- Examination of the cerebral fluid (liquor)
- Brain water examination
- Spinal fluid examination
Definition
On the basis of the composition of the cerebrospinal fluid (liquor) one can draw conclusions about diseases such as inflammations or tumor diseases of the brain or meninges. The collected values are compared with the values of the blood count. CSF diagnostics is a valuable examination in neurology (neuropathy), especially in cases of meningitis (inflammation of the meninges), encephalitis (inflammation of the brain), multiple sclerosis (encephalomyelitis dissiminata) and tumor diseases. The cerebrospinal fluid (liquor) for CSF diagnostics is usually obtained by means of a lumbar puncture.
Standard values
Liquor diagnostics can be used to detect diseases of the central nervous system. For this purpose, the individual parameters of the patient sample are compared with the standard values that are considered normal. Inflammatory processes can be detected even if the cerebrospinal fluid (liquor cerebrospinalis) is examined alone.
Normally, the cerebrospinal fluid is next to colorless; in the case of infections, it can appear cloudy. The pH-value of the cerebrospinal fluid in a healthy person is between 7.3 and 7.4. For a more precise examination, the cerebrospinal fluid is checked for its cell count.
In a healthy person, there should be little to no red blood cells. This also applies to eosinophil granulocytes (inflammatory cells, subgroup of white blood cells). The number of white blood cells should not exceed 4/μl in adults.
With certain measuring methods, the concentrations of individual molecules are also determined. These include above all glucose (60-85 mg/dl), lactate (<20 mg/dl) and total protein (10-40 mg/dl). For total protein, individual classes of antibodies are differentiated.
The mass concentration of IgA is below 0.5 mg/dl in the normal range, for IgM 0.1 mg/dl and for IgG 4.0 mg/dl. In addition, one pays attention to the occurrence of so-called oligoclonal antibody bands, which can provide information on multiple sclerosis, for example.
- Spinous process
- Spinal cord spinal canal
- Lumbar spine
- Basin shovel
The cerebrospinal fluid (cerebrospinal fluid) in a purulent, bacterial inflammation of the meninges (meninges) is purulent because white blood cells, in this case the so-called segment-nuclear leukocytes, fight the bacteria and migrate (pus consists of leukocytes and dead bacteria).
In healthy cerebrospinal fluid, these cells are not found in cerebrospinal fluid diagnostics; in purulent meningitis, there are several thousand to several tens of thousands. An increase in the number of cells in the cerebrospinal fluid is called pleocytosis. It is also present in non-purulent meningitis and other diseases of the central nervous system (CNS), but not as pronounced as in bacterial meningitis.
In bacterial meningitis, the pathogens are directly detectable microscopically in the extracted cerebrospinal fluid (CSF diagnostics) in 50% of cases, in a bacterial culture (CSF smear on culture media) in about 70% of cases. In bacterial meningitis, the protein content in the cerebrospinal fluid (CSF) is greatly increased (> 120 mg/dl), which is a sign of a disturbance of the blood-brain barrier. This normally prevents blood components from crossing over into the cerebrospinal fluid and can no longer fulfil this function: Protein gets from the blood into the cerebrospinal fluid.
The sugar content (liquor glucose) in healthy cerebrospinal fluid is about two thirds of the blood sugar value (serum glucose). In purulent meningitis, it drops to less than one third (<30 mg/dl; the cerebrospinal fluid/serum glucose ratio is then less than 0.3), because both the bacteria and the bacteria-fighting cells consume glucose. On the other hand, the lactate level – as a consequence of sugar consumption – rises sharply (usually above 3.5 mmol/l). This can also be used as a follow-up: Falling levels indicate an improvement, rising lactate levels a worsening of the disease.
