Flashcards in Day 7.2 and 7.3 Micro- Virology Deck (142):
Use for acyclovir, ganciclovir
Acyclovir = HSV, VZV, EBV
Ganciclovir = CMV
If these fail, can use foscarnet.
Have disease right now
Either recovered from dz
OR have been immunized
Indicates new dz, but this is not something that can be measured in the serum, so won't get a measurement for it on the test.
Hx of active dz (only- will NOT be positive if you have just been immunized)
What are the core HBV Ab?
IgM for early, active dz
IgG later, for chronic dz
Indicates active infection
and HIGH lvl of transmissibility
High E = High Enfectivity
eg Chronic contagious
Indicates infection but chonic, LOW transmissibility
eg Chronic low-infective
What will the HBV serologic markers show in active dz?
HBcAb + (IgM)
What will the HBV serologic markers show in the window period (equivalence zone)?
HBcAb + (IgM)
There are Ab present, but they're all bound to Ag, so nothing is detected in the assay. Confusing, but you know it bc of the IgM core Ab, which indicate a newer infection.
What will the HBV serologic markers show in a chronic, highly infective state?
HBcAb + (IgG)
Think: dz is winning!
This is the same as active dz except for the core Ab is now IgG since it's chronic.
What will the HBV serologic markers show in a chronic, low-infective state?
HBcAb + (IgG)
Will still have +surface Ag and -surf Ab bc you still have dz.
But, since it's low infective (and E is for Enfectivity, your E Ag will be neg (and E Ab pos)
What will the HBV serologic markers show in complete recovery?
HBcAb + (IgG)
Winning! All Ag's neg, all Ab's positive
What will the HBV serologic markers show in an immunized pt who has never had dz?
HBcAb - (this is the only time core will be negative, if you have Ab. other scenario is never had it and never vaccinated)
Which Hepatitis virus is a DNA virus?
Transmission of chicken pox vs shingles
Chicken pox = respiratory
Shingles = only by direct contact w active lesions. Cover them and they won't be spread.
Where does HSV1 lie dormant?
Where does HSV2 lie dormant?
S2 and S3 ganglia
Where does VZV (chicken pox and shingles) lie dormant?
Trigeminal ganglia and dorsal root ganglia
What does EBV cause?
Burkitt's lymphoma (endemic)
oral hairy leukoplakia
What can EBV look similar to? If pt is treated for wrong thing, what happens?
Looks like strep throat
If pt is given aminopenicillins (amoxicillin) for the strep, they will get a rash (and will think they are allergic to amox)
EBV + amox = rash
If the pt has mono but has a negative monospot, what is the cause?
When CMV affects AIDS pts, what are they prone to?
Pneumonia from CMV
Esophagitis from CMV
What age does roseola usu infect?
Roseola = HHV-6
What cancer can be caused by HBV and HCV?
Tumor marker for it?
Alpha feroprotein (AFP)
Main txmsn of HBV
Also parenteral (eg injection) and maternal-fetal
Main txmsn of HCV
Parenteral (IV drug users)
Also post-transfusion if blood not screened.
Rx for HCV
What causes aplastic crisis in sickle cell pts?
Which papilloma viruses cause warts? CIN?
Warts = 1, 2, 6, 11
Cervical interepithelia neoplasia = 16, 18
What is the polyoma virus? What does it cause?
JC virus, causes PML in HIV pts
PML - progressive multifocal leukoencephalopathy
What is molluscum contagiousum?
Flesh-colored dome lesions w a central dimple (on skin)
It's a poxvirus
Only DNA virus that is not double stranded?
Downey cells are the abn circulating Cytotoxic T cells (atypical lymphocytes). They have a foamy cytoplasm.
Main char- yellow fever
Hemorrhagic Dz- Black vom!
Can cause liver, renal dz
Weird tongue: red on tip and sides but white in center
Child w major diarrhea in winter months
ROTA = right out the ass
Influenza virus Ag
Hemagglutinin- promotes viral entry
Neuraminidase- promotes release of progeny viruses
Pts w influenza are at risk for bacterial superinfection from what?
S. pneumonia, H. influenza, etc
Anything that causes pneumonia
Can be fatal.
Shift vs drift
Shift = Reassortment. Worse. (Oh Shift!)
Drift = minor chg based on random mutation.
Things that cause aseptic (viral) meningitis
(they are both enteroviruses)
What is another name for measles virus?
(RUBy has measles, and is ruby red from head to toe)
(RuBELLA is visiting from Germany for 3 days)
(ROSEola is HHV-6. I want 6 roses for my birthday.)
T/F immunodeficient pts who get measles won't have a rash or Koplik spots.
The rash and spots are immune rxns, so pts w/o good immune systems won't get them.
The reactions take place in the endothelial cells of dermal capillaries.
In what direction on the body does the measles rash spread?
From head to toe (can of paint)
What congenital heart defects are caused by Rubella?
PDA and Pulmonary Artery Stenosis
ruBELLA is visiting from Germany for 3-days.
What RNA viruses cause aseptic meningitis and myocarditis?
