HIV Flashcards
what is HIV?
RNA retrovirus
which type of HIV is responsible for the global epidemic?
HIV-1 group M
life cycle of HIV
- Two strands of RNA with GP120 and GP41 antigens that bind to Th cells CD4+ receptor
- RNA enters the cell and is converted to DNA and integrated into the host cell
- Creates viral proteins and assembles another virus every 6-12 hour
how long does it take HIV to establish infection?
within 3 days of entry so 72 hours for PEPSE
where is the CD4+ receptor found?
Th cells
dendrites
macrophages
microglia
what is the CD4+ receptor essential in?
recognition of MHC-II APCs
activation of B cells
activation of Tc (CD8+) with cytokine release
what is a normal CD4+ count?
500-1,600 cells/mm3
what CD4+ count is there a high risk of opportunistic infections?
<200 cells/mm3
presentation of primary HIV
2-4 weeks later fever rash (maculopapular) myalgia pharyngitis headache aseptic meningitis can be asymptomatic
what is the risk in primary HIV?
very high risk of transmission
what is late stage HIV?
AIDS
describe the cascade to AIDs?
HIV > immunosuppression > opportunistic infections/ cancer > AIDs
at risk groups
MSM
heterosexuals aged 15-44
black African
PWIDs
diagnosis
viral RNA, antigen p 24 or antibody
rapid= finger prick or saliva (20-30 minutes)
why can you not reply on a negative Ab in first 6 weeks?
3 month window period (different people make Ab at different rates)
management of HIV
start therapy at all CD4 counts
HAART= combination of 3 drugs from at least 2 drug classes
partner notification
side effects of HAART
GI
drug interactions
co-infections
polypharmacy
management of HIV in pregnancy
C/S
vaginal birth if undetectable load
prevention of neonatal HIV
zidovudine infusion given 4 hours prior to C/S
prevention methods
condoms regular testing PrEP PEP ART needle exchange neonate prophylaxis
what is PEP consist of?
4 weeks of tenofovir/ emtricitabcine and raltegravir
examples of opportunistic infections
- pneumocystis pneumonia (PCP)
- TB
- cerebral toxoplasmosis
- CMV
- HIV dementia
- prgressive multifocal leukoencephalopathy (PML)
- skin infections that are recurrent, extensive and resistant
- Slim’s disease
- cancers
what causes PCP?
pneumocystitis jiroveci
presentation of PCP
SOB
dry cough
CD4 <200
diagnosis of PCP
CXR
BAL
immunofluorescence +/- PCR
management of PCP
co-trimoxazole
what causes cerebral toxoplasmosis?
toxoplasma gondii
what is cerebral toxoplasmosis?
reactivation of latent infection produces cerebral abscesses and chorioretinitis
presentation of cerebral toxoplasmosis
headache fever focal neurology seizures reduced consciousness raised ICP CD4 <150
presentation of CMV
reduced visual acuity floaters abdominal pain PR bleeding CD4 <50
when is ophthalmic screening carried out?
all those with CD4 <50
what causes progressive multifocal leukoencephalopathy PML?
JC virus
presentation of PML?
CD4 <100 rapidly progressive focal neurology confusion personality change MS-type picture
what is Slim’s disease?
HIV-related cachexia
which cancers are related to AIDS?
Kaposi’s sarcoma (HHV8)
NHL (EBV)
cervical cancer (HPV)
