With purulent processes in the cerebrospinal fluid. How is CSF analysis done, and what diseases can it reveal? When analysis is indispensable

Diagnostic research includes the following procedures:

Clinical and biochemical analysis of blood.
Liquor analysis.
EEG (electroencephalography).
EMG (electromyography).

What is this liquid?

Liquor is a fluid that constantly circulates in the elements of the brain and spinal cord. Normally, it looks like a colorless transparent fluid substance that fills the ventricles of the brain, subarachnoid and subdural spaces.

Cerebrospinal fluid is produced in the ventricles of the GM by the choroid that covers these cavities. Liquor contains various chemicals:

vitamins;
organic and inorganic compounds;
hormones.

In addition, in the liquor there are substances that process the incoming blood with its decomposition into useful nutrients. Along with this, there is a production of a sufficient content of hormones that affect the endocrine, reproductive and other body systems.

Reference! The main function of the cerebrospinal fluid is shock absorption: thanks to it, conditions are created to mitigate the physical impact when a person makes basic movements, which protects the brain from critical damage during a strong blow.

How is the research done?

The procedure performed to collect CSF is called a lumbar puncture. For its implementation, the patient takes a supine or sitting position. If the subject is sitting, he should be straight, with his back bent so that the vertebrae are located in one vertical line.

In the case when the patient is lying, he turns to his side, bending his knees and pulling them to his chest. The injection site is chosen at the level of the spinal column, where there is no risk of damaging the spinal cord.

Lumbar puncture is a procedure that can only be performed by a qualified doctor! The doctor treats the back of the subject with alcohol and an iodine-containing solution, after which he feels the puncture site along the intervertebral spaces: in adults at the level of II and III of the lumbar vertebrae, and in children between IV and V.

The specialist injects an anesthetic there, after which they wait 2-3 minutes to ensure tissue anesthesia. Then, with a Beer needle with a mandrel, the doctor performs a puncture, moving between the spinous processes and passing through the ligaments.

A sign of a needle getting into the subarachnoid space is a feeling of failure. If you then remove the mandrel, if the procedure is performed correctly, liquid will be released.

A small amount is taken for research.

Normal values in a healthy person

In the absence of pathology, the cerebrospinal fluid has the following composition:

Density: 1003-1008.
Cellular elements (cytosis): up to 5 in 1 µl.
Glucose level: 2.8-3.9 mmol / l.
Content of salts of chlorine: 120-130 mmol/l.
Protein: 0.2-0.45 g/l.
Pressure: in a sitting position - 150-200 mm. water. Art., and lying down - 100-150 mm. water. Art.

Attention! Normal cerebrospinal fluid should be clear, colorless and free of any impurities.

Table of the ratio of the form of the disease and the color of the liquid

	serous, viral	tuberculous	Syphilitic	Purulent
Color	Transparent	Transparent, opalescent	Clear, rarely cloudy	Turbid
Cells in 1 µl	20-800	200-700	100-2000	1000-5000
Protein (g/l)	Up to 1.5	1-5	Moderately elevated	0,7-16
Glucose (mmol/l)	Not changed	Dramatically reduced	Not changed	Dramatically reduced
Chlorides (mmol/l)	Not changed	reduced	Not changed	Reduced or not changed
Pressure (mm water column)	Upgraded	Upgraded	Slight increase	Upgraded
fibrin film	In most cases there is no	Present in 40% of cases	Missing	Coarse or sediment

The composition of the fluid

Depending on the causative agent of infection, cerebrospinal fluid may have a different composition. Let's take a closer look at the cerebrospinal fluid of 2 forms of inflammation.

Serous

Liquor characteristics:

Color - colorless, transparent.
Cytosis: Lymphocytic pleocytosis is found. The level of cellular elements is from 20 to 800 in 1 µl.
Protein values: elevated, up to 1.5 g/l (protein-cell dissociation).
The level of glucose and chlorides is not changed.

Purulent

Characteristics of cerebrospinal fluid in pathology:

Color - different depending on the causative agent of meningitis. For example, with meningococcus, it will be cloudy, yellow, with pneumococcus - whitish and bluish in the case of blue-purulent sticks.
Cytosis: a huge number of cells (cell-protein dissociation), reaching 1000-5000 cell elements per 1 µl. Neutrophilic pleocytosis is characteristic.
Protein content: high, within 0.7-16.0 g/l.
The glucose level is reduced, about 0.84 mmol / l.
The amount of chlorides is reduced or not changed.
The presence of a fibrin film in the cerebrospinal fluid or sediment.

