Nerve water

Synonyms

Cerebrospinal fluid

Medical: Cerebrospinal fluid

definition

The nerve water (Cerebrospinal fluid), also known as liquor for short, is an endogenous fluid that is largely contained in the chambers (ventricles) of the brain by specialized vascular plexuses, the so-called Choroid plexus, is formed. The formation takes place via filtration of the blood. Humans have around 100-150 ml of liquor fluid (nerve water). Since the specialized cells of the choroid plexus produce around 500 ml of liquid per day, the entire volume of fluid must be exchanged between 3 and 4 times a day. This is done by taking back (Absorption) of the cerebrospinal fluid into the venous vascular system via protuberances in the spider's web (arachnoid). The protuberances are known as Pacchioni granulations or arachnoid villi. If this resumption did not exist, the intracranial pressure would rise steadily and turn into a head of water (Hydrocephalus) to lead. The normal CSF pressure is between 70 and 220 mmH2O, but it can fluctuate throughout the day as well as when breathing with pressure or when changing position.

Since the liquor / Nerve water is related to the tissue fluid of the brain, it is also similar in its composition. By having the brain and that Spinal cord Washed around, the liquor protects it Central nervous system against external influences such as vibrations. It also has a nutritional role for him Neurons attributed to. However, details are not yet known.

Cerebrospinal fluid

The liquor / Nerve water is located in two anatomically demarcated spaces that are, however, connected to each other: the outer and the inner CSF space.

1. The outer liquor space is located between the two parts of the soft Meninges, between the pia mater and the spider web skin (Arachnoid). This gap, in which the CSF flows, is also known as the subarachnoid space and is found around the brain as well as the Spinal cord.
2. The inner liquor space consists of a system of cavities in the brain, the so-called Ventricular system. The vascular plexuses in which the liquor is produced are also located in these ventricles. You have a transport and production function.

The system consists of 4 ventricles connected in series: 2 symmetrical lateral ventricles in the Cerebrum (Telencephalon), a 3rd ventricle in the Diencephalon (Diencephalon) and a 4th ventricle in the hindbrain (Rhombencephalon). The ventricles are connected to each other. Between the two side ventricles and the third ventricle there is a connection in the form of a foramen interventricularis each. The aqueduct leads from the 3rd to the 4th ventricle. The latter goes over into the central canal of the spinal cord.
Please also read our article on this Cerebral ventricle

The outer and inner liquor space are also connected to one another via a total of three openings: two Aperturae laterales as well as one Apertura medianathat lead from the ventricular system into the subarachnoid space.

When examining the nerve water obtained during the puncture, conclusions can be drawn about the causative agent of the disease. The causative agents of the diseases can bacterial or more viral Be origin. Sometimes the pathogens are too Mushrooms, it can also be with a Brain tumor Tumor cells can be detected in the nerve water. Based on the composition of the Electrolytes, of sugar (glucose) and proteins (Proteins) you can determine which therapy is most useful.

Using the example of meningitis (Meningitis) this system can be illustrated well. This is the case with bacterial meningitis Greatly increased protein is during the Sugar very low is and that Lactate also greatly increased is. In the case of viral meningitis, on the other hand, they are Proteins only slightly increased, whereas Sugar and lactate normal stay. Meningitis caused by the pathogen of the tuberculosis is triggered. Here is that too Greatly increased protein, the However, lactate is only slightly increased, during the Low sugar is.

Of course, not only these parameters are examined in the nerve water. The so-called liquor is usually still examined by microbiologists. During the examination, the pathogens are incubated from the nerve water, so that after a few days it is clear which specific pathogen is involved. These can be bacteria such as meningococci or pneumococci. These can then be treated with antibiotics. It is important to choose the right antibiotic, this is determined by a so-called antibiogram. For this antibiogram, culture media are inoculated with the bacteria and various antibiotics and incubated for a few days.

If the bacterium can grow despite the antibiotic, it is called resistance. If the bacterium cannot grow in places where there is also an antibiotic, this antibiotic can be used to treat this bacterium. When diagnosing viral pathogens, the antibodies IgM and IgG initially play an important role. These antibodies are produced by the body and allow conclusions to be drawn about whether it is an old or a new viral infection. The viral proteins, which are, so to speak, the calling card of the viruses, can be examined in the Western blot or by an immunofluorescence test. If the virus itself is to be broken down, genome sequencing can be carried out for this purpose.

Also read the article on the topic: Choroid plexus

composition

Usually the liquor / Nerve water clear and colorless, so that it resembles water in its appearance. It contains very few cells, around 0-3 or 4 per µl. At the Newborn this number can be about twice as high. Mainly found in the Nerve water Leukocytes, including especially the Lymphocytes, so immune cells. Other cells are also less common, such as Granulocytes, Monocytes or the den Spinal canal lining Ependymal cells. In healthy people, however, there are never red blood cells (Erythrocytes) to be found in it. If it does, it may be an indication of bleeding in the subarachnoid space.

In contrast to serum (60-80g / l), the liquor contains only an extremely small amount of proteins (see also protein), about 0.2-0.4g / l and a little more than half of the blood sugar content, about 40-80mg / dl.

Puncture / collection of nerve fluid

If a disease or a suspected disease of the Backmarks or des Brain exists, for example a Inflammation of the meninges (meningitis), the examination of the nerve water (Liquors) at. The removal of the CSF is carried out under strictly sterile conditions in order to avoid infection. To be the best possible Puncture site to find, the doctor first gropes for the Iliac crest and gropes from there to the Spine away. Does he now have the at this height whirl felt, he marks it and asks the patient to bend forward. It is important that the puncture site is below the end of the spinal cord to avoid injuries to the Nerve cord to avoid.

