CNS Infections Flashcards by Karina Katchko

What is another name for a leptomeningeal inflammation?

meningitis

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What are the types of penchymal inflammation?

encephalitis, cerebritis, myelitis

brain abscess

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What is another name for subdural or epidural inflammation?

subdural/epidural empyemas

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How does infection get into the brain?

arterial spread
retrograde venous spread
local extension (air sinuses, infected tooth)
neural route (PNS--->CNS)
direct implantation (trauma, iatrogenic)

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What does the word neurotropism mean?

having a special affinity for nervous tissue

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What is the most common cause of meningitis?

strep pneumo

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What are the clinical signs/symptoms of meningitis?

headache, photophobia, stiff neck (nuchal rigidity), clouded consciousness, fever

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What are the 4 clinical types of meningitis?

hyperacute 1 wk

aseptic

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What are the key features of hyperacute meningitis?

meningococcal meningitis (n. gonorrhea)
sparse inflammation, numerous organisms, congestion

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Waht are the key features of acute meningitis?

usually bacterial
from hematogenous spread
exudate present, numerous PMNs in subarachnoid space

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What are the key features of subacute/chronic meningitis?

TB, syphillis
brain parenchyma commonly affected as well
lymphocytes, plasma cells, macrophages in exudate

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What are the key features of aseptic meningitis?

usually viral
much less fulinant than bacerial meningitis and less severe sx
summer and early fall
lymphocytic infiltrate in meninges

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What are come complications of bacterial meningitis?

brain infarcts
phlebitis (which may cause infarction of underlying brain tissue)
secondary vasculitis

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What organisms commonly cause aseptic meningitis?

arboviruses

enterovirus (most common) [echovirus, coxsackie]

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What are the clinical signs/sx of brain abscesses?

focal deficits, raised IC pressure

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What are brain abscesses usually caused by in immunecompetent hosts?

strep

staph

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How do brain abscesses like to spread?

toward the ventricles

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What are some common abscess cuasing pathogens in immunocomprimised hosts?

toxoplasma
nocardia
listeria
gram neg bacilli
mycobacteria
fungi

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What is encephalitis?

inflammation of brain parenchyma
if in spinal cord-myelitis
if meninges and brain-meningoencephalitis

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What are common causes of bacerial meningoencephalitis?

TB
syphilis
Lyme disease

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What do you find in the CSF with TB meningoencephalitis?

elevated pressure and protein
decreased glucose
lymphocytic pleocytosis
cultures for AFB positive in 50%

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What are signs and symptoms of TB in the CNS?

headache
lethargy
confusion
vomiting

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What does TB in the CNS look like on gross examination?

mass lesion with central necrotic core or caseation, surrounded by fibroblasts, epitheliod histocytes, giant cells and lymphocytes

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What is another name for TB osteomyelitis?

spondylitis/pott’s disease

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What is TB osteomyelitis?

granulomatous process involving vertebral bodies and discs causes epidural abscesses can lead to cord compression & vertebral collapse

Describe neurosyphilis?

tertiary states | months-yrs after initial infection

What are the major forms of neurosyphilis?

``` general paresis (paretic neurosyphilis) meningovascular tabes dorsalis ```

What are the key features of general paresis?

gradual impairment of cognition/attention thickened meninges and atrophic brain meningeal & parenchymal perivascular lymphocytes, plasma cells, microglia

What are the key features of meningovascular type neuropyphilis?

chronic meningitis and multifocal arteritis severe at base of brain causes infarcts and hydrocephalus meningeal & arrterial/arteriolar lymphocytes and plasma cells with collagenous thickening of wall and eventual occlusion focal neuro deficits due to vascular compromise 2ary to arteritis

What are the key features of tabes dorsalis?

chronic inflammation in dorsal roots and ganglia w/loss of neurons and assoc. deg of posterior columns "lightening pains" or paraesthesias in affected roots, loss of position/vibratory sense, shuffling broad based gait

What are key general features of viral (meningo)encephalitis?

perivascular lymphocytes microglial nodules neurnophagia

What specific organisms commonly cause viral meningoencephalitis?

arobvirus herpes virus HIV progressive multifocal leukoencephalopathy

Which virus is the most common cause of psoradic acute viral encephalitis in temperate climates?

HSV1

What are signs of HSV infection in the CNS?

headache, fever, modd, memory, behavior abnormalities, drowsiness, coma

What is seen in HSV1 CNS infection on MRI?

focal abnormalities in frontal or temporal lobes

What is seen in the CSF with a HSV1 CNS infection?

increased pressure lymphocytic pleocytosis elevated prtein PCR for HSV1 DNA

What are gross findings of acute HSV encephalitis?

congestion, swelling, hemorrhagic necrosis of temporal lobs, insula, cingulate gyri, orbital cortex

What is the most common opportunist viral infection in AIDS patients? What does it cause?

CMV | subacute encephalitis

What demographic most commonly gets HSV2 meningitis?

neonates passing through birth canal in mother with active HSV2 infection

What are the signs/symptoms of arboviral meningoencephalitis?

seizures, confusion, stupor, delirium, coma & focal signs

What types of arboviral meningoencephalitis are common in the US?

