HIV Flashcards
What type of virus is HIV
Single stranded enveloped RNA virus (retrovirus)
Family: retroviridae
Genus: Lentivirus
Two types of HIV
HIV-1 (most common), HIV-2 (West Africa, more indolent, less vertical transmission, intrinsic resistance)
How does HIV cause disease
Destroys CD4 helper lymphocytes, creating acquired immunodeficiency
Most common mode of transmission of HIV in paediatrics
Vertical transmission (Mother to baby), highest risk of transmission is intrapartum
HIV clinical presentation
FTT, unexplained prolonged fever, chronic diarrhoea, opportunistic infections, lymphadenopathy, splenomegaly, persistent oral/napkin candidiasis
Acute retroviral syndrome
Adolescents; fever, malaise, lymphadenopathy, rash 7 - 14 days post infection (Glandular fever type illness)
Laboratory criteria for HIV diagnosis <18 months
Positive HIV NAT, HIV DNA or HIV RNA. x2 positive tests. Serology not useful, as maternal antibodies transfer
Laboratory criteria for HIV diagnosis >18 months
Positive HIV antigen/antibody test (fourth generation tests) which can detect HIV-1/HIV-2 Ab and HIV-1 p24 antigen (can be detected as early as 10 - 14 days after infection. PLUS positive on different supplemental test (Western blot, HIV-1/2 differentiation immunoassay)
CAR T-Cell therapy and HIV
HIV tests can be false positive in patients who have had this, as same lentivirus can be used as viral vector for CAR T-Cell
Four main ART classes
NRTI (Nucleoside Reverse Transcriptase Inhibitor) NNRT (Non Nucleoside Reverse Transcriptase Inhibitor), ISTI (Integrase Inhibitor), PI (Protease Inhibitor)
Treatment for Paediatric HIV
2 NRTIs + third drug (NNRTI, PI or ISTI) Most evidence from Odyssey Trial for ISTI
NRTI examples
Zidovudine, Tenofovir, Lamivudine, Abacavir
NNRTI examples
Nevirapine
ISTI examples
Raltegravir, Dolutegravir
PI examples
Lopinavir/Ritonavir, Atazanavir
Side effects of NRTI
Lactic acidosis, mitochondrial toxicity, Zidovudine causes anaemia, and Tenofovir causes renal tubular dysfunction. Abacavir has hypersensitivity with HLA B5701
Side effects of NNRTI
Rash, hepatitis, SJS within 6 weeks
Side effects of PI
Lipodystrophy, hyperlipidemia, diabetes CYP3A4 metabolism (drug interactions)
Side effects of INSTI
Insomnia, mood changes
What percentage of HIV in kids is acquired through vertical transmission?
95%
What is the risk of HIV vertical transmission without intervention?
25 - 45%
When is highest risk of vertical transmission and what percentage?
60-70%, at delivery
Maternal risk factors for vertical transmission
High viral load, low CD4 count, STIs, placental infection
Delivery risks for vertical transmission
Prematurity, LBW. PROM. vaginal birth assisted delivery, episiotomy, ARM, chorio
What is the risk of infection in utero?
30 - 40%
What intrapartum interventions can be instituted if high maternal viral load at 36 weeks?
Intrapartum antivirals, elective caesarean at 38 - 39 weeks gestation
What type of feeding recommended for HIV positive mothers
Formula/donor EBM. RIsk of breast feeding transmission 5 - 20%, and with good ART suppression and supported breastfeeding reduces to <1% but not zero
Risk factors for post partum transmission
Detectable viral load, longer feeding, mixed feeding, neonatal mouth or breast inflammation
Neonatal post exposure prophylaxis
Commenced <4 hours after birth, 2 weeks for very low risk, 4 weeks for low to high risk
When to start PCP prophylaxis
HIV PCR positive at any time or infant confirmed to have HIV.
What is used for PCP prophylaxis and from what age
Cotrimoxazole, from 1 month age
What is U = U
Undetectable = Untransmissible for sexual transmission, but doesn’t prevent other STIs so still need to use barrier protection
Definition of undetectable viral load
VL <200 copies/mL for >6 months
What is PREP
Pre-exposure prophylaxis in high risk, HIV negative populations. Daily ART given to reduced risk of transmission. 90% effective
What is nPEP
Non occupational post exposure prophylaxis. Risk of HIV transmission = risk of HIV viraemia in source x exposure activity risk
When to start nPEP and duration
Start <72 hours, duration 28 days, then test baseline serology then 3 months
Which age group is HIV related mortality rising>
Adolescents. Poorer ART adherence.