Central nervous system fluid, placed in the meninges and in the central cavities of the brain. What is its role and what are the pathologies involved?

Cerebrospinal fluid, also known as cerebrospinal fluid, is therefore the fluid in which the central nervous system, brain and spinal cord bathe.

It is a clear and colorless biological liquid and its composition is partially constant. It is secreted and absorbed without stopping and is completely changed 3 to 4 times in 24 hours.

The cerebrospinal fluid circulates in two different compartments:

• The external system: the subarachnoid space which is a space external to the central nervous system located in the spine, and which surrounds the spinal cord;
• The internal system: intra encephalic compartment, made of ependymal cavities or ventricle.

The cerebrospinal fluid is renewed frequently and has a volume that varies between 60 and 150 ml depending on the person.

The cerebrospinal fluid has an essentially mechanical protective function, it absorbs and cushions movements or shocks against external traumas that could damage the brain. Cerebrospinal fluid keeps the central nervous system in a constant physical and chemical environment. It helps maintain the brain and the spinal cord.

CSF is also the liquid in which molecules and “toxic waste” dependent on the brain are removed. It ultimately fulfills a role of “immunological protection”.

The composition of cerebrospinal fluid is similar to that of the blood from which it originates, but with less protein, more vitamin C and a distinct ionic concentration.

Poor CSF circulation can lead to symptoms:

• tired ;
• pain;
• dizziness;
• headache.

The normally transparent fluid becomes cloudy when infected and bloody during bleeding.

In which pathologies to take it:

Hydrocephalus: If cerebrospinal fluid gradually builds up in the ventricles, it puts pressure on the cerebral hemispheres. A slowdown in walking, an imbalance backwards or even difficulty in retaining urine and mental slowness are some of the signs;

• Brain tumors: the existence of malignant cells associated with an increase in volume caused by the brain tumor which induces a decrease in CSF can lead to a tumor pathology;
• Bacterial or viral meningitis: it is a completely sterile liquid therefore the presence of inflammatory cells (white blood cells, lymphocytes) and germs in the CSF is suspect;
• Subarachnoid hemorrhage: discovery of blood and high pressure of cerebrospinal fluid;
• Multiple sclerosis: looking for signs of inflammation, abnormal production of antibodies;
• Biomarkers and Alzheimer’s disease: there are three biomarkers, specific proteins of the LCS, in the CSF which have a sensitivity and help to detect certain degenerative diseases.

The composition of the CSF is relatively constant and any significant variation can be the indication of a pathology so the analysis of the cerebrospinal fluid can give particular information.

The CSF sample is usually taken from the lower lumbar region (below the terminal cone). Lumbar puncture should be performed under the established conditions: sterile room, by an experienced doctor.

The liquid is recovered by puncturing the back between two vertebrae, successively crossed the dura and the arachnoid. The doctor stops at the subarachnoid space, which is filled with CSF.

It suffices to take while aspirating a little liquid to take the sample.

Contraindication of a lumbar puncture

The CSF at low pressure. Elevated pressure is intracranial hypertension which contraindicates lumbar puncture. Indeed, there is in this case a risk that a small area of ​​the brain engages in the posterior confluence and causes sudden death.

In which pathologies to take it:

Hydrocephalus: can be treated with a valve that diverts excess fluid;

• Brain tumors: the main treatment is surgery, with the addition of radiotherapy or chemotherapy used to destroy other cancer cells or if surgery is not possible. The mode of treatment depends on several factors: severity of the tumor, its type, its location, the overall condition of the patient;
• Bacterial or viral meningitis: it is based on antibiotic drugs, for bacterial meningitis, and viral meningitis generally heal without treatment, except for the severe forms, meningoencephalitis, linked to herpes which require taking antivirals;
• Subarachnoid hemorrhage: treatment in a specialized center for the overall management of cerebrovascular accidents;
• Multiple sclerosis: treatment is based mainly on corticosteroids in bolus for relapses, and on ß interferons in relapsing-remitting forms for disease-modifying treatment;
• Alzheimer’s disease: the symptomatic drugs that are used do not cure the disease but try to slow down cognitive decline and reduce some behavioral disorders.