Download Infection of CNS.doc

Infection of CNS
Part One: Each item below contains a question or incomplete
statement followed by suggested responses. Select the one best
response to each question.
1. Which is the commonest form of infectious disease in CNS?
a. Tuberculous meningitis
b. Herpes aimplex virus encephalitis
c. Cryptococcal meningitis
d. Herpes zoster virus
e. Cytomegalovirus encephalitis
2. Which drug is the first choice when diagnosed with Cryptococcal
meningitis?
a. Amphotericin B
b. Acyclovir
c. Rifampin
d. Isoniazid
e. Dexamethasone
3. An obstruction in the interventricular foramen would interfere with the
flow of cerebrospinal fluid into?
a. Lateral ventricle
b. Third ventricle
c. Fourth ventricle
d. Subarachnoid space of the spinal cord
e. All above is wrong
4. Herpes simplex virus encephalitis CT change is?
a. Hypodensity of the affected areas in one or both temporal lobes
b. A wide range of high density area under the white matter
c. High density of the affected areas in one or both temporal lobes
d. Multiple hypodensity of the affected areas in Basal ganglia region
e. No abnormal performance
5. Which structure does not belong with the others?
a. Pons
b. Midbrain
c. Thalamus
d. Medulla
e. All above is wrong
6. Neuron cell bodies are located in all but?
a. Horns of spinal cord
b. Meninges
c. Basal nuclei
d. Cortex
e. All above is wrong
7. Which drug is the first choice when diagnosised with Herpes simplex
virus encephalitis?
a. Amphotericin B
b. Acyclovir
c. Rifampin
d. Isoniazid
e. Dexamethasone
8. Which of the following is not associated with cerebrospinal fluid?
a. Choroid plexus
b. Cervical plexus
c. Lateral ventricle
d. Subarachnoid space
e.All above is wrong
9. The cranial neuropathy most commonly found with Lyme disease is
that associated with damage to cranial nerve?
a. III
b. V
c. VII
d. IX
e. XII
10. The CSF in persons with multiple sclerosis will typically exhibit?
a. Glucose content of less than 20% of the serum content
b. Persistently elevated total protein content
c. Persistently elevated immunoglobulin G (IgG) content
d. Mononuclear cell counts of greater than 100 cells per µL
e. Erythrocyte counts of greater than 10 cells per µL
11. A 17-year-old right-handed boy has had infectious meningitis 8 times
over the past 3 years. He has otherwise been generally healthy and
developed normally. Recurrent meningitis often develops in persons
with?
a. Otitis media
b. Epilepsy
c. Multiple sclerosis
d. Whipple’s disease
e. Cerebrospinal fluid (CSF) leaks
12. Localization of an encephalitis to the medial temporal or orbital
frontal regions of the brain is most consistent with?
a. Treponema pallidum
b. Varicella zoster virus
c. Herpes simplex virus
d. Cryptococcus neoformans
e. Toxoplasma gondii
13. Neuroimaging of the brain before attempting a lumbar puncture is
advisable in cases of acute encephalitis because?
a. The diagnosis may be evident on the basis of magnetic resonance
imaging (MRI) alone
b. Massive edema in the temporal lobe may make herniation
imminent
c. The computed tomography (CT) picture may determine whether a
brain biopsy should be obtained
d. Shunting of the ventricles is usually indicated, and the imaging
studies are needed to direct the placement of the shunt
e. It may establish what pathology is responsible
14. The patient dies after a severe bout of aspiration pneumonia. Autopsy
of her brain reveals extensive loss of granule cells in the cerebellum and
other changes most obvious in the cerebellar cortex. Fine vacuoles give
the brain a spongiform appearance. No senile plaques are evident. The
patient could have acquired this progressive disease through?
a. Sexual intercourse
b. A blood transfusion
c. Consumption of raw fish
d. An upper respiratory infection
e. Growth hormone treatment
15. A patient has a disorder of the central nervous system. Which part of
the system could be involved?
a. Nerves in the forearm
b. Nerves to the heart
c. Spinal cord
d. Sympathetic neurons
e. All above is wrong
16. Which of the following are true statements relating to the meninges?
a. The dura mater is composed of a dense fibrous connective tissue.
b. The dura mater around the brain is single-layered.
c. Venous sinuses occur between the two dural layers around the
spinal cord.
d. The most superficial meninx is the arachnoid membrane.
e. All above is wrong
Items 17-18
An 82-year-old previously healthy woman with a recent upper respiratory
infection presents with generalized weakness, headache, and blurry vision.
