GUM: HIV & AIDs and Blood borne infections Flashcards
HIV transmission?
Sex
Paraenteral
Vertical transmission
How does HIV affect body?
Attack CD4 T cells and if untreated causes progressive loss of immune function–> increases risk of oppurtunistic infection (life threatening) and malignancy
Epidemiology of HIV?
End of 2021:
38.4 million people living with HIV
2/3 are in in WHO African region
What is HIV seroconversion?
When in infected- HIV starts to multiply–> CD4 count drops (HIV seroconverison)- first month after infection
Then after get into asymptomatic stage- CD4 count slightly recovers–> but not normal, may get symptoms, progressively worse e.g. previous hx of acne may recur (if they’re untreated and can progress into AIDs at around 10 years)
Features of HIV seroconversion?
sore throat
lymphadenopathy
malaise, myalgia, arthralgia
diarrhoea
maculopapular rash
mouth ulcers
rarely meningoencephalitis
How to diagnose HIV seroconversion?
antibodies to HIV may not be present
HIV PCR and p24 antigen tests can confirm diagnosis
Disease pts may get with AIDS and what CD4 count?
Below 50 cells/ mm3
CMV retinitis
Brain malignancies
HIV Dementia
Mycobacterium avium-intracellulare infection
Testing for HIV?
Blood test- 4th generation combo assay
* Detects Anti-HIV antibodies
* Detects P24 antigen (viral core protein)
* Window period ( time it takes for a postive test to show) + 45 days- if someone presents before this, advise them to come back at the end of this period
- if postivie- confirmatory tests- immunoblot
- RNA detection by PCR for ‘viral load’ - burden of HIV and helps in monitoring treatment response
Aim of HIV treatment?
Undectable viral load- less chance of mutating into resistant strain
What tests do you do as HIV follow up?
CD4 count
HIV viral load
HIV resistance testing- some may be resistance to certain treatment
FBC
U&Es- tx may affect kidneys
LFT- tx may affect liver
Bone profile
Physical assessment
Fundoscopy
Urine dip
Other STIs and BBV
TB screening
HIV treatment?
Triple Anti-retroviral therapy
3 drugs- typically 2 NRTI ( Nucleoside analogue reverse transcriptase inhibitors) plus 3rd agent
Some newer, 2 drug regimens emerging, many one pill daily
Long acting injectable agents recently approved 2021
Different treatment classes for HIV?
Entry inhibitors
maraviroc (binds to CCR5, preventing an interaction with gp41), enfuvirtide (binds to gp41, also known as a ‘fusion inhibitor’)
prevent HIV-1 from entering and infecting immune cells
Nucleoside analogue reverse transcriptase inhibitors (NRTI)
examples: zidovudine (AZT), abacavir, emtricitabine, didanosine, lamivudine, stavudine, zalcitabine, tenofovir
general NRTI side-effects: peripheral neuropathy
tenofovir: used in BHIVAs two recommended regime NRTI. Adverse effects include renal impairment and ostesoporosis
zidovudine: anaemia, myopathy, black nails
didanosine: pancreatitis
Non-nucleoside reverse transcriptase inhibitors (NNRTI)
examples: nevirapine, efavirenz
side-effects: P450 enzyme interaction (nevirapine induces), rashes
Protease inhibitors (PI)
examples: indinavir, nelfinavir, ritonavir, saquinavir
side-effects: diabetes, hyperlipidaemia, buffalo hump, central obesity, P450 enzyme inhibition
indinavir: renal stones, asymptomatic hyperbilirubinaemia
ritonavir: a potent inhibitor of the P450 system
Integrase inhibitors
block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell
examples: raltegravir, elvitegravir, dolutegravir
What to ask HIV pts if they present to you?
What medications are you taking
How long have you been taking it
Have you missed any?
Do you take it every day?
Any other medication s
Previous treatments/ failures (may indicate resistance)
HIV prevention?
Condoms
Screening and regular testing
Treatment as prevention- undetectable= untransmissable, if been undectable to 6 months- 0 risk to pass on sexually
Post- exposure prophylaxis - within 72 hours of high risk exposure, Truvada + Raltegravir for 28 hours, available via A&E or sexual health services
Pre-Exposure prophylaxis- high risk patients eligible, truvada either daily or event- base, reduced accquistion of HIV by AT LEAST 86%
Testing for Hep C?
Anti-HCV serology used for initial screening
Marks current or past infection
Becomes postivie 4-10 weeks after exposure- antibody provides incomplete protection, reinfection possible
Next test is HCV RNA- to distinguish past infection
Hep C genotype used to guide treatment
Hep C Advice for patients?
Curable
Check for other hep infections and vaccinate against Hep C
Cannot donate blood
Discuss routes of transmission and risk reduction
STI screen
Risk of liver malignancy