Deciphering indicators

Based on the values of the cerebrospinal fluid data, specialists clarify the diagnosis and, in accordance with this, can prescribe adequate therapy.

Number of cells and cytosis

The cells in the cerebrospinal fluid are counted, followed by the determination of their predominant type. An increased content (pleocytosis) indicates the presence of an inflammatory process. More pronounced pleocytosis occurs with bacterial meningitis, in particular tuberculous inflammation of the meninges.

In other diseases (epilepsy, hydrocephalus, degenerative changes, arachnoiditis), cytosis is normal. Specialists count cellular elements, which are represented in most cases by lymphocytes or neutrophils.

Having studied the cytogram, the doctor can draw a conclusion about the nature of the pathology. So, lymphocytic pleocytosis speaks of serous meningitis or tuberculous meningitis with a chronic course. Neutrophilic leukocytosis - observed with acute infection (bacterial meningitis).

Important! During the analysis of cerebrospinal fluid, it is necessary to evaluate dissociation - the ratio of cellular elements with protein content. Cellular-protein dissociation is characteristic of meningitis, and protein-cellular dissociation is characteristic of serous inflammation of the meninges, as well as congestion in the cerebrospinal fluid (neoplasm, arachnoiditis).

Protein

Glucose

Glucose values should be 2.8-3.9 mmol/l. However, even in healthy people there may be slight fluctuations in the content of the substance. For a correct assessment of glucose in the cerebrospinal fluid, it is desirable to determine it in the blood: in the absence of pathology, it will exceed 2 times the value in the cerebrospinal fluid.

An elevated level is noted in diabetes mellitus, cerebrovascular accident, acute encephalitis. Reduced glucose levels occur with meningitis, neoplasms, subarachnoid hemorrhage.

Enzymes

Liquor is characterized by low activity of the enzymes contained in it. Changes in the activity of enzymes in the cerebrospinal fluid in various diseases are mostly non-specific. With tuberculous and purulent meningitis, the content of ALT and AST increases, LDH - bacterial inflammation of the meninges, and an increase in total cholinesterase - about the acute course of meningitis.

chlorides

Normally, the content of chlorine salts in the CSF is 120-130 mmol / l. A decrease in their level may indicate meningitis of various etiologies and encephalitis. An increase is noted in diseases of the heart, kidneys, dystrophic processes and formations in the brain.

Conclusion

The procedure for sampling cerebrospinal fluid must be carried out by a qualified experienced specialist, and the patient must follow all his instructions exactly. The study of cerebrospinal fluid allows the doctor to clarify the diagnosis and, based on these data, choose the right treatment.

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Meningitis is a dangerous disease of the brain, leading to disability and, in the absence of medical assistance, to death. Since the cerebrospinal fluid changes its properties during meningitis, the doctor, after examining him, can make an accurate diagnosis and immediately prescribe the necessary treatment. The cerebrospinal fluid is taken using a lumbar puncture (puncture). This procedure does not need to be feared, because it helps to choose the most effective method of treatment.

The cerebrospinal fluid controls the functionality of the nervous system. To get it, the doctor makes the patient a lumbar puncture. Liquor functions:

protect the brain from damage and exposure to mechanical factors;
maintain optimal pressure inside the skull;
promote metabolic processes between the brain and body fluids;
evacuate metabolic products;
keep the parts of the brain working.

The total volume of spinal fluid ranges from 140 to 270 cc. cm. It is formed by secretion by cells located in the vascular connections of the ventricles of the brain. Approximately 700 cubic meters are produced every day. see liquor.

Normal performance

Normally, cerebrospinal fluid has the following indicators:

density - from 1.005 to 1.009;
pressure should be in the range of 100-200 millimeters of water column;
there should be no coloration;
cytosis (per 1 microliter): ventricular fluid - up to 1, cisternal fluid - up to 1, lumbar fluid - within 2-3);
alkaline index - from 7.31 to 7.33;
total protein - from 0.16 to 0.33 grams per liter;
glucose index - from 2.8 to 3.9 mmol per liter;
chlorine (ions) - 120-128 millimoles.

