HIV Flashcards

1
Q

pre-exposure prophylaxis (PrEP) eligibility

A

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

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2
Q

post exposure prophylaxis hep B

A

HBV vaccine booster - within 7 days

Immunoglobulin - for vaccine non-responders

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3
Q

HIV post exposure prophylaxis

A

3 antiretrovirals for 28days (4wks)
start within 72hrs
testing at 12weeks following completion

80% reduced risk of transmission

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4
Q

management of non-consensual sex

A

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

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5
Q

HIV vs AIDs

A

AIDs = acquired immunodeficiency syndrome - late stage of HIV
- occurs as person becomes immunodeficient
- leads to opportunistic infections + AIDS definign illnesses

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6
Q

HIV types

A

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

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7
Q

transmission of HIV

A

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

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8
Q

pathophysio of HIV

A

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

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9
Q

effect of HIV on immune response

A

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

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10
Q

CD4 parameters

A

normal = 500-1600

highest risk of opportunistic infections = <200

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11
Q

HIV screening

A

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

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12
Q

taking an HIV test

A

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

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13
Q

mode of delivery in HIV positive mums

A

vagina if viral load <50 copies/ml at 36weeks

–> other wise C-section

NEVER breastfeed

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14
Q

HIV seroconversion

A

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

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15
Q

screening + diagnostic test for HIV

A

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

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16
Q

when should HIV testing for asymptomatic patients be done?

A

at 4 weeks after possible exposure

after inital neg result in asymptomatic patient, offer repeat test at 12wks

17
Q

highly active anti-retroviral therapy (HAART)

A

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

18
Q

key to preventing drug resistance in HIV therapy

A

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

19
Q

HIV management

A

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

20
Q

notable side effect of antiretroviral therapy

A

potent liver enzyme inducers (PI, NNRTIs)

21
Q

side effects of NRTIs

A

general side effects = peripheral neuropathy
o Tenovir – renal impairment, osteoporosis
o Zidovudine – anaemia, myopathy, black nails
o Didanosine – pancreatitis

22
Q

aids defining illnesses

A

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

23
Q

examples of aids defining illnesses

A

kaposis sarcome
pneumocystis jivrovecci pneumonia (PCP)
CMV
candidiasis - oesophageal or bronchial
lymphomas
tuberculosis

24
Q

pneumocytis jirovecii pneumonia presentation

A

CD4 threshold = <200

insidious onset
SOB
dry cough
exercise oxygenation desaturation **

25
pneumocytis jirovecii pneumonia investigations
CXR = interstitial infiltrates, retiiculonodular markings, may be normal diagnosis = BAL (bronchial alveolar lavage) + immunoflurorescence +/- PCR (silver stain shows cysts)
26
pneumocytis jirovecii pneumonia treatment
co-trimoxazole - high dose prophylaxis = low dose co-trimoxazole --> anyone with CD4 <200
27
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)
28
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
29
HIV + cerebral toxoplasmosis
organism = toxoplasma gondii CD4 threshold = <150 reactication of latent infection - multiple abscesses, chorioretinitis presentation = headache, fever, seizures, raised ICP
30
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
31
HIV assoc neurocognitive impairment
organism = HIV-1 Cd4 threshold = incidence increases with decreased CD4 presentation = reduced short term memory +/- motor dysfunction
32
progressive multifocal leukoencephalopathy (PML)
organism = JC virus (reactivation) CD4 threshold = <100 presentation - rapidly progressing - focal neurology - confusion - personality change
33
AIDs related cancers
Kaposis sarcoma non-hodgkins lymphoma cervical cancer
34
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