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Evaluation of CSF
• Cerebrospinal fluid (CSF) is a clear fluid present in the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space.
• CSF is produced in the brain by modified ependymal cells in the choroid plexus (approx. 50-70%), and the remainder is formed around blood vessels and along ventricular walls.
Functions of CSF
• Protects, lubricates the brain• Provides nutrients, removes waste 90-150 ml adult 10-60 ml in newborn• Modulates pressure changes (Buoyancy) • Serves as a chemical buffer to maintain
constant ionic environment• Serves as a transport medium for nutrients
and metabolites, endocrine substances and even neurotransmitters
Circulation of CSFLateral ventricles
interventricular foramen of Monroe
third ventricle
mesencephalic aqueduct (aqueduct of Sylvius)
fourth ventricle
spinal cord central canal; also, out the lateral apertures to the subarachnoid
space to the venous system
Circulation of CSF
Normal CSF
• Thin, colourless, clear fluid• Pressure 90-180mm WATER (10-100 neonates)• 0-5 WBC’s /mm3 (neonates 0-30/ mm3 ) (Lymphocytes & monocytes)• Occasional ependymal or choroid plexus cells• Protein 15-45mg/dl• Glucose 50-80mg/dl• Chloride 113-130 mEq/L• Sterile
• Appearance• Normal - Crystal clear, colorless• Descriptive Terms – hazy, cloudy, turbid, milky, bloody, xanthrochromic • Often are quantitated – slight, moderate, marked, or grossly. • Clots indicate traumat tap• pellicle formation –cobweb • Milky – increased lipids• Oily – contaminated with x-ray – media
• Xanthrochromic – Yellowing discoloration of supernatent (may be pinkish, or orange).• Most commonly due to presence of ‘old’
blood.• Other causes include increased bilirubin,
carotene, proteins, melanoma
• Cerebral hemorrhage• Even distribution of blood in the numbered tubes• Clot formation possible• Xanthrochromic supernatent
• – RBCs must have been in CSF @ 2+ hours• - D-dimer, fibrin degradation product from hemorrhage site• Microscopic presence of erythrophages, or siderophages,
Hemosiderin granules
Traumatic collection vs cerebral hemorrhage
Lumbar puncture
• a lumbar puncture (or LP, and colloquially known as a spinal tap)
• is a diagnostic procedure that is performed in order to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological, and cytological analysis
indications
1. To obtain CSF sample for cytological,chemical,cellular and bacteriological examination
2. To aid in therapy by the administration of soinal anesthetics and occasionally antibiotics or antitumor agents or by reduction of CSF pressure
3. To inject radiopaque substance as in myelography, or a radioactive agent , as in radionuclide cisternography.
complications
1. Headache2. Brain herniation3. Diplopia4. Subarachnoid haemorrhage5. Spinal epidural hematoma
contraindications
1. Infection2. Pailloedema3. Bleeding diathesis4. Severe pulmonary disease
COMMON FORMS OF MENINGITISCONDITION PRESSURE LEUKOCYTE PROTIEN GLUCOSE COMMENTS
Aute bacterial
Elevated(100-300)
100-10,000Usually PMN’s
100-500 Reduced <40< 50% of s.glucose
Gram stain or culture
Partially treated
Normal/elevated
5-10,000Usually PMN’s/mononuclear cells
100-500 Normal/reduced
Gram stain or anitgen detectionby agglitination test
Viral meningitis
Normal or slightly elevated
Rarely >1000 cells.intiallly PMN then lymph
50-200 Normal or reduced <40
Viral cultures/PCR, CT/MRI
Uncommon formsCONDITION PRESSURE LEUKOCYTE PROTEIN GLUCOSE COMMENTS
TBM Usually elevated
10-500, all lymphocytes
100-300, higher due to block
<50 % CSF is turbid with cobweb coagulum/PCR
syphilis Usually elevated
5-500 , all lymphocytes
50-200 Usually normal
CSF serology
Amoebic elevated 1,000 – 10,000,PMN’s
50-500 normal Mobile amoeba in hanging drop CSF exam.
Fungal meningitisORGANISM WBC’s PROTIEN GLUCOSE SMEARS SEROLOGY CULTURES
blastomyces
15,000(PMN’s/lymph)
300 normal rare No good rare
candida 600-1900 (mixed)
elevated low 40% positive
No good useful
coccidioides
100-750(lymphocytes)
150-2000 21 – 62% rare Antibody positive in 95% cases
Positive in 60 %
cryptococcus
40 – 400(lymphocytes)
high low India ink positive (25-50%)
Antigen positive(90%)
Positive in 75%
histoplasma
0 – 300(mixed)
normal Low(<40) rare Antigen positive (61%)
Positive (27-65%)
Brain abscess and parameningeal focus
condition pressure leukocyte protein glucose comments
Brain abscess Elevated(100-300)
5-200(lymphocytes)
75-500 normal Sterile,unless ruptures
Subdural empyema
Elevated(100-300)
100-5000(PMN)
100-500 normal sterile
Cerebral epidural abscess
normal 100-500(lymphocytes)
100-500 normal sterile
Spinal epidural abscess
low with spinal block
10-100(lymphocytes)
50-400 normal sterile
Chemical(drugs,dye,dermoid cyst)
elevated 100-1000(PMN)
50-100 Normal or decreased
Epithelial cells with dermoid
noninfectiouscondition pressure leukocyte protein glucose others
sarcoidosis normal 0-100(mononuclear)
40-100 normal none
SLE elevated 0-500(PMN) 100 Normal or decreased
Culture sterile
Tumors/leukemia
Elevatedto very high
0-100 50-1000 Normal to decreased
Cytology positive
SAH Opening pressure high
Normal increased normal xanthochromia
Demyelinating disorder condition pressure leukocyte protein glucose others
Multiple sclerosis
normal < 50 (lymphocytes)
normal normal MRI
ADEM normal > 50 (lymphocytes)
normal normal