For the past 2 weeks she has had upper respiratory symptoms that started
with a sore throat, nasal congestion, and excessive coughing. She went to
her primary care doctor 4 days ago and was diagnosed with sinusitis. She
was given a prescription for an antibiotic and took it for 2 days, then
stopped. She thereafter had chills, lightheadedness, vomiting, blurry
vision, general achiness, and a headache that started abruptly and has not
gotten better since. Other than blurry vision, she has not had any other
visual symptoms. The blurry vision remains when she closes either eye.
She also has eye tenderness with movement and mild photosensitivity.
She has no drug allergies. Exam findings include temperature of 102.5°
F, nuchal rigidity, and sleepiness.
17. The next most appropriate action in this case is which of the
following?
a. Get a brain MRI, then perform a lumbar puncture
b. Give the patient a prescription for oral azithromycin and let her go
home
c. Immediately give intravenous ceftriaxone plus ampicillin
d. Immediately start intravenous acyclovir
e. Obtain cerebrospinal fluid and blood cultures and observe the
patient until the results come back
18. The next day the patient’s spinal fluid cultures begin growing Listeria
monocytogenes. The drug of choice in this case now is?
a. Penicillin G
b. Ampicillin plus gentamicin
c. Tetracycline
d. Ceftriaxone
e. Rifampin
Items 19-20
A 31-year-old homosexual man has had headache, sleepiness, and poor
balance that have worsened over the past week. The patient is known to
be HIV-seropositive, but has done well in the past and has not seen a
doctor in over 1 year. On examination, his responses are slow and he has
some difficulty sustaining attention. He has a right hemiparesis with
increased reflexes on the right. Routine cell counts and chemistries are
normal.
19. Of the following, which is the most appropriate thing to do next?
a. Get a head CT with contrast
b. Get a noncontrast head CT
c. Perform a lumbar puncture
d. Start antiretroviral therapy
e. Start intravenous heparin
20. A CT scan reveals several rim-enhancing lesions with minimal mass
effect. An appropriate investigation at this point would be to?
a. Get a cerebral angiogram
b. Order a ventricular cerebrospinal fluid (CSF) aspiration
c. Perform a lumbar puncture and include cerebrospinal fluid for
Epstein-Barr virus (EBV) PCR in tests ordered
d. Stop all antiretroviral therapy
e. Treat with intravenous acyclovir
Part Two: Fill in the blanks
1. HSE’s most Pathogen is
2. Usually
and
?
are the two lobes invaded by the
herpes simplex virus.
3. The most widely used drug for HSE is
.
4. The most important diagnosis examination for infection of CNS
is
5.
.
and
are the commonest pathogen found in
Community-acquired pathogens in adults.
6. Tuberculous Meningitis can present with basal inflammation and
fibrosis and compress cranial nerves，especially
7. Neurosyphilis is treated by
8. The
pathogens
ways:
9.
reach
.
.
the
,
intracranial
,
structures
in
three
.
is a chronic infection disease, which is usually caused by
the acid-fast organism M.tuberculosis.
10. For severe patient of HSE,
can be used to control
inflammation and swelling in clinic.
Part Three: Definitions
1. HSE
2. Meningeal irritation sign
3. Nuchal rigidity
4. Kerning’s sign
5. Brudzinski’s signs
Part Four: General questions
1. Comparison of CSF in different types of meningitis (Bacterial VS
Viral)
2. What are the classic trials of symptoms of Bacterial Meningitis?
3. What is the treatment principle of bacterial meningitis?
4. Broadly, infections of CNS can be categorized clinically under 3
heading, what are they?
5. What is pathology of Herpes Simplex Encephalitis?
Part Five: Case analysis
A 24-year-odd woman was taken to our hospital because of headache,
vomiting and psychosis for 5 days. Ten days before, she had experienced
some flu-like symptoms which lasted several days. She had an
unremarkable medical history. In the emergency room, she had a
generalized tonic clonic seizure. On examination she had a temperature of
37.9℃ and was confused, uncooperative. Right Babinski’s sign was
positive, no neck stiffness, EEG demonstrated left-sided suppression and
slowing in the background activity. Brain MRI (T2WI and FLAIR) scans
showed high signal in both temporal lobes and right insula. Viral studies
including serum HSV antibodies and CSF cultures were all negative; CSF
analysis revealed an opening pressure of 210 mmH2O, CSF glucose 3.48
mmol/L at a time when her blood glucose was 5.8 mmol/L; protein 0.75
g/L and 50 WBC/mm3 with 65% polymorphonuclear cells.
.
1. What is the most likely diagnosis?
2. What laboratory tests and imaging studies are required for confirming
the diagnosis?
