HIV Flashcards
what is the human immunodeficiency virus?
it’s an enveloped retrovirus w/ 2 copies of ssRNA genome
what does the timeline of HIV infection look like?
- primary infection (acute HIV infection) s/s within the first 2-4 weeks ➔ flu-like
- clinical latency ➔ can last from 4 weeks onto years until reactivation
- onset of s/s of decreased CD4+ T cells w/ opp infections, progressing into AIDS
what are the two types of HIV and which is more common and virulant?
HIV-1 and HIV-2
HIV-1 more common and virulent vs HIV-2
RF to getting HIV infection
- unsafe sexual practices
- IV drug use
- other STI - syphillis, herpes, chlamydia, gonorrhea, and bacterial vaginosis
- MSM
- harmful use of alcohol or drugs in the context of sexual behaviour
- vertical transmission
- blood transfusions or products
what is the prognosis of someone living with HIV?
properly treated - life expectancy is the same as uninfected
untreated - 1-2 years post first opportunistic infection
how is HIV transmitted?
- sexual - direct transmission of infected fluids via intercourse
- needle or instrument related w/ blood-contaminated needles/instruments
- transfusion or transplant related
- vertical - from mother to child during preg or via breast milk
how does HIV replicate once within the body?
- HIV entrance
- HIV binds to CD4+ via gp120
- HIV ssRNA enters the cell w/ its reverse transcriptase, integrase, and protease
- reverse transcriptase it’s viral RNA into viral DNA
- integrase the viral DNA into the host CD4+ cell DNA
- uses host machinery to replicate viral DNA ➔ immature virions
- budding of the cell to release immature virions
- the protease cleaves the immature virions into mature that can infect other cells
what s/s could you see in the clinically latent stage?
from 4 weeks post exposure onwards
typically asymptomatic
can experience some lymphadenopathy, diarrhea on and off, and some level of opportunistic infections but that is leading into the later stage/AIDs level
explain how the number of CD4+ cells decreases throughout the course of HIV infection, and how HIV RNA levels change
- primary/inital infection - CD4+ T cells normal and HIV RNA levels low (still need to replicate)
- as the amount of HIV RNA increases in the body there is a decrease in CD4+ T cells as they die with the replication ➔ widespread distribution of virus into the lymphoid organs
- at the end of the acute HIV infection ➔ time of clinical latency where CD4+ T cells continue to decline slowly as HIV RNA levels stay relatively constant
- some level of HIV control via humoral and cellular immunity vs the virus, but not enough to fully eradicate as the virus continues to mutate - CD4+ T cells reach a critical low, that impairs immunity and allows for opp infections and for HIV RNA levels to rise ➔ verging into the territory of AIDS
what s/s could you see in the acute stage of HIV?
the 2-4 weeks postexposure
- typically asymptomatic
otherwise may experience non-specific flu-like s/s like fever, malaise, myalgia, pharyngitis, N/V/D and rash
how would you define late stage/AIDS?
symptomatic portion of infection w/ at least 1 AIDS defining illness and a CD4+ count < 200 cells/mcL and <14% of all T cells
what are some examples of AIDS-defining illnesses?
Worsening syndromes:
- candidiasis of the esophagus, resp tract (NOT mouth)
- encephalopathy - HIV related
- recurrent pneumonia
- wasting syndrome from HIV
Cancers:
- invasive cervical cancer
- Lymphoma (Burkitt’s etc. )
- Kaposi sarcoma
Opp infections:
- disseminated mycobacterial infections (TB etc.)
- toxoplasmosis of brain
- recurrent salmonella
- histoplasmosis
How can we screen for HIV?
can offer it as a part of normal STI screening w/
HIV serology - antibody-antigen test or a POC finger prick test
how would we diagnose HIV? what test is diagnostic?
HIV serology - the immunoassay - to check for HIV proteins in the blood and determine if HIV-1 or HIV-2
*done after already doing the antibody-antigen test
also do viral load for HIV
what lab work would you do while managing an HIV pt post dx?
- CD4+ T cell cound
- viral load
- genetic drug resistance re: HIV to ensure tx is targetted
- Liver - bilirubin, ALT/ALP/GGT
- CBC with diff
- kidney: creatinine/urea
- metabolic: electrolytes
- lipid profile – could interact with antivirals
- pregnancy test
other STIBBI ix: hep B, hep c, syphillis, chlamydia and gonorrhea
what physical exams would you do while managing an HIV pt post dx?
PAP test for females
look for derm rashes that may indicate some sort of opp infection
overall full system physical based on s/s
what antiretroviral therapy is available for HIV pts?
- nucleoside/nucleotide reverse transcriptase inhibitors
- protease inhibitors
- integrase inhibitors
- CCR5 inhibitors
explain the concept of PrEP and who is offered PrEP
Pre exposure prophylaxis
explain the concept of PEP and who is offered PEP
Post exposure prophylaxis: idea is to prevent HIV after a possible exposure to stop the HIV infection from taking root
- must be started within 72h of suspected exposure and med course over 28d
for those with a high risk exposure to HIV
- if partner is HIV+ or unknown HIV status and of a high prev of HIV population
- if sexual practices invovled anal or vaginal sex
- if there was a gap or failure of protection
- sharing drug-injection equipment is always high risk
- health care workers - needle stick
what sort of pt education would you offer someone newly infected with HIV?
- safe sex
- disclosure to sexual partnerrs
- stay UTD with vaccinations
- importance of compliance with medications ➔ Undetectable = untransmissable
