Week 1 - CNS Pathogens

Question 1

Types of infection

Answer 1

leptomeningeal= meningitis
parenchymal= encephalitis
spinal cord= myelitis (meningoencephalitis when both)
sub/epidural= empyema

Question 2

Neurotropism

Answer 2

viral specific receptors on nerves= polio and mumps
capsule adheres to meninges= B-strep, E coli
viral spread along nerves= HSV, rabies, zoster

Question 3

Meningitis

Answer 3

headache, photophobia, stiff neck (nuchal rigidity)
Hyperacute= meningococcal meningitis
acute= bacterial
subacute/chronic= TB, syphilis
aseptic= viral, less severe, during summer

Question 4

Bacterial meningitis

Answer 4

usually acute and pretty severe, needs rapid tx
layer of exudate under meninges, contains PMNs
complications= infarcts, secondary vasculitis, phlebitis and infarction of outer veins
Newborns= B-strep
Older kids= Strep pneumo, N meningitidis, also H flu if unvacc
Adults= N meningitidis, strep pneumo,, also Listeria in very old

Question 5

Brain abscesses

Answer 5

parenchymal infxn, circumscribed fibrous capsule
sx: focal deficits
usually bacterial or fungal,, strep or staph in immunocompetent

Question 6

Encephalitis

Answer 6

inflammation of the brain parenchyma
Bacterial: TB, syphilis, Lyme
can be viral or fungal too

Question 7

TB in the CNS

Answer 7

Most common= meningoencephalitis
CSF: elevated pressure and protein, decreased glucose, lots of lymphocytes
PCR for TB
sx: headache, lethargy
granulomas with lymphocytes and macrophages,, primarily in base of brain
can cause secondary hydrocephalus
Tuberculoma (caseous necrosis lesion
Osteomyelitis- spondylitis (Pott’s Disease)- granulomas in the vertebre

Question 8

Neurosyphilis

Answer 8

tertiary stage of treponema pallidum
General paresis: thickened meninges and atrophic brain
Meningovascular: severe at base of brain, meningitis and multifocal arteritis, infarcts and hydrocephalus, focal deficits
Tabes dorsalis:degeneration of posterior column of spinal cord, lightening pains and shuffling broad gait

Question 9

Viral meningoencephalitis

Answer 9

perivascular lymphocytes, microglial nodules, neuronophagia
Arbovirus: epidemic encephalitis, generalized neuro deficits, west nile
Herpes: HSV1 most common sporadic acute encephalitis,, mood, memory, behavior abns,, focal abns in frontal and temporal lobes [HSV2=neonates, CMV=AIDS pts]
HIV: infects microglia,, AIDS dementia complex, microglial nodule containing multinucleated cells
Progressive multifocal leukoencephalopathy (PML): immunosuppressed pts, JC virus, infects oligodendrocytes, white matter

Question 10

Fungal meningoencephalitis

Answer 10

immunocompromised hosts
Aspergillus: multiple foci of hemorrhagic necrosis
Cryptococcis: encephalitis or cryptococcoma abscess, intraparenchymal cysts

Question 11

Parasites in CNS

Answer 11

amoeba, plasmodium (malaria), toxoplasma, trypanosoma (sleeping sickness), cystercus
Toxoplasmosis: multiple localized necrotic lesions, pseudocysts or free

Question 12

Epidural or subdural empyemas

Answer 12

usually bacterial: staph or strep

can be from trauma, ear infxn, mouth infxn, surgery, etc

Question 13

Adult acute (bad) meningitis

Answer 13

Strep pneumoniae

Question 14

older/alcoholic acute meningitis

Answer 14

Listeria

Question 15

AIDS pt with subacute meningitis

Answer 15

cryptococcus

Question 16

neurosurgery pt with acute meningitis

Answer 16

staph, maybe E coli

Question 17

college frechman with acute meningitis

Answer 17

Neisseria meningitidis

Question 18

adult with subacute mild meningitis in the summer

Answer 18

enteroviral

Question 19

immigrant with subacute meningitis

Answer 19

TB

Question 20

LP CSF results interpretation

Answer 20

Viral: monocytes, normal glucose, low-med protein
Bacterial: neutrophils, low glucose, med-high protein
TB: monocytes, low glucose, low-med protein
crypto: monocytes, low glucose, low-med protein

Question 21

Treatments for meningitis

Answer 21

strep pneumo: IV ceftriaxone, vanco, steroids
Listeria: add ampicillin
fungal: amphotericin B

Question 22

adult with encephalitis (global def)

Answer 22

worry about HSV (acyclovir)

Question 23

adult with encephalitis in the summer (global def)

Answer 23

arboviral, Lyme disease

Question 24

AIDS pt with encephalitis (focal def)

Answer 24

toxoplasma, PML

Question 25

adult with subacute (months) encephalitis

Answer 25

prions

Question 26

H flu meningitis

Answer 26

G-, polysaccharide capsule, has a vaccine type B= ribose and ribitol capsule most invasive disease occurs 3mo-3yrs

Question 27

N meningitidis meningitis

Answer 27

has lipooligosaccharide (LPS), polysaccharide capsule, and fimbriae there is a meningoccal vaccine (quadrivalent) collonizes nasal pharynx

Question 28

Strep meningitis

Answer 28

strep pneumo: diplococci, teichoic acid, oropharynx there is a pneumoccal vaccine Group B: B-hemolytic, inhabits pharynx, vagina. Neonates, tx=penicillin

Question 29

Rabies

Answer 29

rhabdovirus, ssRNA, enveloped, one serotype, can be tx through organ transplant too Incubation period: asymptomatic 3-6wk Prodrome: vague sx, nervousness, anxiety Acute: two forms, fulminant(furious) or paralytic(dumb) There is a vaccine, and post-exposure prophylaxis (PEP) PEP: passive+active immunization, 4 doses almost always fatal once sx appear, but induced coma bc rabies is metabolic ds may work

Question 30

Creutzfeldt-Jakob Disease

Answer 30

Prion- virus-like agent, infectious protein progressive dementia leading to ataxia, paralysis and death in 6mo mostly sporadic, but rare genetic component spongiform encephalopathy long incubation period, relatively quick disease progression no treatment