micro

Question 1

what type of genome does poliovirus have?

Answer 1

+ssRNA

Question 2

what type of genome do polyoma viruses have?

Answer 2

circular dsDNA

Question 3

what are the two human polyoma viruses and what do they cause?

Answer 3

BK: little disease, seen in urine of AIDS patients
JC: PML

Question 4

where do replication and assembly occur for polyoma viruses?

Answer 4

both in nucleus

Question 5

what are the T antigens?

Answer 5

early genes in polyoma virus replication: initiate DNA replication and responsible for transformation
small and large: immortalize cells
small and medium: transform cells

Question 6

what is progressive multifocal leukoencephalopathy? what is the pathogenesis?

Answer 6

progressive demyelinating disease of CNS caused by JC virus

infects and lyses oligodendrocytes

Question 7

what are the three main symptoms of PML?

Answer 7

clumsiness, progressive weakness, speech problems

Question 8

how is PML treated in AIDS and transplant patients?

Answer 8

AIDS: optimize HAART therapy->50% mortality
transplant: alter (don’t halt) immunosuppressive therapy->still 80% mortality

Question 9

what is Kuru? what is its presentation? how is it transmitted?

Answer 9

prion disease in Papua New Guinea transmitted by ritualistic cannibalism: “tremble with fear”

Question 10

what is the primary and secondary presentation of Creutzfeldt-Jakob disease? how does it end?

Answer 10

1. dementia and myoclonus
2. ataxia/cerebellar dysfunction
   - akinetic mutism

Question 11

what prion disease has been shown to be transmitted by dural grafts, corneal grafts, pituitary-derived hGH? which have short incubation?

Answer 11

Creutzfeldt-Jakob disease

dural and corneal grafts

Question 12

how is variant Creutzfeldt-Jakob disease transmitted?

Answer 12

beef products and blood

Question 13

which is more contagious and why: vCJD or CJD?

Answer 13

vCKD: also infects tonsils, spleen, lymph nodes, appendix

->diagnose by tonsil biopsy

Question 14

what are the primary manifestations of vCJD? what is the end stage presentation?

Answer 14

• anxiety and depression
• sensory abnormalities, esp. visual late
• akinetic mutism

Question 15

what is required to get vCJD?

Answer 15

vCJD: methionine at codon 129

Question 16

how is GSS disease contracted

Answer 16

familial, AD

Question 17

what prion diseases show amyloid plaques?

Answer 17

GSS

Question 18

what is the primary presentation of GSS?

Answer 18

gait abnormalities and ataxia

-no dementia

Question 19

which prion disease actually rarely shows spongiform changes?

Answer 19

fatal familial insomnia

Question 20

what is the presentation of FFI?

Answer 20

sleep disturbances and autonomic dysfunction

Question 21

name the prion disease according to presentation: insomnia and autonomic dysfunction; dementia and myoclonus; ataxia and gait abnormalities; anxiety/depression/sensory abnormalities

Answer 21

FFI, CJD, GSS, vCJD

Question 22

what bacteria cause meningitis in infants?

Answer 22

GBS, G- enteric bacilli, Listeria

Question 23

what bacteria cause meningitis in children 3mo-2yr?

Answer 23

S. pneumo, Neisseia, H. flu type B

Question 24

what bacteria cause meningitis in children >2?

Answer 24

Neisseria and S. pneumo

Question 25

what bacteria cause meningitis in immunocompromised?

Answer 25

Staph spp., G- enteric bacilli, Pseudomonas

Question 26

how should meningitis be empirically treated? what do they cover?

Answer 26

1. dexamethasone 2. 3rd gen ceph for strep, Neisseria, H. flu 3. vanc for resistant strep and G-'s 4. penicillin for Neisseria 5. ampicillin for listeria 6. doxycycline to cover RMSF and Lyme 7. acyclovir to cover herpes encephalitis

Question 27

what type of meningitis is splenic dysfunction a risk factor for?

Answer 27

Strep. pneumo

Question 28

what is choline binding protein?

Answer 28

virulence factor for S. pneumo, important for crossing BBB in meningitis

Question 29

how is meningococcal meningitis diagnosed? how is it cultured

Answer 29

rapid latex agglutination test on CSF | on chocolate agar

Question 30

how does Neisseria escape the immune system?

