HIV Flashcards
pre-exposure prophylaxis (PrEP) eligibility
MSM condomless anal sex with 2+ partners in last year + likely in next 3months
rectal bacterial STI in last year
ongoing sexual contact with someone with HIV VL >50
OR 2 sexxual health clinicians agree similar risk above
post exposure prophylaxis hep B
HBV vaccine booster - within 7 days
Immunoglobulin - for vaccine non-responders
HIV post exposure prophylaxis
3 antiretrovirals for 28days (4wks)
start within 72hrs
testing at 12weeks following completion
80% reduced risk of transmission
management of non-consensual sex
recent <7days
- immediate safety
- forensic if appropriate/wished
- PEPSE for HBV (+HIV) if appropriate)
- Mx physical injuries, STI + contraceptive care as needed
later >7days
- safeguarding
- HBV if within 6wks
- assess coping / ongoing psychological impact
**autonomy important
HIV vs AIDs
AIDs = acquired immunodeficiency syndrome - late stage of HIV
- occurs as person becomes immunodeficient
- leads to opportunistic infections + AIDS definign illnesses
HIV types
HIV-1 = commonest
HIV-2 = rare outside of west africa
takes up to 72hrs from exposure to establish itself as an infection
after infection is established there is rapid replication + dissemination of virus to reservoir sites
transmission of HIV
oral, anal, vaginal sex - 79%
(factors increasing transmission - anoreceptive sex, trauma, genital ulceration, concurrent STI)
mother to child at any stage of pregnancy, birth, or breastfeeding
muscous membrane, blood or open wound exposure to infected blood/bodily fluids
- sharing needles, blood splashed in eye
pathophysio of HIV
RNA retrovirus
virus enters + destroys CD4 T-helper cells of immune system (langerhans + dendritis)
- transport to regional lymph nodes
- infection established within 3 days of entry
- dissemination of vieus
initial seroconversion flu-like illness within 2-4wks of infection
then infection asymptomatic until condition progresses to immune deficiency
rapid replication in very early + very late infection - new generation every 6-12hrs
effect of HIV on immune response
reduce circulating CD4
reduce proliferation of CD4
reduce CD8 cytotoxic activation - dysregulated expression of cytokines
reduction in antibody class switching - reduce affinity of antibodies produced
chronic immune activation
–> all increase susceptibility to infections
CD4 parameters
normal = 500-1600
highest risk of opportunistic infections = <200
HIV screening
many dont know, high risk should be tested
can take up to 3month to develop antibodies - test can be neg in this time
**patients need consent for test
at risk = MSM, female partner of MSM, black africans, prisoners, trans women, PWID, partners of people living with HIV, Sub-Saharan Africa, Caribbean, Thailand, sexual partners, children iatrogenic exposure from these/other endemic areas
taking an HIV test
document consent or refusal
obtain venous sample for serology
if incapacitated
- only test if in patients best interest
- consent from relative not required
- if safe - wait till regains capacity
mode of delivery in HIV positive mums
vagina if viral load <50 copies/ml at 36weeks
–> other wise C-section
NEVER breastfeed
HIV seroconversion
typically occurs 3-12weeks after infection
increased symptomatic severity assoc with poorer long term prognosis
presents as glandular fever type illness
- sore throat
- lymphadenopathy
- diarrhoea
- maculopapular rash
- mouth ulcers
screening + diagnostic test for HIV
Combination test of -
1. Antibodies to HIV may not be seen
* Most people develop by 4-6wks but 99% by 3months
2. HIV PCR + p24 antigen can confirm diagnosis
* A viral core protein that appears early in the blood as the viral RNA levels rise
–>if positive should be repeated to confirm diagnosis
when should HIV testing for asymptomatic patients be done?
at 4 weeks after possible exposure
after inital neg result in asymptomatic patient, offer repeat test at 12wks
highly active anti-retroviral therapy (HAART)
a combination of 3 drugs from at least 2 drug classes which virus is susceptible to
Purpose
o Reduce viral load to undectable levels
o Restore immunocompetence
o Reduce morbidity + mortality
o Prevent onward transmission
key to preventing drug resistance in HIV therapy
adherence
-> the less you take medications on time everyday, the weaker the wall becomes - if the wall is too weak HIV learns to get through and becomes resistant
HIV management
Antiretroviral therapy (ART) involves a combination of at least 3 drugs, typically -
o 2 nucleoside reverse transcriptase inhibitors (NRTI)
o + either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor (NNRTI)
-> This combination both decreases viral replication + reduces risk of viral resistance emerging
ART should be started as soon as they are diagnosed
notable side effect of antiretroviral therapy
potent liver enzyme inducers (PI, NNRTIs)
side effects of NRTIs
general side effects = peripheral neuropathy
o Tenovir – renal impairment, osteoporosis
o Zidovudine – anaemia, myopathy, black nails
o Didanosine – pancreatitis
aids defining illnesses
assoc with endstage HIV, where CD4 count has dropped to a level that allows for unusual opportunistic infections + malignancies to appear
–> infections that does not normally produce disease in a healthy individual
examples of aids defining illnesses
kaposis sarcome
pneumocystis jivrovecci pneumonia (PCP)
CMV
candidiasis - oesophageal or bronchial
lymphomas
tuberculosis
pneumocytis jirovecii pneumonia presentation
CD4 threshold = <200
insidious onset
SOB
dry cough
exercise oxygenation desaturation **
pneumocytis jirovecii pneumonia investigations
CXR = interstitial infiltrates, retiiculonodular markings, may be normal
diagnosis = BAL (bronchial alveolar lavage) + immunoflurorescence +/- PCR (silver stain shows cysts)
pneumocytis jirovecii pneumonia treatment
co-trimoxazole - high dose
prophylaxis = low dose co-trimoxazole
–> anyone with CD4 <200
HIV ++ TB
usually miliary TB
sensitivity of acid fast bacilli on Ziehl-Neelsen stain reduced in individuals with HIV
gold standard = sputum culture (takes 1-3wks tho)
management of TB
Initial phase – 2 months
o Rifampicin = orange secretions, liver enzyme inducer
o Isoniazid = peripheral neuropathy
o Pyrazinamide = hyperuricaemia (causing gout)
o Ethambutol = optic neuritis
Continuations – next 4 months
o Rifampicin
o Isoniazid
- Latent = 3 months of isoniazid + rifampicin
HIV + cerebral toxoplasmosis
organism = toxoplasma gondii
CD4 threshold = <150
reactication of latent infection - multiple abscesses, chorioretinitis
presentation = headache, fever, seizures, raised ICP
cytomegalovirus + HIV
CD4 threshold = <50 *
reactivation of latent infection -> retinitis, colitis, oesophagitis
presentation = reduced visual acuity, floaters, abdo pain, diarrhoea, PR bleeding
- infected cell bodies have a “owls eye” appearance due to intranuclear inclusion bodies
ix = ophthalamic screening for individuals CD4<50
HIV assoc neurocognitive impairment
organism = HIV-1
Cd4 threshold = incidence increases with decreased CD4
presentation = reduced short term memory +/- motor dysfunction
progressive multifocal leukoencephalopathy (PML)
organism = JC virus (reactivation)
CD4 threshold = <100
presentation
- rapidly progressing
- focal neurology
- confusion
- personality change
AIDs related cancers
Kaposis sarcoma
non-hodgkins lymphoma
cervical cancer
Kaposi’s sarcome
organism = human herpes virus 8 (HHV8)
vascular tumour
presentation = purple papules/plaques on skin/mucosa - may ulcerate
- resp involvement may cause massive haemopysis + pleural effusion
