Infections of central nervous system

Question 1

What are the source of infectious agents in meningitis

Answer 1

Typically colonize nasopharynx and respiratory tract, then enter CNS

Question 2

What are three routes through which meningitis organisms enter the CNS

Answer 2

1.) Blood2.) Retrograde transport along cranial/peripheral nerves3.) Contiguous spread from sinusitis, otitis media, surgery, or trauma

Question 3

Two major classes of meningitis based on onset

Answer 3

Acute - hours to days onsetChronic - weeks to months onset

Question 4

What is chronic meningitis typically caused by

Answer 4

Mycobacteria, fungi, lyme disease, parasites

Question 5

Two major classifications of meningitis based on species involved

Answer 5

Bacterial and aseptic

Question 6

Bacterial: Causes of meningitis in neonates

Answer 6

Group B strep, E. coli, Listeria monocytogenes

Question 7

Bacterial: Causes of meningitis in children > 3 months

Answer 7

N. meningitis, strep pneumoniae, H. influenzae

Question 8

Bacterial: Causes of meningitis in adults ages 18 to 50

Answer 8

strep pneumoniae, N. meningitis, H. influenzae

Question 9

Bacterial: Causes of meningitis in elderly > 50 years

Answer 9

strep pneumo, N. meningitis, L. monocytogenes

Question 10

Bacterial: Complications of meningitis

Answer 10

Seizures, coma, brain abscess, DIC, respiratory arrest, subdural empyema

Question 11

Bacterial: Permanant damage of meningitis

Answer 11

Deafness, brain damage, hydrocephalus

Question 12

Aseptic: Viruses involved

Answer 12

HSV and enterovirus

Question 13

What do you do if you are uncertain it is aseptic meningitis

Answer 13

Treat like its bacterial meningitis

Question 14

What is the classic triad of acute bacterial meningitis

Answer 14

Fever, nuchal rigidity, and alteration in mental status

Question 15

What other symptoms, aside from the triad, occurs in bacterial meningitis

Answer 15

Headache (worse with lying down), nausea/vomiting, photophobia, rashes, increased ICP (papilledema), cranial nerve palsies

Question 16

What are two kinds of rashes you can see in meningitis and what species are they associated with

Answer 16

1.) Maculopapular rash with petechiae - N. meningitis2.) Vesicular lesions - HSV or varicella

Question 17

In how many patients is kernig’s sign and brudzinkksi’s sign present in meningitis

Answer 17

50%

Question 18

What is the first thing you must do if you suspect meningitis, and when is that contraindicated and replaced by something else first

Answer 18

LP for CSF examination and noting opening pressure, unless space occupying lesion or focal neurological signs, in which case do CT scan first

Question 19

What can be seen initially to naked eye of CSF examination before sending it

Answer 19

Cloudy = pyogenic leukocytosis

Question 20

What should CSF be examined for

Answer 20

WBC count, protein, glucose, gram stain, culture, cryptococcal antigen (or india ink)

Question 21

What should you see in CSF analysis of bacterial meningitis

Answer 21

Elevated WBC’s with high PMNs, low glucose, high protein, and positive gram stain in 75 to 80%

Question 22

What should you see in CSF analysis of aseptic meningitis

Answer 22

lymphocytic pleocytosis, protein normal, glucose normal, CSF normal looking

Question 23

What should you obtain before beginning any antibiotics in meningitis

Answer 23

Blood cultures

Question 24

Memorize CSF analysis

Answer 24

Page 370

Question 25

When should you initiate antibiotics in meningitis

Answer 25

Immediately after LP

Question 26

How do you decide what antibiotics to give to someone with meningitis

Answer 26

By their age

Question 27

What antibiotics should you give in meningitis:

Answer 27

Cefotaxime + ampicillin + vancomycin(aminoglycoside if less than 4 weeks old)

