OVERVIEW ON CSF

PREPARED

BY

Mai Ghazy AL- Sarraj

Lumbar puncture indications:

• Suspicion of meningitis

• Suspicion of subarachnoid haemorrhage (SAH)

• Suspicion of central nervous system (CNS) diseases such as Guillain-Barré syndrome

• Therapeutic relief of pseudotumor cerebri

Contraindications of LP

1. elevated ICP owing to a suspected mass lesion of the brain or spinal cord

2. symptoms and signs of pending cerebral herniation in a child with probable meningitis symptoms and signs include decerebrate or decorticate posture, a generalized tonic seizure, and abnormalities of pupil size and reaction, with absence of the oculocephalicresponse and fixed oculomotor deviation of the eyes. Pending herniation is also associated with respiratory abnormalities, including hyperventilation, Cheyne-Stokes respiration, ataxic breathing, apnea, and respiratory arrest,(

3. critical illness (on rare occasions)

4. skin infection at the site of the LP

5. thrombocytopenia.

Indications for performing brain CT scanning before lumbar puncture

• in patients with suspected meningitis include the following[8] :

immunocompromisedwith known CNS lesionshad a seizure within 1 week abnormal level of consciousnesspatients with focal findings on neurologic examinationpapilledema &suspicion of an elevated ICP• Cranial CT scanning should be obtained before lumbar puncture in

all patients with suspected SAH in order to diagnose obvious intracranial bleeding or any significant intracranial mass effect that might be present in awake and alert SAH patients with a normal neurologic examination

• Circulation:• Produced by modified

ependymal cells (approx. 50-70%), remainder is formedaround blood vessels, & alongventricular walls.

• Circulates from the lateralventricles to the Interventricularforamen, Third ventricle,Cerebral aqueduct, Fourthventricle, Median aperture andLateral apertures, Subarachnoidspace over brain and spinal cord.

• CSF is reabsorbed into venoussinus blood via arachnoidgranulations.

Amount of csf :

•The CSF is produced at a rate of 500 ml/day.

•The brain can contain only 135 to 150 ml

•The CSF turn over is about 3.7 times a day.

3c + one extra vials of CSF

Specimen volume:

4 tubes, 2-4 mL each

Tube 1: Microbiology.

Tube 2: Haematology, flow cytometry, cytology.

Tube 3: Chemistry.

Tube 4: Haematology, molecular and reference lab.

The reference range for cerebrospinal fluid analysis

• Opening pressure : 40-80 mm H2 O (with patient lying in lateral position)• Appearance and color : Clear, colorless

• Blood cell count and differential –• White blood cells: < 5 (all mononuclear) neonates up to 15• PMN always abnormal ……………………….. Neonate 1-2• Red blood cells: 0• Cancerous cells - None• Chloride - 110-125 mEq/L• Glucose : greater than two-thirds of blood glucose)• pH - 7.28-7.32• Total protein - 10-40 mg/dL..................... In neonates up to 120 & falls at age

of 3 month•

CSF findings in CNS infections

Pressure(40-80mm h2o)

Leukocytes(2-4mm3)

Protein (20-40mg/dl

Glucose (40-80mg/dl)

Bacterialmeningitis

increased 100-50000PMN

100-500 ( high) Low < 40

Viral meningitis N or increased Less than 1000Mononuclear

50-200( high) N or high

Viral encephalitis

N or increased Less than 1000PMN early, then mononuclear

50-200( high) N or high

T.B meningitis increased 10-500 Lymphocytes

100-500 (high) Low < 40

Brain abscess increased 10-200lymphocytes

100- 500 normal

What is the normal and abnormal value of CSF glucose and protein ?

• Glucose – Normal CSF serum glucose ratio 0.6

– < 0.4 is found in ABM +TB

• Protein – Normal range is 40-170 mg/dl in neonate

– Normal range is 15-45 mg/dl in children.

– Higher level in ABM +traumatic LP

• http://www.fpnotebook.com/neuro/lab/CrbrspnlFldExmntn.htm

• http://www.rch.org.au/clinicalguide/guideline_index/CSF_Interpretation/

• http://www.osceskills.com/e-learning/subjects/cerebrospinal-fluid-results-interpretation/

• http://emedicine.medscape.com/article/2093316-overview

Thank you