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Clin Med B 2 > (Enochs + some)Lecture 4: CNS Infections > Flashcards

(Enochs + some)Lecture 4: CNS Infections Flashcards

1
Q

What are the types of CNS infections?

A
  • Meningitis - inflammatory of meningies
  • Encephalitis - inflamm of brain itself
  • Meningoencephalitis - inflamm of both
  • Brain Abscess - collection of purulent material within brian tissue
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2
Q

What are the meningeal signs?

A
  • Nuchal rigidity
  • Brudzinski’s (neck)
  • Kernig’s (knee)
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3
Q

What physical manifestation is seen in increased ICP in infants?

A

Bulging fontanelle

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4
Q

What are the S/S of increased ICP?

A
  • Papilledema
  • Poorly reactive pupils
  • Abducens palsy (horizontal diplopia)
  • N/V
  • Bulging fontanelle in infants
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5
Q

describe each of the following:
- dura mater
- arachnoid mater
- subarachnoid space
- pia mater

A
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6
Q

What layers of the meninges does meningitis typically affect?

A
  • Arachnoid mater
  • Pia mater
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7
Q

What are the typical colonization areas for pathogens that cause meningitis?

A
  • Nasopharynx
  • Respiratory tract
  • Skin
  • GI/GU tracts
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8
Q

What are the two ways pathogens spread to the CNS?

A
  • Hematogenous (MC)
  • Direct contiguous spread via face sinuses (sinusitis, OM, trauma, neurosurgical)
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9
Q

How can newbornes get bacterial meningitis

A
  • pathogens colonized from the maternal intestinal or genital tract
  • transmitted from nursery personnel or caregivers at home
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10
Q

What is the #1 community acquired bacteria to cause meningitis?

What are the other 4 bacterial causes?

A

Strep pneumo (MC in adults > 20)

Group B strep
N. meningitiditis (causes SEVERE meningitis)
H flu type B
Listeria monocytogenes

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11
Q

What are the most common healthcare acquired bacterial meningitis pathogens and when does it occur?

A
  • Staph aureus and coagulase-negative staph (normal skin flora)
  • MC after neurosurgical procedures
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12
Q

What is the MC bacteria that causes meningitis in neonates?

A
  1. GBS
  2. E. coli
  3. gram neg bacilli
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13
Q

What is the MC bacteria that causes meningitis in children > 1 month?

A
  1. Strep pneumo
  2. N. meningitiditis
  3. H flu (unvaccinated)
  4. GBS
  5. Gram neg bacilli
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14
Q

What is the classic triad of bacterial meningitis?

A
  1. Headache (MC)
  2. Fever (2nd MC)
  3. Nuchal rigidity/meningeal signs
  4. ALOC/AMS (sometimes)

First 3 occur 50% of all cases

2 out of 4 are present in almost all cases

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15
Q

What additional S/S are seen in bacterial meningitis for adults?

A
  • N/V
  • Photophobia
  • Increased ICP (papilledema, CN palsy)
  • Meningococcal rash (petechiae or purpura)

Presence of meningococal rash suggests N. meningitiditis, which is more severe.

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16
Q

what symptom is associated with septic N meningitidis

A

maculopapular rash that become petechial and/or purpuric involving the trunk, LE, mucosal membranes, conjunctiva

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17
Q

How might an pediatrics present in bacterial meningitis?

A
  • Restlessness
  • V/D
  • Poor feeding
  • Respiratory distress
  • Seizures
  • Jaundice
  • Bulging fontanelle (infants)
  • fever/hypothermia

Kernig and brud is NOT reliable in younger children

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18
Q

What are the historical red flags for bacterial meningitis?

A
  • Recent exposure
  • Recent illness/abx tx (sinusitis, otitis, pna, ect)
  • Recent travel to endemic areas (sub-saharan africa)
  • Penetrating head trauma
  • CSF otorrhea or CSF rhinorrhea (hx skull fx)
  • Cochlear implants
  • Recent neurosurgery (esp. VP shunts)
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19
Q

What is the absolute #1 treatment for bacterial meningitis?

A

Starting Empiric ABX

Goal is 60 minutes to starting abx!

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20
Q

What two things are of upmost importance in diagnosing bacterial meningitis?

A
  • Blood cultures x2
  • LP
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21
Q

What would prompt us to order a CT scan prior to performing an LP?

A
  • Immunocompromised state
  • Increased ICP S/S
  • History of CNS disease
  • New onset seizures
  • Papilledema
  • ALOC
  • Focal neurologic deficit

DO NOT DELAY EMPIRIC ABX THERAPY FOR LP OR CT

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22
Q

What are the landmarks and location for LPs?

A
  1. Iliac crest/PSIS
  2. L2-L3, L3-L4 or L4-L5 intervertebral spaces
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23
Q

What does high flow of CSF from a LP suggest?

