Path: HIV & Associated Inf Flashcards
What are the features of acute retroviral syndrome?
3-6 wks after inf, resolves in 2-4 weeks
seeding of lymphoid organs, high virus replication
mono-like syndrome: rash, cervical lymphadenopathy, N/V
What laboratory testing is done for HIV?
serology:
screening - enzyme immunoassays for Abs and p24
confirmatory - western blot and immunofluorescence
differentiation assay - HIV-1 vs. HIV-2
molecular assays
What are the basics of enzyme immunoassays (EIA) for testing in HIV?
Abs/Ags appear 2-8 wks following inf
screening test, positives followed by confirmatory or differentiation assay
What are the basics of immunofluorescence assays for testing in HIV?
HIV inf cells fixed to slide, add pt serum and incubate
wash and add anti-human Ab w fluorescent tag
look for fluorescing cells
only detects HIV-1, first generation
What are the basics of the HIV-1/HIV-2 differentiation assay?
EIA that detects Abs, second generation
cheaper, quicker and easier than WB
What are the molecular assays used for testing in HIV?
PCR: qualitative (diagnosis but not first line test, screening for blood products), quantitative (predict viral load and progression of dz, monitor response to Tx)
What are the basics of the HIV genome?
gag region - forms p17 and p24
pol region - encodes protease, integrase and reverse transcriptase
env gene - encodes gp120 and gp41
What are the basics of the WB used for testing in HIV?
technically challenging
detects Abs to gp120, gp41, p24
first generation - only detects IgG - can lag up to 3 wks and produce false negatives
What is the basic testing algorithm for HIV?
start with fourth generation assay
confirm + w rapid IgG immunoassay (2nd) that differentiations HIV-1 from HIV-2
negative or indeterminate tested for HIV-1 RNA
negative, further eval needed
What is the testing algorithm for HIV at Parkland?
3rd gen test as screen
+ confirmed w IFA
negative/indeterminate IFA send to reference lab for WB or HIV-2
What are the basics of CMV inf in HIV?
primary asymptomatic or mono-like, latency in WBCs, reactivation in immunocompromised
retinitis, colitis, esophagitis, pneumonitis, CNS
dx by biopsy or quantitative PCR on blood, owl’s eye nuclear inclusions
What are the features of the CNS dz seen in pts w HIV?
aseptic meningitis w/i 1-2 wks of seroconversion - CSF has lymphocytes, protein, normal glucose
encephalopathy
Positive stain by mucicarmine indicates what pathogen?
crypto
What are the features of PML in pts with HIV?
JC polyoma virus (DNA)
infects oligodendroglial cells
multifocal demyelination, global encephalopathy, variable focal neurologic deficits
dx by imaging, PCR on CSF, biopsy, white matter has granular appearance grossly
What syndromes can CMV cause in HIV?
encephalitis, ventriculitis/choroid plexus, radiculoneuritis (lower cord and roots)