Meningitis is an absolute indication for lumbar puncture. This procedure is prohibited if there are:

pronounced swelling of the brain tissue (the procedure can bring great harm);
a sharp jump in the pressure of the cerebrospinal fluid;
the presence of a large formation inside the brain;
dropsy.

Carrying out the puncture procedure for hydrocephalus and in the event of a pressure surge inside the skull can lead to a condition where a section of brain tissue extends into the opening of the occiput. At the same time, the work of the most important centers of human life support is disrupted.

During the puncture, the person is lying on his side, tilts his head to his chest and brings his legs bent at the knee joint to the stomach. This position provides optimal accessibility at the puncture site. It is located between the 3rd and 4th vertebrae in the lower back. There is no longer a spinal cord in this place.

Alcohol is applied to the puncture site, and an anesthetic is injected under the skin. The skin is pierced with a special needle with a tip. If it is entered correctly, then liquor begins to stand out through the needle.

Features of the analysis

Cerebrospinal fluid with meningitis is examined according to certain rules. Its first drops do not fall into the test tube and are carefully removed, because they have an admixture of blood. The liquid must be in a sterile and chemically clean test tube. It is collected in two vessels: one is sent for chemical and general clinical analysis, and the other for bacteriological.

All CSF samples are carefully protected from overheating and cooling. To determine the bacterial bodies, they are additionally heated.

Liquid analysis is carried out in several stages:

evaluation of color, volume, measurement of relative density;
cell count in the sample (in terms of 1 ml);
microscopic examination of the sample;
cytological examination of the stained sample;
biochemical analysis;
microscopy.

Deviations from normal indicators - video

In the presence of brain diseases, cerebrospinal fluid changes its characteristics:

If pathogenic microorganisms are present in it, then it turns greenish-gray. A large number of leukocytes are found in the liquid.
The red color of the cerebrospinal fluid indicates the presence of erythrocytes in it. It happens with an intense inflammatory lesion or after an injury.
With the development of inflammatory processes in the body, the cerebrospinal fluid becomes yellow and even brown, and hemoglobin decomposition products are found in it. This condition is called xanthochromia.

False coloration of the liquor is also possible. It happens with long-term use of certain medications.
The green color of the cerebrospinal fluid occurs with purulent inflammation of the lining of the brain.
The breakthrough of the cyst stains it in a dark shade.
With cytosis of protein elements, the cerebrospinal fluid becomes opalescent.
The disease process in the membranes of the brain increases the density of the spinal fluid to 1.015.
An increased amount of fibrinogen promotes the growth of fibrosis clots and pellicle. Usually such phenomena occur during the development of the tuberculosis process.

Sometimes enzymes are found in the cerebrospinal fluid. Normally, it should contain few enzymes. An increase in the content of these substances may indicate a violation of brain activity.

In meningitis, counting the number of microbial cells is of particular importance.. This number is essential for determining an accurate diagnosis and choosing a treatment method. The following calculation methods are used:

determination of the number of cells that are stained according to the method of Romanovsky Giemz or Noht);
calculation of CSF elements using the Fuchs and Rosenthal chambers. In its absence, a Goryaev camera is used.

An increase in cells in the CSF during meningitis is called pleocytosis. Often it is diagnosed during inflammatory diseases. This phenomenon is most pronounced in the tuberculous form of meningitis.

Staining with Samson's solution makes it possible to accurately differentiate microbial and other cells. With meningitis, the number of lymphocytes, neutrophils, monocytes, eosinophils, and basophils increases. The doctor is interested in the number of all these elements.

Slow outflow of cerebrospinal fluid, the impossibility of obtaining it, pronounced coloration, a discrepancy between the serious condition of the patient and the composition of the fluid, pronounced coagulation of the cerebrospinal fluid indicates that the patient develops blocked varieties of meningitis.

The presence of atypical cells in the fluid, while maintaining its transparency and the absence of an increased protein content, does not confirm the diagnosis of meningitis. The patient is referred for additional studies, since this symptom may indicate the progression of the malignant process of the brain.