A

Increased ICP

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24
Q

What are the 4 tubes for CSF analysis?

A
  1. Cell count and diff
  2. Glucose and protein
  3. Gram stain, C&S
  4. Cell count and diff (repeat) or special studies
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25
Q

On a CSF analysis suggestive of bacteria, what would I see?

A
  1. Increased pressure 200-300
  2. Cloudy, purulent appearance
  3. Many PMNs >80%
  4. Low glucose <40
  5. High Protein >100
  6. Elevated lactate (>= 31.53) (additional study)
  7. Decreased CSF:serum glucose ratio < 0.4 (additional study)

Bacteria eat glucose so glucose is low, and then they poop out protein.

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26
Q

On a CSF analysis suggestive of viral infection what would i see

A
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27
Q

what lab studies do we order to work up bacterial meningitis

A
  • CBC - PMN leukocytosis (left shift)
  • CMP - assess liver/kidney fxn for abx
  • coag panel to differentiate who needs FFP or platelets after LP
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28
Q

What kind of illness can be negative on CSF fluid?

A

Tick-borne diseases (Lyme and Ehrlichiosis)

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29
Q

What could MRI show in terms of differentials for meningitis?

A
  • Brain Abscess
  • SAH
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30
Q

When is ABX given in terms of LP?

A

After the LP UNLESS the LP is delayed.

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31
Q

What is step 1 of empiric therapy for bacterial meningitis? what is the purpose of this step?

A
  • Dexamethasone given to ALL pts 0-20 min prior to ABX
  • prevents release of inflammatory cytokines initiated by antibiotics when they act on bacterial cell wall
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32
Q

For a healthy patient that is less than 50 yo, what is the empiric ABX for bacterial meningitis?

A
  • Rocephin (can use cefotaxime or cefepime)+
  • Vanco+
  • Acyclovir+ (given to cover HSV encephalitis)
  • additional empiric therapy if indicated

Do all 3 until a CSF analysis returns.

  • Rocephin can be subbed for ceftazidime or meropenem for neurosurg patients to cover p. aeruginosa.
    Roc the van cycle
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33
Q

What is the alternative to rocephin in neonates?

A

Cefotaxime + ampicillin

Rocephin causes hyperbilirubinemia
amplified taxes

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34
Q

When is ampicillin indicated as additional therapy for bacterial meningitis?

A
  • Cover listeria
  • indicated in < 1 month old or > 50 yo
  • also in Immunocompromised patients (includes preggo)
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35
Q

When is doxycycline indicated as additional therapy for bacterial meningitis?

A

During tick season

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36
Q

When is metronidazole indicated as additional therapy for bacterial meningitis?

A

G- anaerobes from sinusitis, otitis, or mastoiditis

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37
Q

What should we do to manage increased ICP?

A
  • Elevation of the patient’s head to 30deg
  • Intubation with hyperventilation
  • Mannitol (osmotic diuretic to reduce fluid)
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38
Q

What bacteria requires the longest duration of ABX therapy in bacterial meningitis?

A

Listeria (21 days)

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39
Q

When is repeat CSF analysis indicated in bacterial meningitis?

A
  • No improvement after 48 hrs of appropriate therapy
  • Microorganisms resistant (2-3 days after initiation of therapy)
  • Persistent fever > 8 days (without any other known cause)
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40
Q

If CSF cultures are positive on repeat, what should we do with our ABX?

A

Adminster them intrathecally or intraventricularly.

A repeat culture should be sterile ideally.

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41
Q

How does mortality vary in bacterial meningitis?

A
  • Highest < 1 year
  • Low in midlife
  • Increases in old age
42
Q

What is the PPE isolation for bacterial meningitis?

A

Droplet

gotta wear mask, eye prot, gown and gloves

43
Q

When do we do prophylaxis for bacterial meningitis and what is the treatment?

A
  • Close exposure to H flu meningitis
  • Rifampin 4 days

if allergic to rifampin contact ID

44
Q

What is considered contact for H flu meningitis?

A

Contact for 5/7 days for 4 hours for an index patient.

  • Anyone exposed to someone < 2yo
  • Anyone exposed to someone < 4yo and lives with them
  • Anyone exposed to someone that is not vaccinated against Hib
45
Q

What is chemoprophylaxis for N. menigitiditis?

who is included in phrophylactic treatment?

A

2 days of rifampin for any close exposures.

  • prolonged >8hr.exposure in <3ft proximity
  • direct exposure to oral secretions
  • exposure 7 days prior to onset of symptoms up through 24 hrs after initiation of abx
46
Q

What is the chemoprophylaxis for GBS meningitis?

A
  • Vaginal/anal swab at 35-37 weeks gestation
  • IV PCN during vag delivery to treat
  • preop neurosurgical prophylaxis is also indicated!!!
47
Q

What is the #1 way to prevent meningitis?

