Infectious Disease #2 Flashcards
HIV Screening Recommendations:
All adults ages 18-64 (once in lifetime)
+ risk factors (yearly)
Pregnant women (once)
Pregnant women- high risk (2nd test in 3rd trimester)
Newborns (if mother is HIV + or high risk)
*30% transmission from breast feeding **
HIV risk factors?
Homosexual males Bisexual males Women with at-risk male partner Women with multiple male partners IV drug abusers Blood transfusions (high risk areas) Infants of HIV + mothers or high-risk
Early detection is key for?
Antiretroviral therapy
Appropriate immunizations
Prophylactic antibiotics
HIV screening tests?
HIV-1 p24 antigen HIV-1 antibody HIV-2 antibody HIV-1/2 antibody HIV-1/2 Ab/Ag Rapid HIV-1/2 Ab
HIV confirmation tests?
WB HIV-1 Ab WB HIV-2 Ab Immunoblot-HIV-2 Ab IFA HIV-1 Ab HIV RNA NAAT (qualitative testing)
HIV rapid tests?
Urine or saliva
*low risk that wants a screening **
Which HIV test detects the viral protein p24 in blood?
p24 direct serologic antigen assay
In the p24 test, how early is the infection detectable? and it is detectable before antibody ______________?
16 days after infection
seroconversion
- you cant detect HIV for up to three months b/c we have not ABS to it yet because it is hiding in the CD4 cells **
4th generation enzyme-linked immunoassay target of detection and days to positivity?
IgM and IgG Abx and p24 antigen
15-20 days
HIV _________ test uses PCR to replicate a very small amount of HIV RNA to a detectable amount
HIV viral load test
HIV diagnostic testing algorithm?
4th gen. HIV-1/2 immunoassay
then,
type the HIVm( is it 1 or 2)
then,
RNA testing
Determines “amount” of HIV in serum?
HIV RNA (quantitative)
HIV RNA aids in?
Marker for prognosis
Disease progression
Response to treatment
Indication for treatment
Indicates course of disease more accurately than any other test
HIV RNA is extremely sensitive to < __ copies/ml
50
HIV RNA determines baseline viral load with _ measurements - weeks apart?
2 measurements
2-4 weeks apart
What are HIV Resistance Assays?
Assess viral strains (genotyping)
Useful in selecting therapies
Useful if patient is failing therapy
Aspergillosis organism?
Aspergillus fumigatus
- affects lungs sinuses and can go into the brain = it is inhaled
- *
- most of us have an immunity towards it already but AIDS and chemo patients and people with liver and organs transplant patients can become colonized with this.
- *
Aspergillosis Tests?
PCR form tissue biopsy
Galactomannan
Fungal Ab
ELISA detecting molecule in cell wall of the fungus for Aspergillosis testing?
Galactomannan
beta-D-glucan?
fungal ABS for fungal Ab test
What Aspergillosis test is not highly reliable, not specific and can use blood and CSF samples?
Fungal Ab test
- “not good first line, or we do this first” it depends on the patient severe or not severe?**
- a lot of these patients get thrombocytopenia so careful not to make them bleed if your are doing a biopsy if they have the condition **
Candidiasis is a ________ dx?
clinical
what do you see on a KOH prep with Candidiasis?
yeast and spores - hyphae
Candidiasis ?
Clinical diagnosis KOH prep - yeast and spores ( hyphae) Vaginal pathogens probe (microscopy) Blood culture revealing fungemia Beta-D-glucan testing
diabetics and chemo patients
Coccidiomycosis labs?
ELISA for IgM Ab early in the disease process
CSF
a patient has Coccidiomycosis and you read of their labs that they are having “persistent rising IgG complement fixation titers”, what does this suggest?
disseminated disease
Coccidiomycosis and CSF sample?
Complement fixing Ab (>90% of cases)
IgG titers keep getting higher and higher
*meningitis? we can see coccidia in the CSF as well**
Coccidiomycosis is common in patients with what?
HIV
Cryptococcis is common from?
pigeon droppings inhaled
what is the most common cause of fungal meningitis ?
Cryptococcis
How do you culture PULMONIC Cryptococcis?
Culture of resp secretions or pleural fluid
Cryptococcosis CSF culture results?
Gram stain shows budding encapsulated fungi
+ capsular polysaccharide antigen is diagnostic - looking for the antigen in the CSF - what Indian stain is it?
