CSF ANALYSIS

• Historical background.• Anatomy and csf circulation. • Techniques of CSF examination. • CSF findings.

Historical background• James leonard corning- 1885Corning injected cocaine between the  spinous processes of the lower  lumbar vertebrae.

• Quincke,1891introduction of the lumbar puncture for diagnostic and therapeutic purposes.

Contd……• Quickenstedt,1916Manometric findings of spinal subarachnoidBlock.

• Dandy ,1918description of the circulation of cerebrospinal fluid in the brain, surgical treatment of hydrocephalus. 

CSF circulation- • colourless,clear fluid.

• CSF flows through the brain

through ventricles, and they lie

deep inside the brain. The fluid-

filled ventricles protect the brain;

like a cushion. Most of the CSF is

made in the choroid plexus, a

part of the brain.

Choroid plexus –villous invagination of the walls of lateral,3rd and 4th ventricles,lined by ciliated epithelium

3rd ventricle

4th ventricle

Prepontine cistern Cerebellopontine angle

Cisterna magna

Cerebellar hemispheresSpinal subarachnoid space

Absorbed in venous sinuses across the arachnoid villi in the dural lining of venous sinuses

Foramina of monroe

f.magendieF. lushka

Aqueduct of sylvius

CSF characteristics; • Volume of brain= 1400 ml

• Volume of CSF= 150ml

• CSF in ventricles =25 ml

• Volume of blood= 150 ml

• Total volume of cerebrospinal fluid (adult) = 125-150 ml

• Total volume of cerebrospinal fluid (infant) = 50 ml

Contd….• Turnover of entire volume of cerebrospinal fluid = 3 to 4

times per day

• Rate of production of CSF = 0.35 ml/min (500 ml/day)

• pH of cerebrospinal fluid = 7.33

• Specific gravity of cerebrospinal fluid = 1.007

• Color of normal CSF = clear and colorless

TECHNIQUESOF CSF EXAMINATION

• Lumbar puncture• Cisternal puncture • Ventricular puncture• Subcutaneous CSF reservoir

Lumbar puncture• Spinal cord and spinal column are of same

length up to 3 months of age

• Cord ends at L1-2 in 51-68%, T12-L1 in30%, L2-3 in 10% of adults

• Thecal sac ends at S2

Lumbar puncture • Knee chest position • sitting

Lumbar puncture• Sites• L3-4 - ADULTS

• L4-5 - CHILDREN

L5-S1 - INFANTS

• LP needle’s- 1) QUINCKE’S

2)Atraumatic needlesizes:1)18-20 Gauge - manometry

2)22 Gauge - diagnostic tap

3)14 Gauge tuohy needle / stameyureteric catheter for spinal drainage

Steps:• Cleaning and draping• Infiltration of anesthetic• Bevel parallel to longitudinal dural fibers

Trajectory- directed slightly rostrallytowards umbilicus

• Confirmation of needle patency• Connection to manometer -stop if opening

pressure is >240 mm H20• Quickensteadt test in suspected

subarachnoid block

Collection of CSF• 3 Vials for cell count, protein/glucose,

gram stain/culture

• 4 vials in suspected traumatic tap

• For cyto pathology 5-10 ml CSF should

be sent.

• CSF should be sent immediately

• CSF can be preserved at 4 degree Celsius

Indications• Suspicion of meningitis• Suspicion of SAH• Suspicion of central nervous system

diseases such as Multiple sclerosis,Acute disseminated encephalomyletis,Guillain Barr’e syndrome

• Theurapeutic relief of benign intracranial hypertension

Contraindications:• ABSOLUTE:unequal pressures between the

supratentorial and infratentorial compartments,usually inferred by charesteristics on the brain CT scan:

a) midline shift b)loss of suprachiasmatic and basilar cisterns c)posterior fossa mass d)loss of the superior cerebellar cisterns e)loss of quadrigeminal plate cistern• Infected skin over the needle entry site.• RELATIVE:increased ICP,coagulopathy,brain abscess

Indication of CT brain before LP

• Patient who are immunocompromised.• Patient with known CNS lesion.• Patient who have had a seizure within 1 week of

presentation.• Patient with abnormal level of consciousness• Patient with focal findings on neurological

examination.• Patient with papilledema seen on physical

examination with clincal suspicion of elevated ICP

Complication of LP• Tonsillar herniation- acute / chronic Infection

• Spinal headache

• Spinal epidural hematoma

• Spinal epidural CSF collection

Epidermoid tumor• Nerve root injury

• Ocular abnormalities - abducens palsyDural sinus thrombosis

Normal CSF findings• Gross appearance-clear and colourless• CSF opening pressure-50-175mmH2O• Specific gravity-1.006-1.009• Glucose-40-80mg/dl• Total protein-15-45mg/dl• Lactate-less than 35mg/dl• leukocytes-(WBCs)-0-5/mm3(adults and children) up to 30/mm3 in newborns

Contd….• Differential-60-80% lymphocytes; up to 30%

monocytes and macrophages ; other cells less than 2%.monocytes and macrophages are some what higher in newborns.

• GRAM STAIN-negative and culture sterile.• Red blood cell count-normally, there are no red

blood cells in CSF unless the needle passes through a blood vessel on route to the CSF.

Opening pressure• Position-lateral decibitus position• Patient should not strain can increase opening pressure

or hyperventilate which will lower opening pressure.• Normal-120-200mmHg neonates-90-120mmHg• >250mmHg are diagnostic of IC HTN.• When the elevated pressure is discovered ,CSF should

be removed slowly ,no additional CSF should be removed once the pressure reaches 50% of opening pressure.

Supernatant fluid color

• Normal CSF is crystal clear• However >200 WBCs/mm3 or 400 RBCs/mm3 will cause

CSF to appear turbid.• XANTHOCHROMIA-yellowish,orange or pink

discoloration of CSF –lysis of RBCs,>90% in SAH,hyperbilirubinemia,CSFprotein levels of >150mg/dl.

Color of supernatant CSF

causes

yellow

• Blood break down products.• Hyperbilirubinemia• CSF protein >150mg/dl,>100,000

RBCs/mm3Orange Blood break down products

High carotenoids intake

Pink Blood break down products

Green HyperbilirubinemiaPurulent CSF

Brown Meningeal melanomatosis

features Traumatic tap SAHRBC count and grossAnd gross appearance of bloodiness

decreases Little change

WBC/RBC Similar to peripheral

picture

leucocytosis

supernatant clear xanthochromic

Clotting of fluid Clots if RBC count >200,000/cumm

Does not clot

Protein conc. Rise 1mg/1000 RBC >1mg/1000RBC

Repeat LP at higher level clear Remains bloody

Opening pressure normal Usually elevated

test bacterial viral tubercular

Opening pressure

elevated Usually normal Variable/elevated

WBC count >1000/mm3 <100/mm3 Usually elevated

Cell differential Predominance of PMNs

Predominance of lymphocytes

Predominance of lymphocytes

protein Mild to marked elevated

Normal to elevated

marked elevated

CSF to serum glucose ratio

decreased Usually normal Low/normal

test fungal Partially treated meningitis

Brain abscess

Opening pressure

variable Normal/elevated

elevated

WBCs count variable increased incresed

Cell differential Mononuclear cells,but cryptococcus may have no cells

Mononuclear cells predominat

Predominantnly lymphocytes

protein elevated Mild/marked elevated

elevated

CSF to glucose ratio

low Normal/decresed

normal

•Thank you