``` west nile easter, western equine venezuelan st louis california ```

How does HIV infection enter the CNS?

by infecting microglia

What are the types of HIV involvement in the CNS?

HIV meningitis HIV encephalitis/leukoencephalopathy vacuolar myelopathy

When does HIV meningitis occur?

during acute flu-like illness at time of seroconversion

What are the clinical signs and symptoms of HIV encephalitis/leukoencephalopathy?

AIDS demential complex-cognitive and behavioral deterioration, eventually dementia, ataxia and tremor

What classic lesion is seen in HIV encephalitis/leukoencephalopathy?

microglial nodules containing multinucleated (giant) microglial cells (contain HIV virus)

What are hte key features of progressive multifocal leukoencephalopathy?

immunosuppressed hosts caused by JC virus, which infects oligodendrocytes JC virus infection during adolescence, reactivated w/immunosuppression

What are the histologic findings associated with PML?

enlarged oligodendrocyte nuclei immunostained for JC virus, at ege of area of early myeloin loss oligodendrocyte inlcusion irregular porrly defined areas of demyelination

What gross examination findings are associated wiht PML?

small foci of gray discoloration in white matter

What is seen on gross examination of cerebral toxoplasmosis?

mutliple localized necrotic lesions

What histologic findings are seen with cerebral toxoplasmosis?

tissue necrosis toxo organisms lying free in tissue organisms within pseudo cytes

Who gets cerebral toxoplasmosis?

fetus if infection occurs during pregnancy | immunocompromised hosts, esp AIDS pts

What are common fungal pathogens that can cause meningoencephalitis in immunocompromised hosts?

candida, mucor, aspergillus, cryptococcus, histoplasma, coccidiodes, blastomyces

Which fungi will most commonly cause secondary vasculitis?

aspergillus and murcor

What does aspergillus brain infection look like?

multiple foci of hemorrhagic necrosis with brain necrosis with inflammation may see vessel wall infiltration by fungal hyphae

Where does cryptococcus spread to the brain from?

the lungs

What are the main forms of cryptococcus in the CNS?

meningitis with or without brain parenchymal cysts (encephalitis) abscesses (cryptococcomas)

What CSF findings are present with fungal infection?

lymphocytes, hihg protein, normal or reduced glucose

What does cryptococcus infection look like on gross exam?

thickened meninges, esp over the sulci | multiple intraparenchymal cysts "soap bubbles"

What histologic findings are seen in cryptococcal meningitis?

organisms are single round year forms surrounded by capsule | minimal inflammatory reaction

What parasites besides toxoplasma can cause CNS infection?

amoeba plasmodium (malaria) trypanosoma cystercercus (taenia solium)

What causes most epidural and subdural empyemas?

staph and strep | via: frontal or mastoid sinusitis, otitis media, trauma, osteomyelitis or surgery

In what case can a CSF profile be misleading?

if tx already started

Which organism that causes meningitis also casues skin pettechiae?

neisseriea menigitidis

What populations does listeria monocytogenes cause menigitis in?

neonates, elderly, immunocomp. | also in alcoholics

When is e. coli meningitis seen?

in neonates, nosocomial

If a patient has AIDS and meningitis sx for a few weeks what organisms do you suspect?

1) crypto | 2) TB

If someone presents with a less severe form of meningitis in the summer what organisms do you think may be causing?

enterovirus/aseptic

If you suspect meningitis what do you do?

If CSF has increased WBC count and left shift what do you suspect?

bacterial infection

If CSF has high mononuclear count what do you suspect?

fungus or TB

What do increased lymphocytes in the CSF usually indicate?

fungus

If glucose in the CSF is normal what do you suspect?

viral cause

Which type of Abx MUST you use for meningitis?

CIDAL!!

What is the tx of choice for s. pneumo meningitis?

IV ceftriaxone

What is a good initial therapy for bacterial meningitis?

IV ceftriaxone, vancomycin, corticosteroids

What abx is added if listeria suspected?

ampicillin

What immunizations are available to try to prevent bacterial meningitis?

for pneumococcus, meningococcus and h influenza

If you suspect viral meningitis but patient presents in summer what do you have to think of?

arboviruses

What bacterial meningitis more commonly presents in summer?

lyme disease

What pathogens are at the top of your ddx in a patient with focal neurologic deficits?

JC | toxoplasma

If a patient has menigitis symptoms have been slowly worsening over a few months what type of disease do you have to include on the ddx?

prion disease

Does syphilis present with acute or chronic meningitis?

can present with either

CNS Infections Flashcards

(83 cards)