Liquor in this case is heterogeneous. A feature of the disease process is that the number of pathologically altered cells and microorganisms is rapidly growing in the cerebrospinal fluid. If the patient is suspected of developing purulent meningitis, then his general study should be carried out no later than 60 minutes after the lumbar puncture.

The fluid in the spinal canal in purulent meningitis is usually opaque, green or milky in color. Laboratory studies confirm the growth of neutrophils, the spread of indicators of all formed elements.

If the number of neutrophils in the spinal fluid is significantly reduced, this indicates that the outcome of the disease is favorable. CSF analysis for meningitis helps to determine the severity of the pathological process.

In the presence of purulent formations, the amount of protein increases, but with timely sanitation, it begins to decrease. The combination of pleocytosis and elevated protein indicates a poor prognosis for meningitis.

With a purulent variety of the disease, there is a decrease in glucose in the cerebrospinal fluid. If its amount increases, then this indicates a regression of the disease.

Laboratory indicators of tests for microorganisms in the tuberculous type of meningitis do not show positive results. A more thorough study of the cerebrospinal fluid helps to detect the presence of a pathogen in it.

Precipitation can be seen no earlier than 12 hours after analysis. The sediment looks like a fibrin mesh in the form of cobwebs or flakes. It can detect a large number of Mycobacterium tuberculosis.

In the tuberculous process, the cerebrospinal fluid remains clear, without noticeable color. Cytosis is in a fairly wide range and differs depending on the stage of meningitis. In the absence of etiotropic treatment, the number of cells always increases. Repeated sampling of CSF after the start of therapy notes a decrease in the number of cells.

A characteristic feature of the development of pathology is the presence of lymphocytes in the cerebrospinal fluid. If the level of monocytes and macrophages in it increases, this is a bad sign. In the cerebrospinal fluid, neutrophils and giant lymphocytes can be found in large numbers. Protein in this pathology usually increases, its rate can reach 3 grams per liter.

The glucose index in the cerebrospinal fluid in tuberculous meningitis drops sharply to 0.8 mmol. Sometimes the level of chlorides also decreases. A favorable indicator is an increase in the level of these indicators of cerebrospinal fluid.

A bacterial examination of the cerebrospinal fluid is carried out without fail to determine the type of pathogen. If the analysis was carried out on the first day after hospitalization, then in almost all cases pathological microorganisms are detected. On the 3rd day of the development of the disease, the number of microbes is significantly reduced.

Changes in cerebrospinal fluid go through several stages:

increased intracranial pressure;
development of neutrophilic type of cytosis;
the appearance of changes indicating the development of a purulent variety of meningitis.

If meningitis is not treated or goes wrong, then bacteria are found in the patient's cerebrospinal fluid. The amount of protein, neutrophils is growing. The more protein, the more pronounced the disease.

With pneumococcal form of meningitis, the fluid is cloudy, purulent, sometimes turns green. The number of neutrophils is moderate. Proteins can be up to 10 grams per liter and even more.

In serous meningitis, the cerebrospinal fluid is usually clear with a small number of lymphocytes. At the initial stage of the disease, there is some accumulation of neutrophils. it indicates a complicated course of the disease and usually indicates an unfavorable prognosis of meningitis.

Most often, protein indicators fluctuate within the normal range. Among some patients, the amount of this substance in the cerebrospinal fluid is slightly reduced, which is due to an increase in the production of cerebrospinal fluid. Pleocytosis is increased only in the case of meningitis caused by the Coxsackie type virus. With herpes, on the contrary, it is almost absent.

In the recovery stage, the patient has lymphocytosis. In mild cases, it is noted already on the third day of illness. With serous meningitis caused by the mumps virus, the cerebrospinal fluid is usually clear, without color. It detects the presence of lymphocytes, and the level of chloride ions and glucose increases slightly.

An examination of the spinal fluid for meningitis is mandatory: this is the only way to determine the presence of inflammation of the meninges in a patient and choose the most appropriate therapy. Do not be afraid of damage to the spinal cord, since it is not at all at the puncture site. After receiving the biological material, the laboratory assistant immediately conducts its study. This must be done as quickly as possible, because some forms of meningitis progress quickly, and every second is precious for the patient's recovery.

