Chemical Components of CSF ِAnalysis

BYDr KHALED SALEH ALGARIRI

IMS – MSU May 2016

CSF LACTATEIn neonates (10-40mg/dl) .

In adult or older children (10-22 mg/dl) Measurement of lactate concentrations in cerebrospinal fluid (CSF) may be useful as part of the investigation of inborn errors of metabolism in which lactic acidosis occurs.

This includes disorders of gluconeogenesis, pyruvate dehydrogenase complex, the Krebs cycle and the mitochondrial electron transport chain.

Levels greater than 35 mg/dl are frequently seen with bacterial meningitis (due to increased glycolysis by bacteria & inflammatory cells), whereas in viral meningitis, lactate levels remain lower than 25 mg/dl.

CSF LACTATE contCSF lactate levels remain elevated during initial treatment but fall

rapidly when treatment is successful, thus offering a sensitive method for evaluating the effectiveness of antibiotic therapy.

Measurement of lactate in CSF has also been advocated for investigating children with unexplained neurological disease

CSF GLUTAMINE

Normal range 8-18 mg/dL Glutamine is produced in the CNS by the brain cells from

ammonia and alpha-ketoglutarate. This process serves to remove the toxic metabolic waste product ammonia from the CNS.

Glutamine synthesis helps to protect the CNS from the toxic effects of increased ammonia.

Ammonia production is increase dramatically in patients with liver failure.

Accordingly, CSF glutamine production is increased in cases of hepatic encephalopathy

CSF ENZYMESLactate dehydrogenase

LDH – LD1, LD2, LD3, LD4, LD5 -Increase LD5 in metastatic brain tumor. -Increase all fractions in primary brain tumor such asMeningioma ( extra- exial)Glioblastoma (intra – exial) -Increase LD4,LD5 in bacterial meningitis.

CSF ENZYMESCK – BB: -Increase in: epileptic patient Brain tumor cerebral infarction

CSF ENZYMESCSF adenosine deaminase (ADA) elevations can occur in tuberculous meningitis.

Other Chemical Components of CSF CSF [Calcium], [Potassium] & [Phosphates] are lower than their

levels in the blood

CSF [Chloride] & [Magnesium] are higher than their levels in the blood

Abnormal CSF [Chloride] marked in acute bacterial meningitis slight in viral meningitis & brain tumors

What is the function of CSF? To supply nutrients to the nervous system To remove metabolic wastes The presence of a number of biologically active

principles (releasing factors, hormones, neurotransmitters, metabolites) within the CSF suggests that it may function as a transport system.

To produce a mechanical barrier to cushion the brain and spinal cord against trauma

How many times perday is CSF completely replaced?

What is the estimated total volume of CSF? 140 mL

3 to 4 times per day

What is the difference between CSF and blood in terms of protein concentration?CSF has reduced protein concentration

Compare Blood and CSF Glucose, Calcium and Potassium levels. CSF has lower glucose, calcium and potassium concentrations than in the plasma

What indicates a hemorhage in the brain?

What does protein content of >150 mg/dl indicate?That bilirubing (bound to albumin) has been brought from the plasma to the CSF.

Grossly bloody or yellow (xanthochromia) color

What does a protein content of greater than 500 mg/dl indicate?

What occurs to the CSF concentration of glucose during an acute bacterial infction?

Decreases

Usually a manifestation of a block in the spinal subarachnoid space by a tumore, meningeal cancer or other compressing lesion

In multiple sclerosis and other inflammatory disease what happens to gamma-globulin content in the CSF?It is increased in the CSF

What is a hydrodynamic disorder of the CSF leading to an excess of intracranial CSF?Hydrocephalus

What is characterized by an expansion of the ventrilces and frequently an increase in intracranial pressure?

Hydrocephalus

What are the three reasons behind hydroencephalus?

What is one possible cause behind oversecretion of CSF?

Papilloma or tumors of the choroid plexus

Over secretion of CSFImpaired reabsorption of CSFObstruction of CSF circulation

How many tubes of CSF should be collected for CSF examination?

Tube 1 – used for chemical and serologic test: centrifuge and use supernatant for chemistry analysis (glucose, protein, chloride)

Tube 2 – used for microbiology lab

Tube 3 – used for hematology (cell count) Cell counts done as soon as possible after the fluid is collected as cellular degradation occurs rapidly. If postponed, refrigerate for up to one hour.

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