HIV Flashcards
What is the structure of the HIV virus?
Genome is a ssRNA virus with lipid membrane
Contains reverse transcriptase and integrases.
What cell does it target?
T Helper cells
macrohages and monocyets
Name and describe the stages of HIV infection.
Primary infection or seroversion- first 1-3 months
Latent infection (while host immunity lowers viral loads and CD4 count returns to near normal levels)
Symtomatic infection 350cells per microliter (CD4)
AIDS less than 200 cells per microlitre (CD4)
How do we treat HIV and who gets treatment?
Anti-retrovirals (target binding and fusion, reverse transcriptase, integrate or the viral maturation and spread phase).
Every body with HIV should be treated regardless of CD4 count.
Some work on a vaccine.
Which groups of people are most likely to develop HIV?
Globally heterosexuals (women more than men) UK MSM
What is the chance of HIV transmission from a needle stick injury on a treated low viral load HIV Patient?
1/333
What are the big practice interventions we can make to prevent spread of HIV?
Partner tracing
Post exposure prophylaxis
Condom use
Antiretrovirals in HIV patients
What are the initial signs of HIV infection?
Non specific flu like symptoms
What cancer is associated with HIV?
Kaposi Sarcoma
What oral infection may lead you to think of HIV testing?
Thrush
What is PCP and what might it indicate.
Pneumocystitis pneumonia associated with HIV
Someone who has had coldsores in the past but very infrequently presents suddenly having had 6 in 6 months, what might you suspect?
HIV often results in reactivation of latent viruses
Other than viruses what other microbes does HIV particularly present with?
Yeast, Protozoa and Moulds.
Most HIV patients live a long life with chronic infection so why do some people die?
Late diagnosis
How many cases are there of HIV in the UK?
103,000 67% of which are men
How does UHL perform HIV tests?
Opt out basis as rate is 3.8/1000
57% of HIV in the UK is amongst the black african population, but what is the gender split in this group?
1/56 men
1/22 women
Why could HIV be seen to be more serious in heterosexuals in that it carries a higher mortality rate?
> 50% are diagnosed late
What percentage of people with HIV in the UK don’t know?
17%
How does HIV effect the cell?
Replicates in the cell, destroys the cell, causes inflammation and then spreads.
How does HIV infect cells?
Free Virus binds and fuses CD4 molecules and one other co-receptor (CCR5 or CXCR4).
Virus penetrates the cell membrane and empties its content. The ssRNA is then reverse transcribed to DNA. The DNA is then integrated into hosts nuclear genome by integrate. The host cell transcribes and translates microbial proteins. Viral RNA assemble and new immature viruses bud off.
How is HIV transmitted?
Contact with infected bodily fluids and mucous tissue/ blood or skin breaks.
Sexual contact, transfusions, needles and perinatal.
What factors effect transmission?
Exposure type
Viral load
Condom usage
Breaks in skin of mucousa
What is the most risky activity for HIV transmission?
Receptive Anal Sex
Whats the risk in blood transfusions?
90-100%
How can we diagnose HIV?
Blood test - serology (antigens and antibody), shows up at 4 weeks and results on the same day but false negatives possible.
Blood test PCR is highly sensitive even in early infection but is low and expensive so is not used as an initial HIV test.
Rapid tests are low cost and results in under an hour- look for HIV antibody in blood or saliva. Available as a postal test. False negatives can occur and thus need confirmation with serology.
What are the aims of HIV treatment?
Undetectable viral load Normal CD4 count Reduce inflammation Reduce transmission risk Good quality of life Normal life expectancy
Who should be tested? (Hint split down to body systems)
Everyone if rate is >2/1000 Resp px: bacterial pneumonia or TB Neuro px: meningitis/dementia Derm px: severe psoriasis, reccurent shingles Gastro px: chronic diarrhoea, weight loss Haem px: anything unexplained. Onco px: lymphoma, anal canncer Gynae px: CIN GU px: Any STI, Hep B or C
Give some examples of specific HIV treatments and their mechanisms of action.
Nucleotide revers transcriptase inhibitor - Emtricibine
Non-nucleotide reverse transcriptase inhibitor: Efavirenz
Protease inhibitor -Darunavir
Integrase inhibitor- Dolutegravir
(note one of a NRTI should be prescribed with one other)
Give some examples of specific HIV treatments and their mechanisms of action.
Nucleotide revers transcriptase inhibitor - Emtricibine
Non-nucleotide reverse transcriptase inhibitor: Efavirenz
Protease inhibitor -Darunavir
Integrase inhibitor- Dolutegravir
CCR5 inhibitor Maraviroc
(note one of a NRTI should be prescribed with one other)
Why do we give 3 ARV?
Millions of replications per cell in a day so lots of mutations meaning drug resistance to mono therapy can develop with in days. We need patients to take the trio consistently to avoid resistance.
List strategies in treating and lowering HIV prevelence.
Condom use Prevent vertical transmission ARV treatment as a preventative Medical circumcision Post and pre exposure prophylaxis
Name the ethical dilemmas in HIV.
Psychological impact of the diagnosis
Dealing with stigma
Patient confidentiality - who else is at risk?- children, partners and HCW
How is post exposure prophylaxis given?
risk assessed
3x daily ARV for 28 days
Start with in 72 hrs (ASAP)
HIV baseline and test again at 1 and 3 months
