LABS FOR NEURO DISEASES Flashcards
If the pressure proves to be very high-over____________—one should
obtain the smallest necessary sample of fluid and then,
according to the suspected disease and patient’s condition, administer mannitol or another hyperosmolar agent
400 mm HG
Dexamethasone or an equivalent corticosteroid may
generally also be given in an ___________ in order
to produce a sustained reduction in intracranial pressure
initial intravenous dose of
10 mg, followed by doses of 4 to 6 mg every 6 h
When in cisternal puncture indicated?
spinal block requiring a sample of
cisternal fluid or for myelography above the lesion.
Warming of the analgesic
by rolling the vial between the palms seems to diminish
the _______
burning sensation that accompanies cutaneous
infiltration.
The puncture is usually
easiest to perform at the L3-L4 interspace, which corresponds
in many individuals to the________
axial plane of the
iliac crests, or at the interspace above or below
______ during the insertion of
the needle indicates that it is placed too far laterally
Sciatic pain
L P has few serious complications . The most common
is _______, estimated to occur in one-third of
patients, but in severe form in far fewer.
headache
The pain is presumably the result of a _____________ from leakage of fluid at the puncture site and _____________as the patient assumes the erect posture.
reduction of CSF pressure
tugging on cerebral and dural vessels
Bleeding into the spinal meningeal or epidural
spaces after lumbar puncture can occur in patients who
are taking anticoagulants (generally with an international
normalized ratio _________, or impaired platelet function (alcoholism,
uremia) .
[INR] > 1 .4), have low platelet counts
<50,000/mm3
In the normal adult,
the opening pressure varies from ________
100 to 180 mm Hp, or
8 to 14 mm Hg
In an adult, a pressure of
________ indicates intracranial hypotension,
generally caused by leakage of spinal fluid or systemic
dehydration.
50 mm H20 or below
The presence of a spinal subarachnoid block was
in the past confirmed by jugular venous compression
_____________
(Queckenstedt test, which tests for a rapid rise in CSF pressure within a few seconds after application of the pressure on the vein).
The presence of red blood
cells imparts a hazy or ground-glass appearance; at least
________
must be present to detect this change.
The presence of
______________, depending on the amount of blood;
centrifugation of the fluid or allowing it to stand causes
sedimentation of the RBCs
200 red blood cells (RBCs) per cubic millimeter (mm3)
1,000 to 6,000 RBCs per cubic millimeter imparts a hazy
pink to red color
In subarachnoid hemorrhage, the
RBCs begin to hemolyze within a few hours, imparting
a pink-red discoloration _______
(erythrochromia) to the
supernatant fluid;
only with large amounts of venous
blood (RBC more than 100,000/mm3) will the supernatant
fluid be faintly xanthochromic due to__________
contamination
with serum bilirubin and lipochromes
The pigments that discolor the CSF following subarachnoid
hemorrhage are __________
oxyhemoglobin, bilirubin,
and methemoglobin
Oxyhemoglobin
appears within several hours of hemorrhage, becomes
maximal in approximately ________, and diminishes over
a _______
36 h
7- to 9-day period.
Bilirubin begins to appear in___________ and increases in amount as the oxyhemoglobin
decreases.
2 to
3 days
___________
(through hemoglobin breakdown products, particularly
oxyhemoglobin) also impart a yellow tint to the CSF, as
do blood clots in the subdural or epidural space of the
cranium or spinal column
Hypercarotenemia and hemoglobinemia
_________does not enter the
CSF because a low renal threshold for this pigment permits
rapid clearing from the blood
Myoglobin
During the first month of life, the CSF may contain a s mall
number of _________
mononuclear cells
The protein content of CSF from the basal cisterns is _______and that from the ventricles is ______
10 to 25 mg/ dL
5 to 15 mg/ dL.
In children, the protein concentration is somewhat
lower at each level ______
( <20 mg/ dL in the lumbar subarachnoid space).
If the serum protein concentrations
are normal, the CSF protein should increase by about __________RBCs provided that the same tube of CSF is
used in determining the cell count and protein content
1mg per 1,000
Values in the lumbar CSF of 1,000 mg/ dL or
more usually indicate a block to CSF flow; the fluid is then
deeply yellow and clots readily because of the presence of fibrinogen; a combination called _______
Froin syndrome
The gamma globulin fraction
in CSF is approximately _______ of that in serum.
70 percent
There are other notable differences between the protein
fractions of CSF and plasma. The CSF always contains a
________ and the plasma does not
prealbumin fraction
The concentration of tau
protein and in particular the ratio of _________
has found use in the diagnosis of Alzheimer disease
tau to beta-amyloid,
The most important
is IgG, which may exceed 12 percent of the total CSF
protein in diseases such as multiple sclerosis, ________
neurosyphilis,
subacute sclerosing panencephalitis and other chronic viral meningoencephalitides
Certain enzymes that originate in the
brain, especially the brain-derived fraction of creatine
kinase (CK-BB) but also __________ are found
in the CSF after stroke, global ischemic hypoxia, or
trauma, and have been used as markers of brain damage
enolase and neopterin,
Other special markers such as elevation
of the 14-3-3 protein, which has some diagnostic
significance in __________, B-microglobulin in ______________, __________ in traumatic
and other severe brain injuries, and alpha fetoprotein in
embryonal tumors of the brain
prion disease
meningeal lymphomatosis
neuron specific enolase
abnormal. After
the intravenous injection of glucose, ________ are required
to reach equilibrium with the CSF; a similar delay follows
the lowering of blood glucose.
