9/26 CNS Infections - Casey Flashcards Preview

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Flashcards in 9/26 CNS Infections - Casey Deck (29):
1

abscess

collection of pus that becomes walled off in tissues

2

encephalitis

inflammation of brian

3

encephalopathy

altered brain fx

4

meningitis

inflammation fo meninges

5

how can you get a brain abscess?

 

most common locations?

 

main pathogens?

  • contiguous spread
  • hematogenous seeding
  • post-traumatic
  • cryptogenic

 

  1. temporal/frontal
  2. frontal/parietal
  3. cerebellar
  4. occipital
  5. multiple locations → implies hematogenous seeding!

 

  • streptococci 60-70%
  • bacteroides 20-40%
  • enterobacteriaceae 23-33%
  • staph aureus 10-15%

6

clinical presentation of brian abscess

  • fever might be absent
  • indolent, slow progression more common than fulminate
  • headache is common
  • focal neuro findings/seizures
  • nausea/vomiting
  • nuchal rigidity is relatively uncommon

7

diagnostic test

MRI, CT, blood cultures, sterotactic biopsy for culture

  • LP contraindicated if abscess suspected → dont want to risk herniation!

8

treatment of brain abscess

medical or med&surgical drainage

  • choose antibiotics based on organisms theyll clear out AND ability to cross bbb

9

suppurative (pus-forming) foci

cranial subdural empyema

  • neuro emergencies
  • usually bacteriema
  • headache/seizures common
  • same bacteriology as in brain abscess

spinal subdural empyema

epidural abscess (most commonly seen)

  • almost always related to sinus disease
  • elliptical apprearance

 

10

paraspinal abscesses

 

gen features

  • may be epidural or subdural
  • usually due to bacteremia but can also be due to contiguous spread
  • surgical almost always required to prevent spinal cord compression

​*Staph aureus is most common infecting organism

11

spinal subdural abscess

presentation

radicular pain, urinary retention, constipation, leg weakness, hyperreflexia

 

dx:

  • MRI with gadolinium 
  • CT myelogram essential

tx:

  • steroids, antibiotics, surgical decompression

12

spinal epidural abscess

 

where (link to anatomy)

sx, dx

where?

  • posterior > anterior
    • true epidural space posterior and lateral to spinal cord below foramen magnum
    • potential epidural space anterior to spinal cord bc dural is adherent to vertebral bodies
  • thoracic > lumbar > cervical

    • larger epidural spaces contain more inf-prone fat

sx of cord compression

 

dx:

  • positive blood cultures
  • often simultaneous vertebral osteomyelitis (vert bodies degen)
  • CSF analysis:
    • small number of polys with markedly elevated protein and normal/low glucose
    • culture frequently negative

13

chronic meningitis

 

infectious causes

infectious: TB, cryptococcus, coccidioidomycosis, histoplasmosis, Lyme disease, syphillis

14

infectious chronic meningitis

 

TB

TB

  • PPD often negative → anergy (lymphocytes not working bc you're acutely infected)
  • AFB smears rarely positive
  • NEED HIGH INDEX OF SUSPICION
  • CSF shows high protein, low glucose, low lymphocytes

15

infectious chronic meningitis cryptococcus

  • CAN occur in normal host
  • USUALLY occurs in immunodeficient host
  • dx: India ink, cryptococcal antigens are useful
  • other fungal meningitis present similarly but cant test using India ink exam equivalent

16

infectious chronic meningitis

Lyme disease

can occure in any stage of Lyme disease

  • nonspecific lymphocityic meningitis
  • often accompanies Bell's palsy → uni or bilat

dx: simultaneous serum analysis & CSF analysis

17

infectious chronic meningitis

syphilitic

can occur as secondary syphilis 40% of time

meningitis most frequent manifestation of tertiary syphilis

asymptomatic approx 30% of time

 

common: headache + HIV (secondary), psych behavior ward pts (tertiary)

18

meningovascular syphilis

endarteritis obliterans → infarction of small vessels

  • stroke-like syndrome
  • seizures

19

parenchymatous neurosyphilis

destruction of nerve cells in cerebral cortex manifesting as general PARESIS or TABES DORSALIS

  • psych and neuro manifestations

 

PARESIS: personality, affect, reflexes, eye, sensorium, intellect, speech

tabes dorsalis

  • shooting pain
  • ataxia
  • sphincter disturbance
  • periph neuropathy (decr vibration sense)
  • cranial neuropathy

other manifestations: uveitis, deafness, optis neuritis or atrophy

20

neurocysticerocosis

most common presentation as seizures

  • may or may not have live parasites

 

dx:

  • CSF: lymphocytic pleocytosis, maybe low glucose
  • serology + hx + CT finding is most common way to make a dx

 

21

noninfectious chronic meningitis

 

 

  • neoplasms/paraneoplastic syndromes
  • sarcoidosis
  • vasculitis
  • drug-induced

22

meningitis vs. encephalitis

altered mental status diffs are key

  • early meningitis → no AMS
  • encephalitis → AMS early

region of inflammation: meninges vs. brain

CSF exam: similar in both

stiff neck more common in meningitis (but most adults with meningitis dont have one either)

 

23

viral encephalitis

 

CSF exam

cell count <500 in 90% of cases

  • lymphocytic predominance
    • more polys in EES and some enteroviruses
  • RBC > 500 in HSV, CTFV, CEV
  • low glucose??? consider alt diagnosis

24

HSV vs non-HSV encephalitis

clinical features do not reliably distinguish

infero-medial and frontal-parietal localization? acyclovir initiation

 

EEE hits basal ganglia and thalami

  • highest mortality

St Louis enceph

WEE

California enceph

West Nile enceph

less common: varicella zoster, EBV, HIV, HHV6

25

Eastern Equine encephalitis

avian reservoir - daytime feeding mosquito vector

Atlantic and Gulf states

all ages, especially children

 

  • high incidence of neuro sequellae
  • up to 75% mortality

26

West Nile virus

avian reservoir - Culex pipiens mosquito vector

  • incubation period 5-5 days
  • usually self limited
  • fatality rate up to 3-15% in elderly

27

non-viral encephalitis

bacterial pathogens: Listeria, Salmonella, Nocardia

lots of others: Spirochetes, Rickettsia, parasites, Mycoplasma, drugs, vasculitis, carcinomatosis

 

PML : progressive multi-focal encephalopathy (JC virus)

28

Naegleria fowleri

fresh, non-Cl warm water

cause acute hemorrhagic encephalitis

CSF: high PMN count, low glucose, bloodies within days

tx: amphotericin, rifampicin, fluconazole, miltefosine, azithromycin

 

99% mortality

29

postinfectious encephalitis

Acute Disseminated Encephalomyelitis (ADEM)

  • demyelination in white matter
  • no direct infection

usually follows viral illness by 5-21 days

nonspecific neuro symptoms

CSF shows inflammation

tx: glucocorticoids

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