With children you have to make sure that the doctor punctured even deeper than in adults, since in children that Spinal cord ends lower than in an adult. Then the puncture is prepared sterile. First, the site of the puncture is disinfected over a large area and covered with the sterile perforated cloth. This is followed by the local anesthesia the puncture site. After an exposure time of about five minutes, the Spinal canal to be punctured. Damage to the spinal cord rarely occurs because the puncture site is chosen deeper than the end of the spinal cord. When the puncture is successful, the nerve water usually drips out slowly, for example, the nerve water flows in more quickly and with more pressure increased intracranial pressure.

After the puncture, it is important that the patient is on the patient for the first few hours after the procedure move to lie down. This is to avoid that the nerve water is only distributed in the spinal cord space and the brain is no longer surrounded by nerve water in this way. This sagging of the nerve water can lead to a so-called upper or lower entrapment of the brain lead and put the patient in a life-threatening condition. However, this complication occurs very rarely. Another complication can be infections caused by the puncture, this can be from local infections of the skin extend to infections that affect the entire body.

Increased intracranial pressure

A Increase in intracranial pressure can be congenital or acquired. The causes can also be different, either the outflow of the nerve water is disturbed or there is an increased production. Due to the excess of nerve water, there is enough space in the so-called Ventricles of the brain no longer and the brain mass is pushed to the edge. This can be so strong that it becomes too Circulatory disorders of Brain can come. When the nerve water is removed, this manifests itself in a strong gushing out of the nerve water.

However, this sudden pressure relief can also lead to problems, as the brain can now slide down into the spinal cord space, which is a life-threatening situation. For example, in children born with a drainage disorder, im CT Realize that the brain is not pressed to the side, but that these children are greatly enlarged Nereven water areas in the Gehrin (Ventricle) to have. This is with a so called Shunt, a kind of overflow valve, treatable. In some cases, children with one point Water head (Hydrocephalus) mental retardation on. These mental limitations can be mild to severe.

Diagnosis

To get the liquor / Nerve water In order to be able to examine it in a laboratory, it must be obtained from the spinal canal. To do this, a long needle is inserted into the spinal canal and the fluid can escape (Lumbar puncture).

The Lumbar puncture can be carried out on both the seated and the lying patient. The only thing that is important is the most efficient possible curvature of the lower back, as this causes the extensions of the Spine diverge further and thus the puncture through the ligamentous structures of the spine is facilitated. The puncture is made at the level of the space between the third and fourth or fourth and fifth lumbar vertebrae in order to avoid injuries to the spinal cord. Since the spinal cord ends roughly at the level of the first lumbar vertebra, there is little risk of a lesion. Should a CSF removal in the Lumbar region not be possible, as is seldom the case Tumor involvement the Spine can occur, a removal from the so-called Cisterna cerebello-medullaris possible, a space between the occiput and the first cervical vertebra.

With the usual lumbar puncture, the needle is pushed into the spinal canal until the nerve fluid emerges. This is collected in test tubes and examined. In order to avoid complications such as infections, strictly sterile conditions should be created and patients should subsequently keep bed rest. Make sure you drink enough fluids after the procedure a headache to avoid. Bleeding from the puncture is rare.

Many diseases of the central nervous system cannot be diagnosed by blood tests alone; the lumbar puncture is often the method of choice here. This can be used to detect viral or bacterial infections that cause inflammatory reactions. Bleeding of the subarachnoid space, i.e. bleeding from the brain / Cerebral hemorrhage The vessels supplying the skull base as well as tumorous changes in the central nervous system can be assessed. Fungal and parasite infections are less common.

After removal of the liquor / Nerve water This is examined in the laboratory for the following criteria: macroscopically for color changes and cloudiness, which often allow a first suspected diagnosis, microscopically for cell type and number, protein, sugar and mineral content, antibodies as well as bacteria and fungi.

Since diseases of the central nervous system (CNS) with a change in the CSF / Nerve water or its composition can often be used to confirm suspected diagnoses by means of CSF diagnostics. Inflammatory diseases of the CNS such as inflammation of the brain (Encephalitis), Meningitis (meningitis), Inflammation of the spinal cord (Myelitis) or autoimmune inflammatory diseases like the multiple sclerosis can be judged. When it comes to bacterial infections, primarily neutrophils, a subtype of white blood cellsto prove. In viral infections, however, there are more lymphocytes. Tumor cells in Nerve water direct the suspicion of a tumor infestation of the meninges (Meningeosis neoplastica), which in lymphoma, Leukemias or carcinoma can occur. Bleeding of the subarachnoid space, which originates from arteries supplying the brain, is caused by the occurrence of Erythrocytes (red blood cells) im Nerve water approved. However, it is important to watch out for artifacts, since small amounts of blood can also be caused by the puncture during the puncture. Also for the diagnosis of Lyme borrelioses and neurolues (last stage of syphilis) the CSF examination can be used.

An absolute contraindication for a lumbar puncture is increased intracranial pressure, as the removal of liquor can cause the brain to sag and become trapped. The respiratory center is compressed and there is a risk of respiratory arrest with an immediate threat to life. Therefore, a measurement of the intracranial pressure is essential before a cerebrospinal fluid is withdrawn.