Composition
Normally the CSF/spinal fluid is clear and colorless, so that it resembles water in appearance. It contains very few cells, about 0-3 or 4 per μl. In the newborn, this number can be about twice as high.
Mainly leukocytes are found in the cerebrospinal fluid, among them mainly lymphocytes, i.e. immune cells. Less frequently, other cells are also found, such as granulocytes, monocytes or the ependymal cells lining the spinal canal. In healthy people, however, red blood cells (erythrocytes) are never found in them. If there are, this may be an indication of bleeding in the subarachnoid space. In contrast to serum (60-80g/l), cerebrospinal fluid contains only a very small amount of proteins, about 0.2-0.4g/l and slightly more than half of the blood sugar content, about 40-80mg/dl.
Puncture/spinal fluid removal
If there is a disease or suspected disease of the spinal cord or brain, for example an inflammation of the meninges (meningitis), the examination of the cerebrospinal fluid (liquor) is recommended for diagnosis. The liquor is removed under strictly sterile conditions to prevent infection. In order to find the best possible puncture site, the physician first palpates the iliac crest and from there continues on to the spinal column.
Once he has palpated the vertebra at this height, 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. In children, it is important to ensure that the doctor punctures even deeper than in adults, as the spinal cord ends deeper in children than in adults.
Then the puncture is prepared sterilely. First the puncture site is disinfected over a large area and covered with the sterile perforated cloth. This is followed by local anesthesia of the puncture site.
After a reaction time of about five minutes, the spinal canal can then be punctured. This rarely causes damage to the spinal cord, since the puncture site is chosen deeper than the spinal cord ends. When the puncture is carried out, the spinal fluid usually drips out slowly, faster and with more pressure, the spinal fluid runs, for example in the case of increased intracranial pressure.
After the puncture, it is important that patients remain lying on their back for the first few hours after the procedure. This is to avoid that the cerebrospinal fluid is only distributed into the spinal cord space and the brain is no longer surrounded by cerebrospinal fluid in this way. This subsidence of the cerebrospinal fluid can lead to a so-called upper or lower incarceration of the brain and thus 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 range from local infections of the skin to infections that affect the entire body.