Answer 30

phase variation: turn off capsule on invasion of mucosal cells, turn back on in bloodstream

Question 31

what causes the fever and rash of meningococcemia?

Answer 31

endotoxin: LPS

Question 32

how can individuals exposed to Neisseria be prophylactically treated?

Answer 32

1 pill of ciprofloxacin | rifampin

Question 33

how is H. flu cultured?

Answer 33

chocolate agar

Question 34

why does type B H. flu cause meningitis?

Answer 34

has antiphagocytic polyribotol capsule

Question 35

what is used to treat H. flu meningitis? what is it commonly resistant to?

Answer 35

3rd gen cephalosporin | ampicillin resistant

Question 36

why is a gram stain of CSF not very useful in ruling out bacterial meningitis?

Answer 36

Listeria doesn't gram stain well, intracellular

Question 37

diarrhea/abdominal discomfort may precede meningitis caused by what bacteria?

Answer 37

listeria

Question 38

what is the treatment of listeria?

Answer 38

ampicillin

Question 39

which cryptococcus species causes meningitis primarily in HIV and which accounts for most of fungal meningitis in healthy individuals?

Answer 39

HIV: neoformans healthy: gatii

Question 40

what type of fungus is cryptococcus?

Answer 40

encapsulated yeast

Question 41

what is the disease progression of fungal infection to meningitis?

Answer 41

initially asymptomatic pulmonary infection | chronic infection leads to meningitis

Question 42

how can cryptococcus be diagnosed in lab?

Answer 42

yeast with halos on India ink

Question 43

how is cryptococcus meningitis treated?

Answer 43

amphotericin B and flucytosine

Question 44

how is meningitis due to Exserohilum rostratum treated?

Answer 44

IV voriconazole for 3 months

Question 45

what characteristically causes necrosis of temporal lobe? what CSF finding indicates necrosis? how can it be visualized? how is it treated?

Answer 45

HSV-1 encephalitis, RBC's in CSF, not usually seen on CT, acyclovir

Question 46

which flaviviridae cause encephalitis? what is the genoma?

Answer 46

+ssRNA | West Nile, St. Louis, and Japanese encephalitis

Question 47

what is the most common cause of arboviral pediatric encephalitis in US? how does it present? what type of virus is it?

Answer 47

La Crosse virus seizures and focal neurological signs bunyavirus

Question 48

what is the genome of bunyaviridae? how is it different from influenza?

Answer 48

segmented -ssRNA | replication in cytoplasm, mRNA's not spliced

Question 49

what is the genome of rabies virus?

Answer 49

enveloped, non-segmented -ssRNA | bullet-shaped

Question 50

exaggerated gag reflex is a sign of what disease?

Answer 50

rabies

Question 51

what virus uses ambisense replication?

Answer 51

Lymphocytic Choriomeningitis Virus (LCMV)->arenavirus

Question 52

how is LCMV spread?

Answer 52

aerosolized from rodent excreta/saliva

Question 53

how does a brain abscess show up on CT? how is it treated?

Answer 53

ring-enhancing lesion with surrounding edema | 3rd gen cephalosporin and metronidazole to cover Bacteroides fragilis

Question 54

what is the primary cause of spinal epidural abscess? what is the major sign and key feature?

Answer 54

S. aureus (90%) point tenderness, esp. to touch key feature: worse pain on lying down

Question 55

how does RMSF cause encephalitis?

Answer 55

attacks vascular endothelium: systemic vasculitis attacks brain parenchyma causing confusion, seizures, focal deficits

Question 56

how is RMSF treated? Lyme disease?

Answer 56

doxycycline for both, ceftriaxone for Lyme disease

Question 57

what are two presentations of neurosyphilis? how is it treated?

Answer 57

general paresis, tabes dorsalis (dorsal column demyelination) high dose IV penicillin

Question 58

how does TB affect the brain? where is most severe? what is a common complication?

Answer 58

chronic granulomatous meningitis, esp. severe at base of brain; thickened basal meninges cause entrapment of CN's