HIV Flashcards
there are 2 types of HIV - 1 and 2
which is reponsible for the global epidemic
1 is reponsible for the global epidemic
2 is less pathogenic and is seen in west africa mainyl
outline the HIV life cycle
- bind to surface of CD4 T cell
- fusion of HIV and CD4 membranes
- inside the T cell the HIV releases RT enzyme to converts its genetic material from RNA into DNA - this means that it can be combined with the T cell’s DNA
- HIV DNA goes into T cell nucleus and combines with it’s DNA using integrase
- HIV uses the T cell machinery to replicate itself
- new HIV sits on the surface of the cell in long chains as immature (non infectious) HIV
- this is cleaved by protease enzyme to form smaller infectious HIV
what happens to HIV and CD4 T cell numbers as with untreated disease progression
HIV increases and CD4 T cells decrease - worsening immunosuppression
outline the progression of HIV/development of AIDS
- during primary infection, HIV levels are high in the bloodstream but no IS features as CD4 T cell levels are still high
- HIV Ab have not yet been formed
waht is seen on a blood film of someone with HIV
aypical mononuclear lymphocytes
what is the T cell parameter for AIDS
<200 (normal is 500-1600)
how is HIV transmitted
exposure of mucosal surfaces to infection body fluids
where are the current pandemics?
sub sahran Africa, caribeean and SE Asia
who is screened for HIV
- clinical situations:
- antenatal care and assisted conception services
- GUM clinics, abortion clinics, drug dependecy services
- there is universal screening in some high prevalence areas
- high risk groups - MSM, women w/ bisexual man, PWID, HIV partner
- clinical indicators
what is the most common type of AIDS lung disease
pneumocystc jirovecii pneumonia
this is onyl really seen in the IC
how does PC pneumonia present
non specific, insidious onset, SOB and dry cough etc
managemenet of PC pneumonia
high dose co-trixomazole
is prophylaxis given for any OI
PC pneumonia - co-trixomazole (if CD4 <200)
what does toxoplasmosis cause in AIDS
focal CNS disease - brain abscesses etc
which 2 organisms cause chorioretiniis in IC patients
toxoplasma gondii and CMV
how does CMV present
ofte subclinical
causes retinitis, colitis and CNS disease
what are the associated depression and anxiety in HIV positive related to
partly due to psychosocial impact of disease but there may also be changes in mental state or congition due to an organic cause
what is the main CNS pathogen
toxoplasma gondii
name 3 manifestations of acute CNS disease
transient meningoencephalitis, myeloapthy and neuropathy
what are the chronic manifestations of CNS disease
dementia, vaious encephalopathies, motor dysfunction
what is progressive multifocal leukoencephalopathy
progressive damage/inflammation of teh white matter
the JC virus infects the oligodendrocytes, leading to demyelination
HIV associated wasting
unexplained loss of >10% of body weight - visible thinning of face, waist and extremities
kaposi’s sarcoma
a vascular tumour, commonly found on mucocutaneous sites but can involve lymph nodes and organs
what virus is Kaposi’s sarcoma also associated with
Human herpes virus 8
there are 2 available tests for HIV: ELISA screening for HIV antibodies and 4th generation tests
what is the difference between them
- ELISA looks for antibodies to HIV - IgG and IgM etc
- Seroconversion may take up to 3 months, so in this period you may get a false negative result
- 4th generation looks for antibodies and p24 antigen. the p24 antigen is prsent from around 10 days - reduces window period of inaccuracy
what are the rapid tests
these are simplified ELISA tests that allow for testing in resource poor settings
they are looking for HIV Ab in the blood and the stick changes colour if positive
can use fingerprick specimen or saliva
what are the disadvantages of rapid tests
they are expensive, quality control, may not be reliable in early infection, poor positive predictive value in low prevalence settings
on discovering someone has HIV, what testing is done
pregnancy test before starting ART
STI testing - Hep b and c
CXR if TB/pneumonia symptoms
what are the 3 aspects to management
psychological and emotional support
HIV treatment
primary prophylaxis
what is HAART usually
a combination of 3 drugs from 2 different classes. often 2 NRTIs and 1 NNRTI
what is the goal of HART
to inhibit viral replication and so decrease viral load and for CD4 count to increase –> reduces immunocompromise and patient wont have as bad symptoms??
what is the single most importnat thing in terms of preventing drug resistance and why
adherence to treatment
if virus continues to replicate whilst person is still sometimes taking HAART, it can promote the selection of HIV strains with drug resistant mutations
if this gets out and is spread to other people - decreased ART effectiveness
what is the 2nd most important thing to prevent drug resistance
combination therapy
do people experience side effects on ARTs?
most people have diarrhoea
lots of other side effects
what are the 4 main targets of HIV drugs
and which one is the most commonly used
NRTIs and NNRTIs
is HIV infection always transmissible
no, if someone has an undetectable viral load on ART they cannot transmit virus
can you take ART during rpegnancy
yes
can you have a vaginal delivery without transmitting HIV to baby?
yes is UVL and there are no obstretric complications
will pregnancy mother transmit HIV to baby?
no, not if UVl and procedures followed correctly
giving birth and having HIV
vaginal delivery is fine if UVL and no obstretric complications
if DVL >50 - C section with Prep (Zidovudine started 4 hours before)
is anything given to the baby after it has been born?
yes, gets PEP - start within 4 hours of delivery and continue for 4 weeks
single drug if UVL and combination if DVL/high risk
also do regular blood tests
can you breastfeed with HIV
no - exclusive formula feeding
give 3 options for sero discordant couples
- treatment as prevention ± condomless sex during ovulation period
- HIV PrEP for partner
remember, there is no risk of transmission with an UVL
does PrEP work?
yes, it has an 86% risk reduction
which drugs are used for PrEP
Tuvuda - a combination of 2 NRTIs
who gets PreP
- high risk factors
- HIV positive partner with DVL
- MSM/transwoman
- UPAI ≥ 2 partners in 12/12 and likely to do so again in next 3/12
- Confirmed bacterial rectal STI in last 12/12
what are the 5 conditions for PrEP
- >16
- HIV negative
- can commit to 3 monthly follow up
- Willing to stop if eligibility and criteria no longer apply
- Resident in Scotland
what does PEP involve
3 ARV taken within 72 hours - around 80% effectiveness
