Gross blood due to subarachnoid hemorrhage

may disappear within 24 hours, but generally persists for

7–14 days.

Turbidity in CSF may result from large numbers of

leukocytes or bacteria and varies from slight opalescence

typical in tuberculous meningitis to the grossly purulent

appearance in some cases of pyogenic meningitis.

Turbidity is usually graded from 0 (crystal clear) to 4+

(newsprint cannot be seen though the tube).

Clotting in CSF may be seen Grossly in:

¾ Traumatic tap

¾ Markedly elevated CSF protein or

¾ Moderately elevated CSF protein in association with

tuberculous meningitis (cobweb coagulum).

Cell Counts

Diluting the Fluid

1. Draw Unna’s polychrome methylene blue to the ‘1’

mark in a RBC pipette and fill pipette to ‘101’ mark

with spinal fluid. This colors white cells blue and red

cells yellow.

2. Turbid fluid: When many cells are present (as in turbid

or purulent fluid), better counts are obtained with a

WBC pipette and WBC diluting fluid.

3. Bloody fluid: When significant numbers of red cells

are present in the fluid, the possiblity of traumatic

bleeding should be considered. Fresh RBCs are intact

with a smooth round margin. Older cells have crenated

appearance.

Count

Count 9 large squares in the counting chamber for both

RBCs and WBCs—the total multiplied by 1.1 gives the

number of cells per cubic mm.

Differential count: Centrifuge the CSF and make smears

from the sediment. Stain and count as for a blood smear.

Various Types of Cells in CSF

Large number of polymorphs → pyogenic meningitis due to:

¾ Neisseria meningitidis

¾ Haemophilus influenzae

¾ Pneumococci

¾ Streptococci

¾ Staphylococci

¾ Coliforms.

¾ Sometimes in viral meningitis or aseptic meningeal

reaction

¾ Rarely in intracerebral hematoma, fungal meningitis,

RISA injection, or following lumbar puncture with

detergent-contaminated needles.

Mixed Reaction (Neutrophils, Lymphocytes and

Monocytes) Occurs in:

¾ Subacute bacterial meningitis

¾ Tuberculous meningitis

¾ Mycotic meningitis

¾ Viral meningoencephalitis.

Monocytic and/or Lymphocytic Reaction is Seen in:

¾ Viral meningoencephalitis

¾ Multiple sclerosis

¾ Tuberculous

¾ Fungal meningitis

¾ Syphilitic

Blasts may be seen in leukemic cell infiltrates in the

meninges.

Abnormal malignant/benign cells in certain CNS

neoplasms.

Globulin Test

These are valueless if the spinal fluid is bloody.

1. Pandy’s test: Place 1–2 mL of a saturated solution of

phenol in a small test tube and add 1 drop of spinal

fluid. Cloudiness against a black background indicates

increased amounts of globulin. Report as 0, +, ++, +++

or ++++.

2. Ross Jones test: Carefully layer 0.5 mL clear spinal

fluid over 1 mL of saturated solution of ammonium

sulfate. A thin white ring appearing at the juncture of

the liquids, which disappears on mixing, indicates a

1+ reaction. Heavy cloudiness persisting after mixing

is a 4+ reaction.

Total proteins (Quantitative method of Dennis and

Ayer): Place 1.2 mL of clear spinal fluid, 0.8 mL of distilled

water, and 2 mL of 5% sulfosalicylic acid in a small test

tube and mix by inversion. Let stand for 5 minutes, then

read in a colorimeter against a known standard protein

suspension (make known suspension by mixing 2 mL of

a standard protein solution with 2 mL of 5% sulfosalicylic

acid). If the unknown is too heavy with protein, dilute and

compare. Consider dilution factor in the calculation.

Transmission standard _____________________________________ × 50 = mg of protein/100 mL of fluid Transmission unknown

Cerebrospinal and Other Body Fluids 385

Nowadays microprotein colorimetric biochemistry kits

are available for quicker and accurate analysis.

CSF electrophoresis shows prodominantly albumin.

In adults, levels of 60–75 mg% are considered slightly

increased, levels of 75–150 mg% moderately increased and

beyond 150 mg% are markedly increased.

Increase in CSF protein may occur with any lesion

causing injury to cerebral tissue or blood-brain barrier;

viral, tuberculous, mycotic, syphilitic or bacterial meningoencephalitis, polyneuritis, intracerebral hemorrhage,

degenerative disease, or aseptic meningeal reaction. Brain

tumors cause variable increases, depending upon their

location—gliomas deep in the pons or cerebrum may be

associated with normal levels, while acoustic neuromas

in tumors of the corpus callosum usually cause marked

increase in CSF protein. Other causes include diabetic

neuropathy, myxedema, heavy metal intoxication, isopropanol intoxication, hypercalcemia and diphenylhydantoin

(Dilantin) intoxication. Multiple sclerosis causes minimal

increase in CSF protein; whereas, cerebral thrombosis,

subdural hematoma and aseptic and viral meningitis

usually are associated with normal CSF protein.

Conditions that Elevate CSF Protein

Mild Elevation, to 300 mg%

Viral meningitis, neurosyphilis, subdural hematoma,

cerebral thrombosis, brain tumor, multiple sclerosis

(rarely > 100 mg%).

Electrophoretic Evidence of IgG

Multiple sclerosis, subacute sclerosing panencephalitis,

neurosyphilis.

Moderate or Pronounced Elevation

Acute bacterial meningitis, tuberculous meningitis, spinal

cord tumor, cerebral hemorrhage, intracranial tumor,

Guillain-Barré syndrome (ascending polyneuritis).

The term albuminocytologic dissociation refers to

increased CSF protein with normal or near normal CSF

cell count—classically seen in Guillain-Barré syndrome,

but it may also occur in subarachnoid block, brain tumor,

multiple sclerosis, cerebral thrombosis and various types

of polyneuritis.