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