A
  • Pneumococcal vaccine
  • MenB and MenACWY
  • Hib
48
Q

What is the MCC of viral/aseptic meningitis?

A

Enteroviruses

49
Q

What are the risk factors for viral meningitis?

A
  • Infants < 1 mo
  • Immunodeficient patients
  • Exposure
  • Travel to endemic west nile, lyme, or other ticks
  • Sexual exposure (HSVs, HIV, syphilis)
50
Q

How does viral meningitis typically present?

A
  • Less severe version of bacterial
  • SHOULD NOT SEE focal neuro deficits

sHA, nuchal rigid, photophbia, pain w EOM, constutional, diminished LOC

51
Q

What specific findings are related to certain viruses for viral meningitis?

A
  • Diffuse maculopapular exanthem: entero, HIV, syphilis
  • Parotitis/orchitis: mumps in unvaccinated
  • Genital/oral lesions: HSV or syphilis
  • Thrush: HIV
  • Asymmetric flaccid paralysis: West Nile
52
Q

What additional study should be ordered in viral meningitis suspicion?

A

PCR tests for every individual virus

Usually start with enterovirus

53
Q

How does WBC count vary in viral meningitis?

A

Elevated but not as high as bacterial because it is predominantly lymphocytes.

54
Q

What lab test may be elevated specifically in mumps?

A

Amylase (due to parotitis)

55
Q

What viruses should NOT be tested serologically?

A
  • HSV
  • VZV
  • CMV
  • EBV

Everyone has exposure to these usually.

reminder: viral serology tests for IgM

56
Q

When is imaging indicated for viral meningitis?

A
  • altered LOC
  • Seizures
  • Focal neurologic s/s
  • atypical CSF profile
57
Q

Who do we treat empirically for suspected viral meningitis?

A
  • Elderly
  • Immunocompromised
  • Strong early suspicion of bacterial meningitis (err on the side of caution)
58
Q

If we have a patient that we suspect viral meningitis but their CSF is indeterminate after analysis, what can we do?

A
  • Administer empiric ABX after getting cultures
  • Observe for 24 hrs without giving ABX and repeat CSF in 6-24 hours.

either or

59
Q

What are the two viruses that require acyclovir for viral meningitis?

A
  • HSV
  • VZV

Newborns require the longest duration of antivirals

60
Q

What vaccines help prevent viral meningitis?

A
  • IPV
  • MMR
  • Varicella Zoster
61
Q

what is encephalitis?
what is it called if meninges are involved?
What is it called if spinal cord/nerve roots are involved?

A
  • encephalitis - inflammation of brain parenchyma
  • meningioencephalitis - meningial involvement
  • encephalomyelitis/encephalomyeloradiculitis - spinal cord/nerve root involvement
62
Q

What is the MC etiology for encephalitis?

A

Viral (HSV, VZV, EBV)

63
Q

What environmental factor might suggest amebic encephalitis?

A

Warm, freshwater area

64
Q

What environmental factor might suggest toxoplasmosis induced encephalitis?

A

Cat litter

65
Q

What is the primary difference between encephalitis and meningitis?

A

Encephalitis has more neurologic symptoms, but varies depending on the area inflammed.

66
Q

what is the clinical presentation of encephalitis?

A

ones i think stand out:
* fever
* seizures
* psychotic s/s (hallucination, personality/behavioral changes)
* focal neurologic signs (speech/hearing probs, mem loss, paralysis)
* Involvement of HPA axis ( hypothermia, diabetes Insip, SIADH)

no stand out: HA, NV, altered LOC

67
Q

what is the clinical presentation of neonatal or young infants with encephalitis

A
  • fever
  • poor feeding
  • irritablity
  • seizure
  • decreased perfusion
68
Q

What S/S suggest poor perfusion?

A
  • Slow cap refill
  • Cool extremities
  • Decreased urine output
  • Decreased level of altertness
69
Q

What findings would suggest a neonate has a HSV infection?

A
  • Herpetic lesions (face)
  • Keratoconjunctivitis
  • Oropharyngeal lesions
70
Q

What is the primary diagnostic test for encephalitis?

A

CSF PCR tests for individual viruses

CSF analysis should be same as viral meningitis.

71
Q

What CT/MRI findings suggest HSV etiology?

A

Focal findings on CT/MRI

90% of HSV encephalitis have focal findings.

72
Q

What do EEG abnormalities suggest for encephalitis etiology?

A

HSV

>75% of HSV encephalitis shows EEG abnormalities

73
Q

When is a brain biopsy indicated?

