Acute CNS Infections/Infectious Diseases

Question 1

clinical presentation, most common organisms for different age groups

Answer 1

x

Question 2

basic CSF profile (cell number and type, glucose, protein) for bacterial meningitis

Answer 2

x

Question 3

basic medical management for bacterial meningitis in different age groups

Answer 3

x

Question 4

the clinical features, most common viruses, basic CSF profile, and key diagnostic tests for viral meningitis and viral encephalitis

Answer 4

x

Question 5

basic clinical features, diagnostic tests, and initial antimicrobial therapy for patients with a focal suppurative CNS infection (e.g., brain abscess, empyema)

Answer 5

x

Question 6

Viral Infections of the CNS

Answer 6

Viral Meningitis

Viral Encephalitis

Question 7

_________ is an infection of the subarachnoid space (SAS)

Answer 7

Meningitis

Question 8

Inflammation in SAS

Answer 8

Increases BBB Permeability
Vasogenic edema & Increased ICP
Causes infarction from vasculitis
Interferes with CSF Circulation
Hydrocephalus

Question 9

Bacteria induce_____________

TNF-a, IL-1: Recruit PMNs, Reactive Oxygen Species add to vasogenic, cytotoxic edema

Answer 9

pro-inflammatory cytokines

Question 10

Bacterial MeningitisClinical Features

Classic Triad

Answer 10

Stiff Neck (Nuchal Rigidity)
Fever
Depressed Consciousness

Question 11

Bacterial MeningitisClinical Features, other

Answer 11

Headache
Other CNS Findings
Seizures
CN Palsies (III, VI, VII, VIII)
Focal Deficits (Hemiparesis, Gaze Pref., Ataxia)
Papilloedema in

Question 12

Meningeal Signs

Answer 12

Kernig’s sign, Brudzinski’s sign

Question 13

Kernig’s sign

Answer 13

supine patient, flex thigh to abdomen. Passive extension of leg, patient resists due to pain.

Question 14

Brudzinski’s sign

Answer 14

passive flexion of neck causes flexion of the hips & knees

Question 15

Lumbar Puncture Results Bacterial Meningitis

Answer 15

CSF pleocytosis 1000-5000/mm3 
Percentage neutrophils/PMNs ≥80%
Protein 100-500 mg/dL
Glucose ≤40 mg/dL
CSF-to serum glucose ratio ≤0.4

Question 16

What do you need prior to LP

Answer 16

Should have CT or MRI prior to lumbar puncture

Pts w/ ams, ↑ ICP signs, new sz (prevent herniation)

Question 17

Neonatal

Answer 17

Group B streptococcus (GBS)- 50%
Escherichia coli (E. coli)- 14%
Streptococcus pneumoniae (pneumococcus)- 9%
Neisseria meningitidis (meningococcus)-8%
Listeria monocytogenes- 4% and only in 1st 30 days

Question 18

Bacterial MeningitisMicrobiology: 2-23months

Answer 18

Group B Strep (Strep. agalactiae)
E. coli 
H. influenzae
Strep. pneumoniae
Neisseria meningitidis

Question 19

2-35yrs

`Bacterial MeningitisMicrobiology

Answer 19

Neisseria meningitidis (‘Meningococcus’) 50-60 %
Streptococcus pneumoniae (‘pneumococcus’) -25-30%

Question 20

> 35yrs

Bacterial Meningitis Microbiology

Answer 20

Streptococcus pneumoniae -50-70%
Neisseria meningitidis -10-25%
Listeria monocytogenes -5-10%
10-15% if >60 yrs

Question 21

Corticosteroid Recommendations- Bacterial Meningitis

Answer 21

Start Corticosteroid Therapy with or prior to 1st dose of antibiotics.

Continue therapy if pneumococcus identified.

Caution using corticosteroids in immune suppressed or individuals from non-industrialized, developing regions.

Question 22

Bacterial Meningitis and ICP

Answer 22

Patients with signs of increased ICP may benefit from insertion of an ICP-monitoring device.*

ICP > 20mmHg (~25cmH20) should be treated.

Appropriate treatment for increased ICP in bacterial meningitis is not known.

Question 23

Bacterial meningitis is a medical emergency and __________ should be started within 1 hour of entering the hospital or clinic.

Answer 23

empiric antibiotic therapy

Question 24

The ____________ determine the most likely causative organism and guide empiric therapy

Answer 24

age of the patient, CSF profile, and epidemiologic risks

Question 25

Imaging to evaluate for a CNS mass should not delay:

Answer 25

initiation of empiric antibiotic therapy.

