HIV Flashcards
what is HIV
retrovirus that attacks immune system
main immune cell impacted is CD4 cell- type of T-helper cell
- as a result body’s ability to fight infections become impaired
modes of transmission - body fluids (blood, breast milk, semen and vaginal secretions), vertical transmission (mother to baby)
what is the difference b/w HIV and AIDS
HIV - virus that damages cells in your immune system and weakens ability to fight everyday infections and disease
AIDS - used to describe no of potentially life-threatening infections and illnesses that occur when immune system has been severely damaged by HIV
while AIDS cannot be transmitted from 1 person to another- HIV can
where is HIV care now?
incurable but manageable chronic disease
patients with HIV have higher risk of - kidney disease, diabetes, CVD, certain cancers e.g. lymphoma
whats the advantage of patients being diagnosed early and adhering to ART
normal life expectancy
normal immune systems
when VL is undetectable = untransmittable
what are the monitoring parameters
viral load - measures amount of HIV’s genetic material in a blood sample
- upon first few weeks of contracting HIV - VL is extremely low
- Aim is undetectable (VL 20-50 copies/ML)
CD4 count - CD4 cell count is the number of blood cells in a cubic millimetre of blood
- AIM >200 cells/mm3
- risk of opportunistic infections increases as CD4 count declines
others - FBC, renal profile, LFTs, sexual health screen, adherence, resistance, glucose/HbA1c
what is HIV resistance?
when the virus mutates - allows virus to replicate in spite of ART
transmitted resistance - resistance of HIV to drugs in individuals who have never received treatment
acquired resistance - when drug-resistant strain of HIV emerges whilst on ART
cross resistance - when drug mutation against one drug causes other similar drugs to fail
how can resistance be prevented?
adherence - to keep undetectable VL <50 copies/mL - reduces risk of resistance and escalation to AIDS
some ARTs have higher barrier to resistance
opportunistic infection examples
pneumocystis pneumonia
- infection of lung
- caused by PCP
- treatment - steroids/co-trimoxazole
- prophylaxis - co-trimoxazole
toxoplasmosis
- caused by toxoplasma gondii
- treatment - sulfadiazine, pyrimethamine, folinic acid
- prophylaxis - co-trimoxazole
cryptococcus
- treatment - ambisome and flucytosine induction, fluconazole maintenance
describe the stages in HIV life cycle
HIV binds and fuses to CD4 cells
reverse transcriptase converts HIV RNA into DNA
integrase inserts viral DNA into host DNA
transcription and translation of viral mRNA to proteins
reconstitution and viral assembly
the stages of HIV and how it infects cells is imp to understanding classes of meds
what are the drug classes
entry inhibitors
NRTIs
NNRTIs
integrase inhibitors
protease inhibitors (PI)
NRTIs
NRTIs - nucleoside reverse transcriptase inhibitors
- most common backbone drugs
- inhibits reverse transcriptase which converts viral RNA to DNA
- prevent replication
- e.g. Abacavir, lamivudine, tenofovir
NNRTIs
NNRTIs - non nucleoside reverse transcriptase inhibitors
- bind directly to reverse viral reverse transcriptase disrupting its active site
e.g. doravirine, nevirapine, rilpivirine
integrase inhibitors
e.g. raltegravir, dolutegravir,
blocks action of integrase which inserts viral DNA into host cell DNA
entry inhibitors
e.g. maraviroc, enfuvirtide
entry inhibitors stop HIV entering human cells
2 types - CCR5 inhibitors and fusion inhibitors
generally not used in ART
protease inhibitors
e.g. lopinavir, darunavir, atazanavir
selectively bind and inhibit HIV protease which HIV uses to break up large polyproteins into smaller pieces needed for assembly of new viral particles
need boosters to be effective