A

All of the 3:

  1. Focal abnormality on MRI
  2. Negative CSF/PCR
  3. Deterioration despite acyclovir and standard therapy.
74
Q

when would you order these additional labs and what would they show in encephalitis
- electrolyes
- glucose
- BUN/Cr
- LFT
- PT/PTT

A
  • electrolyes for abnormalities if dehydrated or SIADH
  • glucose to compare CSF glucose or r/o hypoglycemia
  • BUN/Cr to assess hydration status, end organ damage and renal function for med dose adjustments
  • LFT to assess for end organ damage or med adjustment
  • PT/PTT assess need for platelet or FFP transfusion
75
Q

What CSF finding is characteristic of amebic infection?

A

Motile trophozoites seen in wet mount of fresh, warm CSF.

76
Q

what will be seen in the CSF of autoimmune encephalitis?

A

specific autoantibodies

77
Q

What is the primary anticonvulsant for encephalitis?

A

Lorazepam

For acute treatment

78
Q

What is secondary prevention of seizures in encephalitis accomplished with?

A

Phenytoin or Fosphenytoin

Prevention only.

79
Q

What are the neuro checks?

A
  • LOC
  • A/O
  • pupil check
  • facial symmetry
  • tongue midline
  • speech clarity
  • sensation
  • grasp strength
  • strength and ROM of UE and LE
80
Q

What is empiric antiviral therapy for encephalitis?

A

IV acyclovir for 21 days

Within 30 minutes

81
Q

When is definitive antiviral therapy indicated for encephalitis?

A
  • HSV
  • Severe VZV/EBV
82
Q

When should CSF be repeated for encephalitis?

A
  • Repeat if they were PCR +.
  • If repeat is positive, then remain on therapy
83
Q

What is a brain abscess?

A

Uncommon, focal, suppurative infection within brain parenchyma and surrounded by a capsule.

Non-encapsulated is cerebritis

84
Q

What are the common etiologies for brain abscess?

A
  1. Direct spread (otitis media and mastoiditis are MC)
  2. Hematogenous (25%)
  3. Trauma/Surgery (30%)
85
Q

What is the MC symptom in brain abscess?

A

Gradual HA

>75% of pts. gradual over 10 days

86
Q

What are the 3 common abscess locations that produce focal neurological deficits?

A
  • Frontal lobe: Hemiparesis
  • Temporal lobe: Aphasia/dysphasia
  • Cerebellar: nystagmus/ataxia

present in >60% pts

87
Q

What are the common S/S of a brain abscess?

A
  1. HA 75%
  2. Focal neurologic deficits 60%
  3. Fever 50%
  4. New onset seizure
  5. S/S of increased ICP (papilledema, change in LOC, confusion)
88
Q

What imaging is used to workup a brain abscess?

A

CT or MRI WITH contrast

MRI preferred but not typically as readily available

CT shows area of hypodensity surrounded by ring enhancement and edema
MRI shows hypodense center surrounded by edema

89
Q

what are the following labs used for in brain abscess
CBC
CMP
Blood cultures

A

CBC - elevated WBC
CMP - assessing renal and liver fxn for med doses
blood cultures - x2 prior to abx to cater tx

90
Q

How are ABX of brain abscess given?

A

CT/MRI guided stereotactic needle aspiration

must get C&S of the abscess aspirate to guide ABX therapy

91
Q

Lack of what sign may suggest brain tumor over brain abscess?

A

Fever

More likely to be a solid mass

92
Q

What is the empiric treatment for community acquired brain abscess?

A
  • IV Rocephin + metronidazole
  • Drain abscess
93
Q

What is the empiric treatment for head trauma or neurosurgery related brain abscess?

A
  • Ceftazidime + Vanco
  • Meropenem + Vanco
  • Drain abscess
94
Q

When are steroids indicated for brain abscess?

A

Significant peri-abscess edema with associated mass effect and increased ICP

Steroids prevent encapsulation.

95
Q

What are the indications to NOT drain a brain abscess?

A
  • Inaccessible abscess
  • Small < 3cm or non-encapsulated
  • Unstable condition
96
Q

When is it indicated to completely excise an abscess?

A

Multiloculated or aspiration

97
Q

What is the overall treatment for a brain abscess?

A
  • Prophylaxis for seizures
  • Empiric parenteral ABX therapy
  • Drain abscess
98
Q

What is the clinical course of a brain abscess?

A
  • 6-8 weeks of parenteral ABX
  • Serial MRI or CT monthly or 2x monthly
  • Prophylactic anticonvulsant for 3 months minimum (until EEG is normal)
99
Q

What suggests poor prognosis for brain abscess?

A
  • Rapid progression of infection prior to admission
  • Severe mental status changes on admission
  • Stupor or coma (Extremely bad)
  • Rupture into ventricle (Extremely bad)
100
Q

How common are sequelae in brain abscess survivors?

A

20% of survivors

Clin Med B 2 (44 decks)

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