Which polio vaccine is live attenuated?
Sabin is live-attenuated and given orally.
SalK is Killed.
How does polio cause paralysis?
Affects the motor neurons of the anterior horn.
#1 cause of fatal diarrhea in kids
What RNA virus is causes meningitis in summer months?
Echovirus, bc it is transmitted in swimming pools
Tourniquet test is for which RNA virus?
West Nile Virus: reservoir, vectors, hosts
Incidental hosts (only bc mosquitos bite them): humans, horses, dogs
West Nile virus sympt
Most people: flu-like
1/150 have severe case: meningitis (possibly w encephalitis) incl muscle weakness and flaccid paralysis bc of anterior horn involvement.
Bird to human only
URI, diarrhea, fever, pancytopenia, elevated liver enz
Rx: oseltamavir (tamiflu)
Flu + GI sympt
Rx oseltamavir or zanamivir but only in high risk or severly ill pts bc of wide spread resistance and side effects
Asthma sympt in a preemie in winter
Rx for preemies in winter months
Passive immunization w Palivizumab (monoclonal RSV Ig) monthly during winter to protect them from RSV
Also give it to infants w chronic lung dz.
Low-pitched barking cough in kid <4yo
Croup (Parainfluenza virus)
Xray may show steeple sign
T/F Ribavirin is the Rx for RSV
True... but NOT in kids.
Used in adults if RSV develops after bone marrow txplt.
What anti-viral can be used for Parkinsons?
Amantidine (historically for influenza) has side effect of releasing dopamine from nerve terminals, so can be used.
Rimantidine does not cross the BBB so it cannot be used.
First line Rx for HSV or EBV
Acyclovir (or others- Famcyclovir)
Second-line for CMV retinitis
Inhibits CMV DNA polymerase
Inhibits viral DNA polymerase when phosphorylated by viral thymidine kinase
Acyclovir, Ganciclover, Famcyclovir, Valacyclovir
What kind of virus is HIV (DNA, RNA)
It has a diploid genome (2 RNA molecules)
However, despite being RNA it has to integrate into host DNA, so Reverse Transcriptase synthesized dsDNA from the RNA, and the dsDNA integrates into the host genome w the help of DNA integrase.
What receptors does HIV bind to on host cells?
Binds to CXCR4 and CD4 on Tcells (the "T-tropic strain does this, called X4 virus)
Binds to CCR5 and CD4 on macrophages (the macrophage-tropic strain does this- called R5 virus)
What HIV membrane protein protein binds to CXCR4, CCR5, and CD4 receptors on host cells?
gp120 envelope protein (the grabber)
What HIV membrane protein is responsible for fusion and entry of the virus?
gp41 envelope protein
What mutations are protective against HIV?
homozygous for mutation = immune
heterozyg = slower course of dz
If the ELISA is negative, what do you do next?
Tell the pt they don't have HIV.
Negative ELISA means no HIV- ELISA is a rule out test.
If the ELISA is positive, what do you do next?
ELISA has a high false-pos rate, so do a Western Blot to confirm.
Normal CD4 count vs AIDS dx
Normal = 500-1500
AIDS = <200
How can you make the dx of AIDS?
If an infant tests positive, how can you tell if they have HIV, or if their positive test is just bc of maternal Ab?
Check the infant's viral load.
Or, wait a few months and test again.
Prophylaxis for HIV+ at different CD4 levels
<50 continue TMP-SMX and azith; if pt has had prev hx of cryptococcal meningitis, then give fluconazole (but only w hx)
When should HAART be started?
Pt has AIDS-defining illness (PCP pneumonia)
Low CD4+ (<350)
High viral load
List protease inhibitors
NAVIR tease a protease.
How do protease and protease inhibitors work?
Normally, HIV virion assembly depends on HIV-1 protease, which cleaves the polypeptide products of HIV mRNA into their functional parts.
Protease inhibitors prevent HIV virions from being able to process their own DNA (prevents maturation of virions in progeny)
Nephrolithiasis is a side effect of which HIV drug?
Pancreatitis is a side effect of which HIV drugs?
Pancreatitis alone - Ritonavir (PI)
Pancreatitis + periph neuropathy - didanosine, zalcitabine, stavudine (NRTIs)
Lipodystrophy and hyperglycemia are side effects of which drugs?
Saquinavir, Indinavir, Amprenavir (PIs)
What are the side effects of PIs that are class effects (all drugs in the PI class cause them)?
GI intolerance (v common)
Cytochrome P450 inhibition (this one is not nec bad- can extend heart meds)
How do NRTIs work?
Nucleoside Reverse Transcriptase Inhibitors
They competitively inhibit nucleotide binding to Reverse Transcriptase, and therefore terminate the DNA chain
They need to be phosphorylated (activated) by thymidine kinase in order to work.
List the NRTIs
Zidovudine (ZDV, used to be AZT)
Have you dined (-vudine) with my nuclear family?
Which HIV drug causes Hepatic steatosis (fatty liver)?
Didanosine, Stavudine (NRTI)
Which HIV drug causes HPS rxns?