Question 28

What antibiotics should you give in meningitis: 3mo to 50 years

Answer 28

Ceftriaxone + vancomycin

Question 29

What antibiotics should you give in meningitis: >50 years

Answer 29

Ceftriaxone + vancomycin + ampicillin

Question 30

What antibiotics should you give in meningitis: impaired cellular immunity (HIV)

Answer 30

Ceftazidime + ampicillin + vancomycin

Question 31

What is the vaccination criteria for meningitis

Answer 31

>65 years = S. pneumoAsplenic = S. pneumo, N meningitis, H influenzaeImmunocompromised = meningococcus

Question 32

What should you do for all close contacts of meningitis patients

Answer 32

Prophylax - IM ceftriaxone of patients with meningococcus

Question 33

What is the care for aseptic meningitis

Answer 33

Supportive care - disease self-limitedMay reduce fever and analgesia

Question 34

What is the most common organism for encephalitis

Answer 34

Viral - herpes, arbovirus (West nile and eastern equine), enterovirus (polio) and others

Question 35

What are nonviral causes of encephalitis

Answer 35

Aspergillosis, toxoplasmosis, T cell lymphoma

Question 36

What specific kind of encephalitis are you at risk for with a CD4 count of less than 200

Answer 36

Toxoplasmosis

Question 37

What are some common risk factors for encephalitis

Answer 37

1.) AIDS2.) Immunosuppression3.) Underdeveloped countries4.) Mosquito exposure in endemic area5.) Rabies exposure in endemic area

Question 38

How does encephalitis progress

Answer 38

Starts off with headache, malaise, myalgiaThen in hours to days becomes more acutely ill

Question 39

What are signs and symptoms of encephalitis

Answer 39

Meningitis symptoms + altered sensorium (like delerium) + focal neurological signs

Question 40

How do you rule out nonviral causes of encephalitis

Answer 40

CXR, urine and blood culture, urine toxicology, serum chemistry

Question 41

What should be done in the first step in diagnosing viral causes of encephalitis

Answer 41

LP to examine CSF showing lymphocytosis with normal glucose, but cultures would be negative. CSF PCR is test of choice!

Question 42

What else can be done besides LP to see causes of encephalitis

Answer 42

MRI: Rules out neurological causes such as abscessIncreased signal in T2 in frontotemporal area = HSV encephalitis

Question 43

When is brain biopsy indicated in suspected encephalitis

Answer 43

Last resort - acutely ill patient with focal, enhancing lesion on MRI without clear diagnosis

Question 44

What is the main treatment for encephalitis

Answer 44

Supportive care, maybe intubate

Question 45

For what two viruses can you give antiviral therapy for in encephalitis

Answer 45

1.) HSV - acyclovir 2 to 3 weeks2.) CMV - ganciclovir/foscarnet

Question 46

What do you do if cerebral edema in encephalitis

Answer 46

Hyperventilation, osmotic diuresis, and steroids

Question 47

What species do you think of in AIDS and neutropenic patients

Answer 47

AIDS = toxoplasmosis, fungiNeutropenic = candida, aspergillus, zygomycosis

Question 48

What are normal levels for WBC count (cells/mm3), WBC differential, glucose, and protein

Answer 48

WBC count:

Question 49

What do you usually see in viral meningitis in CSF findings

Answer 49

Glucose greater than 45, protein less than 200, negative gram stain

Question 50

What do you usually see in bacterial meningitis in CSF findings

Answer 50

Glucose less than 34, protein greater than 220, leukocytes greater than 2000/uL, CSF neutrophils greater than 1180/uL (99% certainty)

Question 51

What should be used as empiric therapy for acute bacterial meningitis

Answer 51

Third generation cephalosporin (ceftriaxone), vancomycin, and ampicillin

Question 52

What is ampicillin used for empiric therapy of acute meningitis

Answer 52

Listeria monocytogenes

Question 53

Why is ceftriaxone used for empiric therapy of acute meningitis

Answer 53

Penicillin-resistant strep pneumo