CSF (cerebrospinal fluid or CSF) is a constantly circulating and physiologically renewable fluid in the space of the spinal cord and brain. Its main goal is to protect the brain and spinal cord from injury due to mechanical impact, as well as to stabilize intracranial pressure and maintain fluid and electrolyte homeostasis.

The study of cerebrospinal fluid is usually required for suspected severe infectious diseases (most often with meningitis) and neurological pathologies (with multiple sclerosis, neurosyphilis). The procedure for taking cerebrospinal fluid for analysis is the same in children and in adult patients.

1 When and why is CSF analysis done?

A spinal analysis is considered a serious procedure, and without significant evidence (just like that, without suspicion of certain diseases), it is not performed. Indications for CSF sampling can be divided into two types: indications in the form of symptoms and indications in the form of diseases that need to be confirmed (or vice versa excluded).

Indications in the form of diseases (if the doctor suspects their presence):

Malignant neoplasms of any form and localization (usually this is how spinal tumors are looked for).
Traumatic brain injuries (in order to determine their complications).
Heart attack or stroke of the brain and / or spinal cord. Also, the procedure is carried out to search for the causes of such diseases.
Inflammatory diseases in the membranes of the brain that occur in isolation or against the background of infectious pathologies (with viral meningitis). With meningitis, the CSF sampling procedure is mandatory, even if the type of meningitis is known exactly.
Hernias of intervertebral disks.
Hematomas (hemorrhages, accumulations of blood) of the brain.
Epilepsy.

Indications in the form of symptoms:

persistent or episodic headaches, regardless of their severity;
dizziness, frequent nausea, vomiting;
loss of consciousness (syncope);
aphasia, dysphagia;
violations of the regulation of the work of internal organs;
visual artifacts, scotomas, blind spots, bouts of temporary loss of vision (including monocular);
gait disorders, motor skills (including micromotor skills);
sensory disturbances, paralysis, paresis;
suspicion of liquorrhea (the outflow of cerebrospinal fluid from the cranium, usually occurs against the background of injuries of the frontal segment).

Since these are common symptoms that occur with a large number of different diseases, the analysis of cerebrospinal fluid with them is not done immediately. First, doctors use other diagnostic methods, and only if necessary do the CSF sampling.

2 How is cerebrospinal fluid collected?

All patients are interested in the question: how do they prepare for the procedure and how is the cerebrospinal fluid taken for analysis.

First you need to purchase an analysis kit. It is sold at any pharmacy, but is sometimes included in the cost of the procedure.

Next, the patient is placed on the couch, and the sampling is carried out by the method of lumbar puncture. A special needle is used to make a puncture to gain access to the CSF circulation channel. It is done in the lumbar region, as the puncture here minimizes the risks of serious side effects.

A puncture can be performed not only for diagnostic purposes, but also for the purpose of treatment. Most often, with the help of a puncture, broad-spectrum antimicrobials are introduced into the subarachnoid space, with infectious lesions of the central nervous system.

The procedure is performed in a lying or sitting position. Most often, the puncture is carried out between 3-4 or 2-3 lumbar vertebrae.

2.1 Does it hurt?

Lumbar puncture is always performed with local anesthesia (usually a 1-2% novocaine solution is used). Novocaine is injected in layers along the puncture, the standard dose is 5-10 ml of Novocaine.

Most often, patients experience mild discomfort during the procedure, which can be easily ignored. But after the end of the CSF collection, pain may develop, which is a common complication.

The pain develops due to a decrease in intracranial pressure. It does not require treatment and resolves on its own within a week. Pain at the puncture site itself, if it occurs, is relatively weak, and usually disappears within 1-2 days.

2.2 Where is it made and how much does it cost?

The collection and subsequent analysis of cerebrospinal fluid is carried out in hospitals and large private clinics. The cost of CSF sampling (that is, the procedure itself, without further research) averages 1000-1500 rubles.

The further cost of diagnostics depends on how exactly the cerebrospinal fluid will be examined. Prices are like this:

A general clinical study of CSF has an average cost of 550 rubles.
General (laboratory) analysis will cost 800 rubles.
Diagnosis of multiple sclerosis (analysis for oligoclonal antibodies) will cost 10,000-12,000 rubles.
Bacteriological examination will cost 250-300 rubles.
Microscopic and biochemical (often called simply chemical) examination will cost 300-700 rubles.