3. What is the most appropriate treatment for this condition?
Answers
Part One: Choice questions
1 to 5: b a b a d
6 to 10: b b b c c
11 to 15: e c b e c
16 to 20: a a b a c
Part Two: Fill in the blanks
1. HSV
2. frontal lobe, temporal lobe
3. acyclovir
4. CSF
5. streptococcus pneumonaie, Neisseria meningitidis
6. CN 6
7. penicillin
8. hematogenous spread, by extension from cranial structures, retragrade
from neural stem
9.Tuberculous Meningitis
10. corticosteroids
Part Three: Definitions
1. HSE：The encephalitis caused by HSV is the commonest form of
infectious disease in CNS.HSV most frequently implicates the
cerebrum frontal lobe, the temporal lobe and the limbic system, and
causes the brain tissue hemorrhagic necrosis and (or) the allergic brain
lesion, therefore HSV encephalitis (HSE) is also called as the acute
necrotic encephalitis, the hemorrhagic encephalitis or acute inclusion
body encephalitis.
2. Meningeal irritation sign: It is the inflammation of Meningeal,
performed as nuchal rigidity, Kernig’s sign, Brudzinsik’s signs.
3. Nuchal rigidity：Nuchal rigidity is the inability to flex the head
forward due to rigidity of the neck muscle; if flexion of the neck is
painful but full range of motion is present, nuchal rigidity is absent.
4. Kernig’s sign：Kernig’s sign elicits both resistance and hamstring
muscle pain when the examiner attempts to extend the knee while the
hip and knee are both flexed 90degrees. This may indicate
subarachnoid hemorrhage or meningitis.
5. Brudzinski’s signs：The most commonly used sign (Brudzinski’s
signs) is the appearance of involuntary lifting of the legs in meningeal
irritation when lifting a patient’s head off the examining couch, with
the patient lying supine.
Part Four: General questions
1. Comparison of CSF in different types of meningitis (Bacterial VS
Viral)
⑴ Bacterial meningitis: CSF pressure is elevated in approximately 90%
of cases, and the appearance of the fluid ranges from slightly turbid to
grossly purulent. CSF white cell counts of 1,000 to 10,000/µL are usually
seen, consisting chiefly of polymorphonuclear leukocytes, although
mononuclear cells may predominate in Listeria monocytogenes
meningitis. Protein concentrations of 100 to 500 mg/dL are most common.
The CSF glucose level is lower than 40 mg/dL in approximately 80% of
cases and may be too low to measure. Gram-stained smears of CSF
identify the causative organism in 70% to 80% of cases. CSF culture,
which is positive in approximately 80% of cases, provides a definitive
diagnosis and allows determination of antibiotic sensitivity.
⑵ Viral meningitis: The viral meningitis shows increased pressure,
lymphocytic or mixed lymphocytic and polymorphonuclear pleocytosis
(50～100 white blood cells/mL), mild protein elevation, and normal
glucose. Red blood cells, xanthochromia, and decreased glucose are seen
in some cases. The virus generally cannot be isolated from the CSF, but
can be detected by the polymerase chain reaction and serologic testing.
2.What are the classic trial of symptoms of Bacterial Meningitis?
⑴Fever
⑵Headache
⑶Meningeal irritation sign
3.What is the treatment principle of bacterial meningitis?
⑴ If the CSF is not clear and colorless, antibiotic treatment is started
without delay. The initial choice of antibiotics is empirical, based on the
patient’s age and predisposing factors. Therapy is adjusted as indicated
when the Gram stain or culture and sensitivity results become available.
⑵Lumbar puncture can be repeated to assess the response to therapy.
⑶ Dexamethasone, given immediately before the onset of antibiotic
treatment and continued for 4 days. Also reducing intracranial pressure,
respiratory care, treatment of seizures and preventing complications.
4.Broadly, infections of CNS can be categorized clinically under 3
heading, what are they?
⑴Meningitis
⑵Spinal Meningitis
⑶Encephalitis or meningoencephalitis
5.What is pathology of Herpes Simplex Encephalitis?
Hemorrhagic necrosis often accompanied by a substantial amount of
edema, is seen in the temporal lobe, limbic system and frontal lobes. At
acute stage of the disease, intranuclear eosinophilic in clusions (Cowdry
A inclusions) can be found in neurons and glial cell, and lymphocytes and
plasma cells also can be seen infiltration surrounding vessels.
Part Five: Case analysis
1. HSE
2. CSF and MRI
3. Early diagnosis and treatment are keys to reduce mortality of the
disease, including active antiretroviral therapy, reducing intracranial
pressure, respiratory care, treatment of seizures and preventing
complications. The most effective drug is acyclovir, given intravenously
at a dosage of 10~15mg/kg q8h.