2 to 4 h
Low values of CSF glucose (hypoglycorrhachia) in the presence of pleocytosis usually indicate _________
bacterial, tuberculous, or fungal
meningitis,
As a rule, viral infections of the meninges and brain do not lower the CSF glucose, although low glucose values have been reported in a small number of patients with ___________
mumps meningoencephalitis, and rarely in patients with herpes simplex and zoster infections.
false positive for CALAS
false-positive reaction is
obtained in the presence of high titers of rheumatoid factor
or antitreponemal antibodies,
false positive for Venereal Disease Research Laboratories
(VORL) slide flocculation test and rapid plasma reagin
(RPR) agglutination tes
false-positive reactions may occur
with collagen diseases, malaria, and yaws, or with contamination
of the CSF by seropositive blood
timing of highest sensitivity for PCR tests
These tests are most useful in the first week
of infection, when the virus is being reproduced and its
genomic material is most
Normally, the
pH of the CSF is approximately ________somewhat lower
than that of arterial blood, which is 7.41 .
7.31
The ammonia content of the CSF is __________
that of the arterial blood; it is increased in hepatic
encephalopathy, the inherited hyperammonemias, and
the Reye syndrome;
the concentration corresponds
roughly with the severity of the encephalopathy
one-third to onehalf
Elevations of _________are found in all of the portosystemic
encephalopathies including hepatic coma and the
Reye syndrome.
glutamine
lactic dehydrogenase,
especially isoenzymes 4 and 5, are elevated in
Bact Men
___________
is also elevated in cases of meningeal tumor infiltration,
particularly lymphoma,
Lactic dehydrogenase
IN CT With contrast, Intravenous contrast in generally withheld
if the glomerular filtration rate (GFR) is less than _____
30 mL/
min/ 1 . 73 m2;
MRI also provides images in any plane, but i t has the
great advantage over CT in using _____
nonionizing energy
and providing higher resolution views
Gradient-echo (GRE), or susceptibility weighted imaging (SWI), is especially sensitive to blood and its breakdown products that appear \_\_\_\_\_\_\_\_
hypointense
Preferential movement of water molecules
along a particular direction, for example, parallel to white
matter tracts, is referred to as _______
anisotropy
Pus-filled abscesses and hypercellular tumors
can also show DWI _________, reflecting the limitation
of free diffusion of water in these lesions
hyperintensity
_______has provided a means of
detecting regions of ischemic tissue, and to monitor the
elevated blood volume in certain brain tumors
Perfusion imaging
____________is a marker of neuronal integrity;
and is decreased in both destructive lesions and in
circumstances in which there is a reduction in the density
of neurons (e.g., edema or glioma that increases the
distance between neurons)
N-acetyl aspartate (NAA)
_________a marker of
membrane turnover, is elevated in some rapidly dividing
tumors.
Choline (Cho),
________ can be extracted from MRI
data and used as a surrogate for local cerebral metabolic
activity.
This blood oxygen leveldependent
(BOLD) signal
________ a technique which has evolved from PET, uses
isotopes that do not require a cyclotron for their production
Single-photon emission computed tomography
(SPECT),
Complication rate from angiography
Overall morbidity from
the procedure is approximately 2.5 percent, mainly in the
form of worsening of a preexistent vascular lesion or from
complications at the site of artery puncture
___________can be performed without
contrast, using the “time-of-flight” technique.
MR angiography
they allow an accurate localization of
the locus of maximal stenosis as reflected by the highest
rates of flow and turbulence
carotid duplex
The transcranial Doppler uses a_______
signal that is able to pass through the calvarial bone in
adults and then receives a frequency-shifted signal from
the blood flowing in the lumen of the basal vessels
2-MHz pulsed
One of the
most remarkable properties of evoked potentials is their
resistance to________, and-in comparison
with EEG activity-even damage of the cerebral
hemispheres.
anesthesia, sedative drugs
The interpretation of evoked potentials (visual, auditory,
and somatosensory) is based on the ________
prolongation of
the latencies of the waveforms after the stimulus, the
interwave latencies, and asymmetries in timing
light stimulus
flashing on the retina evokes a discernible waveform in the occipital lobes
occipital driving
response
BAEPs are a particularly sensitive means of detecting
lesions of the _______
eighth cranial nerve (vestibular
schwannoma and other tumors of the cerebellopontine
angle) and of the auditory pathways of the brainstem
___________consists of applying 5-per-second painless
transcutaneous electrical stimuli to the median, peroneal,
or tibial nerves and recording the evoked potentials (for
the upper limb) sequentially
SSEP
passage points of evoked potentials
Erb point above the clavicle,
over the C2 vertebra,
and over the opposite parietal cortex,
and(for the lower limb) over the lumbar roots of the cauda equina, the nuclei over the cervical spine, and the opposite parietal cortex
Delay between the stimulus site and the Erb point or the lumbar spine indicates _________
peripheral nerve disease
delay from the Erb point (or lumbar spine) to C2 implies an abnormality in the appropriate\_\_\_\_\_\_\_\_\_
nerve roots or, more frequently,
in the posterior columns;
The normal waveforms are
designated by the symbols _________
P (positive) and N (negative