2.3 How does it feel after taking CSF?

Immediately after the procedure, the patient's skin is disinfected at the puncture site and a patch is applied. The medical staff turns the patient on his stomach. In this position, you will have to lie for about 2 hours.

Usually, there is no pain in the lower back or pain in the head after CSF collection, but this is possible and is not a problem or abnormality. Already on the second day, the patient does not experience any discomfort when walking, and can almost fully return to full-fledged physical activity (except for weight lifting, sudden movements).

Severe consequences after the collection of CSF are rarely observed, especially in adult patients (due to the physiological characteristics of the structure of the spinal cord). You can minimize the risks of complications if you make a fence in specialized hospitals (which do such procedures daily).

3 CSF analysis rate

Normal indicators of CSF analysis are the same for men and women and practically do not depend on age (if we are talking about adult patients). Do not be surprised if some of your individual parameters do not fit into the norm, but the doctor considers you healthy. The fact is that the apparatus for interpreting analysis data often slightly overestimates individual indicators.

CSF analysis standards:

Parameter	Unit of measurement (quantity)	Normal
Color and transparency	analyzed visually (examined by a specialist)	should be completely transparent like water
CSF Density	grams per liter (g/l)	1003—1008
Pressure	millimeters of water column (mm water column)	in the supine position from 155 to 205, in the sitting position from 310 to 405
Medium reaction pH	pH	7.38-7.87
cytosis	microliters (µl)	1-10
CSF protein concentration	grams per liter (g/l)	0.12-0.34
CSF glucose concentration	millimoles per liter (mmol/l)	2.77-3.85
The concentration of chloride ions Cl- in CSF	millimoles per liter (mmol/l)	118-133

A few explanations about the table:

Differences between the indicators in the prone and sitting positions are not a mistake. The fact is that depending on the position of the body, the current of the cerebrospinal fluid changes, and therefore the parameters differ.
The indicator of the reaction of the medium implies the amount of hydrogen ions in it, which affect the predominance of acid or alkali in the liquid.
Cytosis refers to the number of cells in a fluid.
The amount of glucose in the cerebrospinal fluid depends on the age, diet, and daily routine of the patient.

Do not try to interpret the data obtained after the analysis of the CSF on your own (the numbers above are just for reference). Deciphering and interpretation should be done by a doctor.

4 Indicators for violations

Specialists who analyze cerebrospinal fluid take into account the color and density of the liquid, the concentration of proteins, chloride, glucose and cells. Any deviations from the norm are first rechecked (because the analysis is carried out by special equipment, which can fail)

The interpretation and decoding of the data obtained takes several days, although there are also express examinations (for meningitis, inflammation, trauma). Express decryption is carried out within a few hours.

Alone changes in the composition of the cerebrospinal fluid is not enough to make a diagnosis: the symptoms must also be taken into account. There are times when the composition is normal, but based on the symptoms, doctors still make a diagnosis. The opposite case is also possible - there are no symptoms at all, but according to the analysis there are clearly deviations (it happens in the initial stages of the disease).

4.1 Color and density

The color of the liquor should be clear, like ordinary water.(It is with distilled water that liquor is compared by experts).

CSF color changes and possible causes:

yellow-brown or green / gray: most likely a tumor in the brain, or a cyst; sometimes this indicates hepatitis or an excessive amount of penicillin administered (the latter is relevant only for newborns);
red: usually indicates a mechanical injury to the spinal cord or brain, concussion, hematoma / hemorrhage;
brown or dark cherry: usually indicates an accumulation of blood in the area of injury.

A low density of CSF most often indicates the presence of hydrocephalus, and at a high density, trauma or inflammatory diseases of the meninges are diagnosed.

4.2 Cell concentration

The increase in the number of cells is one of the most important parameters in the analysis of CSF. He can talk about the presence of various diseases, not only fatal ones.

Possible reasons:

active allergic reactions (sometimes an increase in the number of cells is a sign of the imminent appearance of an allergy);
meningitis of any etiology;
the presence of malignant neoplasms with metastasis to the membranes of the brain;
consequences of a heart attack or stroke of the brain.

Under allergic reactions usually mean systemic reactions (urticaria, collapse, anaphylactoid reactions).

