelope and _____ on the surface
RNA, lipid envelope, glycoproteins (gps)
____ binds to T-helper cell CD4 receptor for attack
_______ are required for successful infection
gp 120 (glycoprotien) coreceptors.
what are the HIV coreceptors? What about those individuals who lack these?
CCR5 and CXCR4 (CCR5 for initial infection);
rare individuals who lack CCR5 can be exposed but are not infected
4 parts of HIV replication cycle
- Receptor binding
- Reverse transcriptase (RNA to DNA) by incorporating nucleosides
- Integrase incorporates into host DNA
- Protease is necessary to cleave viral proteins into structural peptides to produce new viral particles
if infected with HIV, one of three things can happen to CD4+ T cell. what are they?
- Replicate and fuse with cellular DNA or
- Cell death (apoptosis) or
- Virus sits in cell in latent state
what else can HIV virus directly infect (other than T cells) and what can it cause?
Brain –> encephalitis
Always check for all the ___ you can think of for an HIV person who has a single STI
STIs
much more aggressive course of TB infection if the patient has ___ as well.
HIV
Pearl: if a patient has current complaints of more than one distinct kind of ______ _____ or _______, be suspicious of HIV
Also be suspicious with _______ or ________
skin complaint or infection
widespread MRSA furuncles or boils
CDC recommends routine HIV screening for all persons ___ to ____ years of age in the United States. what is the “philosophy” for this testing.
13- 64
“Opt out”, rather than “opt in” philosophy for testing
- Minimally, if you test for any STD, include HIV in the test
Lab testing for HIV:
- order HIV test, will include _____ and if this is positive, will do confirmatory _____.
- Also if positive, Then need to do _____ and _____.
- _____ ______ (also helpful)
- if all positive…. what do you do?
- Order HIV test, will include a preliminary ELISA, and if positive, lab will do confirmatory Western blot
- May be indeterminate on WB - genotyping and phenotyping as a guide to retroviral therapy (some mutations confer resistance to specific drugs)
- viral load
- REFER!
acute HIV illness presentation ?
presents like any other acute viral illness
Clinical presentation for more advanced HIV: what three things should you note?
dementia, wasting, NOTICE opportunistic infections!
AIDS = HIV infection plus..
CD4+ count <200
or
Presence of an opportunistic infection
two major opportunistic infection types to note
candidiasis and lung infections (like pnuemocystic pneumonia (PCP) and toxoplasmosis)
what is the most common presentation of lung infection in AIDS? symptoms?
Pneumocystis jiroveci (PCP): (dyspnea, cyanosis, rales etc)
how do you Dx PCP?
induced sputum or bronchial lavage
txt for pcp
Treatment (21 days): Trimethoprim-Sulfamethoxazole (Bactrim)
how does one get toxoplasmosis?
Exposed through consumption of undercooked meat, ingestion of oocysts from cat feces