otherwise from sediment of centrifuged CSF. All smears

should be stained with Gram’s stain. If no characteristic

bacteria are found, do an acid-fast stain and search for

mycobacteria (AFB) stain should also be done if a

pellicle forms on standing. An India ink preparation is

required for Cryptococcus. Immunofluorescent stains

can be used for Haemophilus influenzae and some

other organisms.

2. Cultures: Cloudy fluid should be streaked on chocolate

agar, Sabouraud’s agar, and agar plates and inoculated

into blood broth and thioglycollate medium. All media

are incubated at 37oC, some in candle jars (for CO2

atmosphere). Sediment of centrifuged fluid should

be cultured on special media for tubercle bacilli and

fungi and inoculated into guinea pigs. Mice should be

inoculated intraperitoneally if coccidioidomycosis is

suspected.

3. Virus isolation: This is possible only in very sophisticated laboratories and is helpful in aseptic meningitis

and arthropod-borne encephalitis.

Serologic Tests

One can do:

¾ VDRL using CSF in syphilis.

FIG. 12.1: Lange’s colloidal gold test

Cerebrospinal and Other Body Fluids 387

TABLE 12.1: CSF in differential diagnosis

Disease Initial pressure

mm H2O

column

Appearance Cells/cu mm Protein mg% Glucose

mg%

Colloidal

gold

Remarks

Normal 70–150 Crystal clear 0–8,

lympho’s

20–50 50–80 0000110000 In fasting afebrile

individuals

Acute purulent

meningitis

 ↑ Opalescent to

purulent clot

500–20,000

mostly

poly’s

50–1000+ 0–45 Variable Organism in sediment

or clot, culture positive

Tuberculous

meningitis

 ↑ Opalescent

fibrin web,

pellicle

10–500

mostly

lympho’s

45–500+ 0–45 Variable Sugar and chloride

values falling

progressively

Early, acute

syphilitic meningitis

 ↑ Clear to turbid,

occasional clot

25–2000

mostly

lympho’s

45–400+ 15–75 Ist/midzone

curve

Often +ve serologic test

in CSF and blood

Late CNS syphilis ↑ Normal Normal or ↑ Normal or ↑ Normal Depending

on activity

Often +ve serologic test

in CSF

Aseptic meningeal

reaction (brain or

extradural abscess,

thrombosis, etc.)

Usually

normal

Clear or

turbid, often

xanthochromic

 ↑ Normal or ↑ Normal Variable CSF culture negative

Acute poliomyelitis Usually

normal

Usually clear

and colorless

 ↑ ↑ 45–100 Normal or

midzone

Viral encephalitis

(arthropod borne)

Normal or ↑ Normal 0–100,

mostly

Normal or

increased

45–100 Variable Proved by serologic

tests

Viral meningoencephalitis

Normal or ↑ Normal 0–2000

+ mostly

lympho’s

Normal or ↑ Normal Variable Proved by virus

isolation and serologic

tests

Postinfectious

encephalitis

Usually ↑ Normal Slightly ↑ Normal or

increased

Increased Variable

Traumatic (bloody)

tap

Normal Bloody Many fresh

RBCs

 ↑ Normal Normal Most blood in Ist tube,

least blood in last tube

Cerebral

hemorrhage:

ventricular,

subarachnoid

Slightly ↑ Bloody,

supernatant

yellow

Many RBC’s

crenated or

fresh

 ↑ Variable Normal Blood present in all

specimens equally

Subdural hematoma Usually ↑ Clear/yellow Normal Normal or ↑ Variable Normal

Brain tumor Usually ↑ Clear/xanthochromic

Normal or

increased

Usually ↑ Normal or

increased

Variable If papilledema is

present lumbar

puncture is

contraindicated

Spinal cord tumor

(Subarachnoid

block)

Normal or low Often xanthochromic

Normal

or ↑

Usually ↑ Normal or

increased

Variable Little fluid obtained

Multiple sclerosis Low Normal Normal or

increased

Normal or

increased

Normal Normal, Ist

or midzone

50% cases have

normal CSF

Uremia Usually Normal Normal or ↑ Normal or ↑ Normal

or ↑

Variable CSF NPN is high

Diabetic coma Low Normal Normal or ↑ Normal Increased Normal May have spasticity,