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
Hep B Transmission?
DNA virus
Parenteral
Vertical
Sexual- high risk amonst MSM
Features of Hep B
Incubation period 6 week to 6 months
Infants and children usually have asymptomatic acute infection—> much more likely to become chronic
- Usally asymptomatic
- Can include fever, jaundice and elevated liver transaminases.
Complications of HEp B
Acute liver failure
Mortality in <1% acute cases
chronic hepatitis (5-10%). ‘Ground-glass’ hepatocytes may be seen on light microscopy
fulminant liver failure (1%)
hepatocellular carcinoma
glomerulonephritis
polyarteritis nodosa
cryoglobulinaemia
Hep B serology?
Surface antigen- tells you if pt has hep B
Core ab- have they ever been exposed to Hep B
Surface ab- are they immune?
Management of Hep B?
Notifiable
Acute infection usually self- limiting- refer to infectious diseases
Refer peristent infection o hepatolgist
Screen for other STIs/ BBI and hep invariants
Vavvinate against hep A
Treatment depends on number of factors incl- age LFTs, viral load, co- infection, biopsy findings
Treatment options of Hep B
- Pegylated interferon-alpha used to be the only treatment available –> reduces viral replication in up to 30% of chronic carriers.
- A better response is predicted by being female, < 50 years old, low HBV DNA levels, non-Asian, HIV negative, high degree of inflammation on liver biopsy
- Anti-virals e.g. tenofovir, entecavir and telbivudine to supress viral load
How to manage needlestick injury?
First aid measures- wash and encourage to bleed
Inform senior
Risk assessment with occupation health- may need HIV post- exposure prophylaxis, may need HBV booster +/- HBIG within 48 hours
What is Syphilis?
STI caused by spirochaete Treponema pallidum
Infection is characterised by primary, secondary and tertiary stages.
Incubation is between 9-90 days
Primary features of syphilis?
Chancre- painless ulcer at the site of sexual contact
Local non-tender lymphadenopathy
often not seen in women, the lesion may be on the cervix
Secondary features of syphilis?
Systemic symptoms: fevers, lymphadenopathy
Rash on trunk, palms and soles
Buccal ‘snail track’ unlcers
Conylomata lata (painless, warty lesions on the genitalia)
Tertiary features of syphilis?
Gummas (granulomatous lesions of the skin and bones)
Ascending aortic aneurysms
General paralysis of the insane
Tabes dorsalis (slow degneration of the nerve cells and nerve fibres that carry sensory info to the brain)
Tertiary features of syphilis?
Gummas (granulomatous lesions of the skin and bones)
Ascending aortic aneurysms
General paralysis of the insane
Tabes dorsalis (slow degneration of the nerve cells and nerve fibres that carry sensory info to the brain)
Argyll- Robertson pupil
Features of congenital syphilis?
Blunted upper incisor teeth (Hutchinson’s teeth), mulberry molars
Rhagades (linear scars at the angle of the mouth)
Keratitis
Saber shins
Saddle nose
Deafness
How do you test for syphilis?
Serological tests can be divided into 2:
NON-TREPONEMAL TESTS:
- not specific for syphilis
-based upon reactivity of serum from infected pts to a cardiolipin- cholesterol-lecithin antigen and assesses quantity of antibodies produced
-Becomes negative after treatment
TREPONEMAL-SPECIFIC TESTS:
-More complex and expensive but more specific for syphilis
-qualitative- ‘reactive’ or ‘non-reactive’
-e.g. TP-EIA, TPHA
What can cause false positives in non-treponemal tests?
Pregnancy
SLE, anti-phospholipid syndrome
TB
Leprosy
Malaria
HIV
What would a positive test result look like for active syphilis?
Positive non-treponemal test + positive treponemal test
A patient has a positive non-treponemal test and negative treponemal test, what is your ddx?
Consistent with false-positive syphilis e.g. pregnancy
A patient has a negative non-treponemal test for syphilis and a postivit treponemal test for syphilis, what is your ddx?
Consistent with successfully treated syphilis
A pregnant lady tests positive for HIV. What steps do you take to reduce the likelihood of vertical transmission?
1) check viral load- we would like it to be undetectable. If she is not already on ART, start her on it
2) If her viral load is NOT undetectable , c-section needs to be arranges
3) Advise her, no matter her viral load, NOT to breastfeed
from ILOs
What are risk factors for HIV?
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- current or former partner with HIV
- from an area with high HIV prevalence
- are men who have sex with men (msm)
- are female sexual contacts of MSM
- transwomen
- have had multiple sexual partners, engage in high risk sex like chemsex, or have hx of STIs
- hx of IV drug use
- are current or previous sex workers
- have been raped
- have had blood transfusions, transplants, or other risk-prone procedures in countries without rigorous procedures for HIV screening
- occupational exposure such as needlestick injury
How should you manage a patient with a new diagnosis of HIV?
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If the person is well and does not need an urgent admission:
- discuss whether they prefer to be treated
- refer urgently to a specialist HIV clinic, to be seen preferably within 48 hours and at the latest within 2 weeks of testing positive.
- give written details of any appts arranged
- advise on sources of info and support
- advise on risk reduction strategies - safer sex, local services for IV drug users
- arrange follow up in a few days
What is the HIV window period?
The window period for an HIV test refers to the time between HIV exposure and when a test can detect HIV in your body. The window period depends on the type of HIV test used.
What is the window period for different HIV tests?
Describe a negative HIV test result
cdc website
A negative result doesn’t necessarily mean that you don’t have HIV. That’s because of the window period — the time between HIV exposure and when a test can detect HIV in your body.
- If you get an HIV test after a potential HIV exposure and the result is negative, get tested again after the window period for the test you took.
- If you test again after the window period, have no possible HIV exposure during that time, and the result is negative, you do not have HIV.
Describe a positive HIV test result
cdc website
If you use any type of antibody test and have a positive result, you will need a follow-up test to confirm your results.
- If you test in a community program or take an HIV self-test and it’s positive, you should go to a health care provider for follow-up testing.
- If you test in a health care setting or a lab and it’s positive, the lab will conduct the follow-up testing, usually on the same blood sample as the first test.
If the follow-up test is also positive, it means you have HIV.
How can HIV be transmitted?
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- In a person infected with HIV, the virus is present in cell-containing bodily fluids, such as blood, semen, vaginal secretions, breast milk, amniotic fluid, pleural effusions, and cerebrospinal fluid.
Infected body fluids:
* sexual activity
* vertically from mother to child
* by inoculation - a needle, blood product
