CNS infections Flashcards

1
Q

What are the common causes of bacterial meningitis in each of the following age groups

  • newborn
  • 1-23mo
  • 2-18yrs
  • 19-50yrs
  • 50+

Common cause of Nosocomial Bacterial meningitis?

A

newborn: Group B strep

1-23mo: Strep Pneumo

2-18: Niesseria meningitidis

19-50: Strep Pneumo

50+: Strep pneumo

Nosocomial: E coli, Klebsiella pneum, Pseudomonas aeruginosa

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2
Q

Meningitis is shifting from a peds to adult dz, T/F?

A

True, most commonly Strep pneumo.

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3
Q

Risk factors for development of meningitis?

A
  • asplenia
  • corticosteroid use
  • immune compromised/HIV
  • exposure to someone with meningitis
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4
Q

Meningitis/Encephalitis pathogenesis

A

-bacteria cause vasogenic brain edema, increased intracranial pressure resulting in brain ischemia, cytotoxic injury and neuronal apoptosis.

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5
Q

Meningitis

  • presentation
  • PE special tests
  • Work uP
A

Presentation”

  • Fever*
  • Nuchal rigidity*
  • change in mental status(lethargy)*
  • HA
  • Photophobia
  • characteristic rash (neisseria); nonblanching
  • N/V
  • seizures
  • papilledema

PE Test:

  • kernig Sign: inability to alllow full extension of the knee when hip is flexed at 90 degrees
  • brudzinski sign: spontaneous flexion of hips during attempted passive flexion of the neck

Work Up:

  • Labs: CBC w/ diff, CMP, UA, blood cultures
  • gram stain
  • LP: this is diagnostic**
  • possible CT to R/O mass lesion or other cause of IICP. Not always required.
  • -if LP is deferred or delayed get blood cultures and start emperic abx
  • remember always get CT before LP if..
  • immunocompromised
  • Hx of seizure within 1 week
  • papilledema
  • altered level of conciousness
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6
Q

What are the common bugs for each of the following:

  • gram + diplococci
  • gram - diplococci
  • gram - coccobacilli
  • gram + rods and coccobacilli
A

Gram + diplococci = strep pneumo

gram - diplococci = niesseria meningitidis

gram - coccobacilli = h flu

gram + rods and coccobacilli = listeria

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7
Q

Meningitis:

empiric tx

A

Strep pnemo and meningococcal:
-Cefotaxime or ceftriaxone + vancomycin

Listeria:
-ampicillin + gentamycin or bactrim

Nosocomial:
-ceftazidime + vancomycin

Tx is generally7-21 days
*usually doubled if immunocompromised

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8
Q

Neurological complications of bacterial menintigis

A
  • neurological:
  • -cerebral edema
  • -seizures
  • -cranial nerve palsies
  • -hemiparesis

Cerebrovascular:

sensorineural hearing loss (strep pneumo)

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9
Q

What is the role of dexamethasone in tx of meningitis?

A

-adding dexamethasone before of with the start of abx has been evaluated as adjuvent therapy in attempt to diminish rate of hearing loss, cerebral edema, and neurologic complications..

reduces mortality and neurologic disability in pts w/ GCS 8-11 and strep pneumo*

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10
Q

Prevention of Meningitis

A
  • dont share saliva
  • good hand washing
  • Vaccine:
  • -HIB
  • -PCV13 (child)
  • -PPSV23 (adults greater than 65, young adults)
  • -Menactra (11-18 for those who havent yet been vaccinated)
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11
Q

Aspetic meningitis

  • what is this?
  • presentation
  • Dx
A

what: clinical and lab evidence for meningeal inflammation w/ negative bacterial cultures, MC enterovirus
“non-bacterial”

Presentation:
-Fever, HA, stiff neck, photophobia, rash

Dx:

  • hx
  • LP

Tx:

  • resolves w/o therapy
  • if uncertain treat with empiric abx
  • supportive
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12
Q

Encephalitis

  • causes
  • clinical presentation
  • dx
  • complications
A

Cause:

  • viral** (herpes simplex 1), post infectious, autoimmune, paraneoplastic, medication induced
  • West Nile
  • Lymes
  • Rocky Mtn Spotted Fever
  • TB

Clinical presentation:

  • altered mental status***
  • seizures*
  • exaggerated DTR
  • hemiparesis

Dx:

  • LP
  • CT r/o space occupying lesion
  • MRI*** detects demyelination
  • EEG abnormal

Complication:

  • status epilepticus
  • SIADH
  • cardiorespiratory failure
  • DIC
  • death
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13
Q

What are the big differences between meningitis and encephalitis?

A

meningitis = photophobia, nuchal rigidity, lethargy not change in mental status

Encephalitis: altered mental status (confusion), NO meningeal irritation (photophobia, nuchal rigidity)

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14
Q

Viral Encephalitis:

  • CSF characteristics
  • dx
A

CSF: increased WBC with differential showing mostly lymphocytes, elevated protein, normal glucose

dx:
- knowledge of pt immune status
- brain bx as last resort

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15
Q

West Nile Cause of Encephalitis:

  • sx & neurologic signs
  • tx
A

Sx:
-fever, stiff neck, sore throat, N/V, stupor..convulsions..coma

neurologic signs:
-UMNL = exaggerated DTR, spastic paralysis, primitive reflexes

Tx:
-Ribavirin

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16
Q

Rocky Mtn Spotted Fever:

  • cause
  • sx
  • Dx
  • tx
A

Cause: rickettsia rickettsii

Sx:
-fever, HA, nausea, rash (blanching) on palms & soles 1st,

Dx:

  • clinical suspicion
  • rash absent in 20%
  • hyponatremia, low platelets, elevated LFT = RMSF

Tx:
-doxycycline x 7 days

17
Q

Lymes Dz Encephalitis

  • cause
  • sx
  • Tx
A

Cause: borrelia burgdorferi tick

Sx:

  • erythema migrans rash
  • arthritis
  • neuro/cardiac findings
  • encephalopathy or polyneuropathy

Tx:
-doxycycline

18
Q

Brain Abscess

  • basic pathophysiology
  • clincial features
  • dx
A

Patho:

  • hematogenous
  • ears/sinus/mouth
  • trauma
  • post neurosurgical

Features:
Classic triad:
-HA, fever, focal deficit *

others:
- seizure, confusion, vomiting, visual field deficit, nystagmus

Dx;

  • CT w/ contrast or MRI
  • LP CONTRAINDICATED!!!!!!!!!
  • needle guided bx or aspiration for confirmation or to direct tx