How do NNRTIs work?
Non-nucleoside Reverse Transcriptase inhibitors
Non-competitively (irreversibly) bind to inhibit RT.
Do NOT need to be phosphorylated to be active.
List the NNRTIs
Never Ever Deliver nucleosides.
Which class of HIV drugs causes rash?
Which HIV drug causes a false-pos test to cannabinoids?
Which NNRTI causes confusion as a side effect?
Which HIV drug causes bone marrow suppression?
ZDV zidovudine (NRTI)
Bone marrow suppression - neutropenia, anemia
GM-CSF can be used to reduce the suppression.
What HIV drug is a fusion inhibitor? How does it work?
Binds gp41, inhibiting the conformational chg req'd for its fusion w CD4 cells
Therefore, entry (and thus replication) is blocked
What drug is used during pregnancy to PMTCT?
(now, HAART as well)
What drug is given for HIV+ needle stick pts?
Zidovudine with Lamivudine
Which HIV drug is an integrase inhibitor? How does it work?
Integrase helps integrate viral DNA into host DNA- this blocks integrase.
What drug is a CCR5 antagonist? How does it work?
Binds CCR5 on macrophgs, inhibiting the gp120 confirmational chg (so gp120 can't grab on to it)
Pt must first have a test to see if their HIV is the R5 type.
Which HIV drugs cause lactic acidosis?
NRTIs (but not abacavir)
Which HIV drug causes megaloblastic anemia?
combo to control infection and avoid resistance
often 2 NRTIs + PI
Diarrhea caused by non-motile gram-neg org that does not ferment lactose
Gram-neg motile org that doesn't ferment lactose and causes diarrhea
Salmonella (salmon swim- motile!)
Diarrhea from gram-neg lactose+ with no fever
Food poisoning from undercooked hamburger
E. coli O157:H7
Food poisoning sympt after handling reptiles (turtles)
Pneumonia in immunocomp
Most common cause of atypical pneumonia
Pneumonia in alcoholic
Pneumonia from air conditioners
Most common pneumonia in kids <1yo
Most common cause of pneumonia in neonate (birth to 28 days)
GBS or Ecoli
Most common cause of pneumonia in kids and young adults (college students, military, prisoners)
Cause of pneumonia in pts w other health issues
Most common viral pneumonia
Woolsorter's dz (life threatening pneumonia)
Endogenous flora in 20% of adults that can cause pneumonia
Bacterial cause of COPD exacerbation
Pneumonia in ventilator pts
Pneumonia in CF pts
Rx for kids w meningits
Ceftriaxone (3rd gen)
+dexamethasone to reduce neurologic sequella
Rash seen in N. meningitidis
Purpura fulminans (big! and bad)
How to dx osteomyelitis
Radiographic bone scan or MRI
Male infant congenital defects which can lead to UTI
Posterior urethral valves (send urine back to bladder)
Elderly pt w delirium
UTI or anti-cholinergic drugs
CSF findings in bacterial meningitis
Same as fungal/TB meningitis, except for the cell type is different!
CSF findings in fungal/TB meningitis
Same as in bacterial meningitis except cell type is different (PMNs for bacterial)
CSF findings in viral meningitis
Normal or increased prs
Increased lymphocytes (will have lymphcytosis of the CSF)
Normal or increased protein
With viral, everything can be normal in the CSF except for the lymphocytosis.
Organisms with urease
Particular Kinds Have Urease
What does urease do?
What organism makes urease and causes stones?
Breaks down urea into ammonium.
Proteus mirabilis makes urease: Ammonium can bind to magnesium and phosphate and make stones (staghorn struvite stones)
If leukocyte esterase urine test is positive, what does this indicate?
That there is inflammation.
May be bacterial, but not necessarily so.
If a nitrate urine test is positive, what does this indicate?
That a gram-neg organism is present.
RX for UTIs
TMP-SMX, fluroquinolones, nitrofurantoin
If prego: 1st/2nd gen cephalosporins, aminopenicillin, nitrofurantoin
What is the cause of unilateral hearing loss in a neonate?
What measures are used to prevent vertical txmsn of HIV?
What is the cause of temporal lobe encephalitis in a neonate?
Herpes simplex virus
What does Parvo B19 cause in pregnancy?
Cause of bacterial vaginosis
Only an STD sometimes.
Clue cells have rough borders.
Risk factor for nosocomial Candida albicans?
Hyperalimentation (aka overeating/getting too many nutrients
often bc of total parenteral nutrition
Neonate has snuffles (blood-tinged nasal secretions)- what do they have?
Neonate w rash followed by desquamation of hands/feet
pH, findings, wet prep for:
physiologic vag discharge
physiologic: low pH (vag is acidic), usu px is young girl in puberty; wet prep- WBCs
Candida: low pH, cottage cheese, wet prep- budding yeast w pseudohyphae. Use KOH prep to see better.
Trich: high pH, irritation, itchy, strawberry cervix, see triangular organisms on wet prep
Bacterial vag: high pH, fishy smell, greenish. See clue cells on wet prep.