Histoplasmosis comes from?
bird and bat droppings
Geographic location for Histoplasmosis?
found in the Ohio river valley and mississippi river valley
What is Histoplasmosis ?
acute pulmonary infection that lasts one week to six months
Histoplasmosis CXR?
miliary infiltrates
Histoplasmosis Labs: Ferritin 9?
elevated - maybe liver involvement
Histoplasmosis Labs: CBC w/ diff?
Pancytopenia with disseminated forms
- can affect bone marrow production cells and we can get pancytopenia
- *
Histoplasmosis Labs: UA assay + serum polysaccharide. antigen assay (83% sensitive) can be used for what??
Urine antigen assay can be used to follow treatment
- we treat the patient and we see that the titers are decreased confirming treatment is working?**
Pneumocystic organism?
Pneumocystis jirovecii
Culture of Pneumocystis jirovecii by?
BAL
Treatment for Pneumocystis jirovecii?
bactrim
- we treat it with bactrim and we culture it from bronchial lavage = the X-ray looks worse than the patient is**
Parvovirus B19 AKA?
slap check disease
Parvovirus B19 serum test indications?
organ donors
children with vague symptoms
Parvovirus B19 symptoms (vague?)?
fever
rash
arthralgias
coryza
- we do not usually test for it cause it is a clinical diagnosis **
Parvovirus fetal infection test?
B19 DNA in amniotic fluid
Parvovirus ELISA of IFA: latent infection?
IgG
Parvovirus ELISA of IFA: acute infection?
IgM
Mumps amylase test result?
elevated
Munps shows elevated what?
amylase and serum IgM and 4-fold rise in IgG titers
If a kid has mumps, what are the two most common complications?
septic meningitis or vesticular involvement - orkytis
Rubella AKA?
german measles
Rubella test results?
4 fold rise in IgG titers
Elevated IgM titer
What are other viral infections that can give a rubella test a FALSE positive ?
EBV
CMV - cytomegalovirus
Parvovirus
RF
*concerning infection with pregnant woman = congenital defects **
Measles test results?
Elevated IgM
4 fold rise in IgG titers
What is Measles?
viral illness mostly in children
we vaccine against it
not really any severe complications from it
Measles rash progression?
rash first appears on the neck and face
then,
spreads quickly to cover entire body
Rabies testing?
DFA of skin biopsy
Viral isolation from CSF and Saliva
*almost 100% fatal 100% of the time**
Rabies treatment?
we put rabies IgG ( rabies immunoglobulin) around the bite, and we give them rabies shot , wash the bite, and mark sure the tetanus is up to date……on opposite side of the body you give them the booster ( how ever many days until the booster course is completed) - it is very import to vaccine people that are at high risk.
West Nile Virus testing?
Serum or CSF
West Nile Virus indications?
Flu like sxs in an area that WNV is common
Screening donated blood
West Nile Virus vector?
mosquito
What is West Nile Virus? background?
RNA virus (Flavavirus family)
Transmitted by household mosquitoes
West Nile Virus initial test?
ELISA or IFA
What will ELISA show with WNV infection?
IgM (10 days after sxs start)
WNV confirmatory test?
2nd IgM 3-4 weeks later
WNV RNA
IgM in CSF - if meningitis like symptoms
Interfering factors with WNV?
Other flavavirus infections (Japanese encephalitis)
Normal WNV results?
No Ab to WNV
Indication to test for HSV (herpes)?
Identify acute herpetic infections
Pregnant women (deliver 6-8 weeks?)
Immunocompromised patients - HIV/AIDS at higher risk of infection
*we talk about zoster (shingles) and varicella ( chicken pox) and genital herpes = all in the herpes family**
HSV GS testing and result?
Viral Culture is GS
90% accuracy
sensitivity 50%
specificity near 100%
more accurate picture of the disease process going on
*unroof the vesicle and get some of the fluid = better accurate result **
HSV serologic testing?
more disseminated disease
ELISA or IFA - measuring IgG
What does ELISA for HSV 9 herpes) differentiate?
differentiates between Type 1 and Type 2 or varicella or zoster
- no hx of blisters of sores and the have a positive HSV1 result then it is not a great prognostic tool **
HSV PCR is used on?
CSF
Get _____________ results and then order PCR.
preliminary