Question 26

__________ in patients with bacterial meningitis may prevent hearing loss and improve outcomes in developed countries

Answer 26

Corticosteroids

Question 27

Viral Meningitis & Encephalitis s/s

Answer 27

Significantly Altered Mental Status, Focal Neurological Deficits, seizures all suggest brain parenchymal involvement (Encephalitis, Abscess/Empyema, etc.)

Question 28

Viral Meningitis organism

Answer 28

Enteroviruses | HSV-2

Question 29

Viral Encephalitis organism

Answer 29

WNV (west nile) | HSV-1

Question 30

Viral CNS InfectionCSF Profile

Answer 30

Lymphocytic Pleocytosis PMNs early in some (Repeat LP @24 hrs) Normal Glucose Normal or mildly elevated protein PCR positive (Enterovirus, HSV, CMV, EBV, VZV) CSF Serology (IgM) for WNV and other arboviruses

Question 31

Enteroviruses

Answer 31

Most common cause viral meningitis Fecal-oral transmission (Occ. Respiratory) Late Summer/early Fall Prevalence

Question 32

Enterovirus Clues

Answer 32

Rash, Pharyngitis/Herpangina, GI, Pleurodynia, Myocarditis, Pericarditis, Conjunctivitis

Question 33

Autoimmune Encephalitis

Answer 33

Anti-NMDA Receptor Encephalitis: | CSF profile looks like viral encephalitis

Question 34

Goal is to start Antibiotics within_____ of patient arrival in the emergency room

Answer 34

60 minutes

Question 35

ampicillin PLUS cefotaxime OR ampicillin PLUS aminoglycoside

Answer 35

Neonates:

Question 36

Ceftriaxone AND Vancomycin

Answer 36

Children (>2mo)/Adults

Question 37

Ceftriaxone AND Vancomycin AND Ampicillin

Answer 37

Adults >50

Question 38

Meropenem or Cefepime AND Vancomycin +/- Ampicillin

Answer 38

Immunocompromised/Nosocomial/Recent Head trauma/Neurosurgery

Question 39

Arboviruses

Answer 39

WNV

Question 40

WNV Human Infection “Iceberg"

Answer 40

10% fatal 20% fever 80% asymp

Question 41

WNV Meningoencephalitis

Answer 41

``` Fever, Headache, Nuchal Rigidity Nausea, Vomiting, Neck Pain, Myalgia Low Back Pain Tremor Parkinsonism-rigidity, bradykinesia, instability Myoclonus, opsoclonus-myoclonus Weakness: Flaccid paralysis Cranial Nerve Palsy (esp. facial weakness) Cerebellar Signs ```

Question 42

WNV Neuroimaging

Answer 42

Early: MRI often completely NORMAL Later: ~30% Abnormalities in deep gray nuclei Subtle, symmetric findings Most similar to JEV and SLE Thalamus, Basal Ganglia, Midbrain (Nigra), Brainstem Unlike HSV, HHV-6 : “Limbic encephalitis” Medial Temporal Lobe and Hippocampus

Question 43

CSF in WNV

Answer 43

Pleocytosis up to >2000 cells (mean ~250) PMNs can predominate & persist (4-7d) Reactive Lymphocytes (“plasma cells”, “Mollaret”) Elevated protein (50-250 mg/dL) Normal glucose WNV IgM diagnostic (does not cross BBB) +PCR diagnostic (sensitivity ~70%)

Question 44

_______ is the most common cause of sporadic encephalitis and West Nile virus is the most common cause of epidemic encephalitis in the US.

Answer 44

Herpes Simplex virus

Question 45

CSF PCR is a sensitive diagnostic tool for Herpes infections and ______ is the diagnostic test of choice for neuroinvasive West Nile virus.

Answer 45

CSF IgM

Question 46

Start empiric ________ in patients with suspected encephalitis as soon as possible

Answer 46

acyclovir

Question 47

Adult Clinical Evaluation Summary | Clinical Meningitis

Answer 47

Blood cultures + empiric treatment for bacteria +/- antiviral for HSVII LP: Viral (aseptic) or Bacterial CSF Profile May obtain imaging prior if indicated but often negative If viral: likely causes enterovirus, HSVII, WNV, VZV, etc.

Question 48

Adult Clinical Evaluation Summary | Possible Encephalitis

Answer 48

MRI: mass lesion or other cause of brain parenchymal involvement? LP: Viral or bacterial CSF Profile Empiric antiviral for HSVI +/- antibiotics (concern for severe meningitis start antibiotic 1st as per meningitis!!!)

Question 49

Herpes Simplex virus is the most common cause of sporadic encephalitis and _______ is the most common cause of epidemic encephalitis in the US.

Answer 49

West Nile virus