4.3 Protein concentration

An excess of protein in the cerebrospinal fluid can indicate several diseases, most often of an infectious/inflammatory nature.

Possible reasons:

polio;
tumor neoplasms;
consequences of surgical intervention in the brain;
syphilitic paralysis;
traumatic or non-traumatic cerebral hemorrhage;
meningitis of viral or bacterial etiology.

Usually, with an increased concentration of protein, meningitis or polio is diagnosed (usually in children).

4.4 Chloride concentration

A reduced amount of chloride (Cl- ions) most often indicates the presence of a malignant neoplasm or meningitis of any etiology.

An increased amount of chloride indicates a malfunction of the kidneys (renal failure), less often about heart failure. Sometimes this may indicate the beginning of the development of malignant or benign neoplasms in the central nervous system.

4.5 Liquor is normal and with meningitis (video)

4.6 Glucose concentration

An increased amount of glucose (sugar) in the cerebrospinal fluid does not always indicate a problem: diurnal glucose fluctuations are often to blame. In other cases, an increase in glucose in the CSF is a sign of the development of diabetes mellitus, malignant neoplasms, encephalitis, or tetanus (if it is in the incubation period).

A low glucose level is also dangerous, and may indicate the presence of meningitis of a viral or infectious etiology, as well as the development of a neoplasm (not necessarily malignant) in the pia mater.

Neurosurgeons, neurologists and infectious disease specialists often have to perform a lombal puncture, that is, the collection of cerebrospinal fluid (CSF) from a patient. The procedure is a very effective way to diagnose various diseases of the central nervous system (CNS).

In clinics, CSF components are determined, microscopy is performed, and CSF is taken for microorganisms.

There are additional research measures, for example, measurement of CSF pressure, latex agglutination, checking the color of the supernatant. A thorough understanding of each of the tests allows specialists to use them as the most effective methods for diagnosing diseases.

Why analyze cerebrospinal fluid

Liquor (CSF, cerebrospinal fluid) is a natural substance required for the normal functioning of the central nervous system. Its analysis is the most important among all varieties of laboratory studies.

The analysis is carried out in several stages:

Preparatory- includes preparation of the patient, taking and sending the analysis to the laboratory.
Analytical- this is the procedure for studying the liquid.
post-analytical- is the decoding of the received data.

Only experienced specialists are able to competently perform all of the above actions, the quality of the analysis obtained depends on this.

Cerebrospinal fluid is produced in special plexuses from blood vessels in the brain. In adults, it circulates in the subarachnoid space and in the ventricles of the brain, from 120 to 150 ml of fluid, the average value in the lumbar canal is 60 mg.

The process of its formation is endless, the production rate is from 0.3 to 0.8 ml per minute, this indicator directly depends on intracranial pressure. During the day, an ordinary person produces from 400 to 1000 ml of fluid.

Only on the indications of a lumbar puncture can a diagnosis be made, namely:

excessive protein content in the CSF;
low glucose level;
determination of the total number of white blood cells.

Upon receipt of these indicators and an increased level of leukocytes in the blood, a diagnosis of "serous meningitis" is made, if there is an increase in the number of neutrophilic leukocytes, then the diagnosis changes to "purulent meningitis". These data are very important, since the treatment of the disease as a whole depends on them.

What is analysis

The fluid is obtained by taking a puncture from the spinal cord, also called lombal, according to a certain method, namely: inserting a very thin needle into the space where CSF circulates and taking it.

The first drops of fluid are removed (considered "travel" blood), but after that at least 2 tubes are collected. In the usual (chemical) one is collected for general and chemical research, the second one is sterile - for examination for the presence of bacteria.

When referring a patient for CSF analysis, the doctor must indicate not only the name of the patient, but also his clinical diagnosis and the purpose of the examination.

Analyzes delivered to the laboratory must be completely protected from overheating or cooling, and some samples are heated in special water baths, from 2 to 4 minutes.

Research stages

This liquid is examined immediately after its collection. Research in the laboratory is divided into 4 important stages.

Macroscopic examination

The process has several important indicators that are necessary to determine an accurate diagnosis.

Color

In its normal state, this liquid is absolutely colorless, it cannot be distinguished from water. With pathologies of the central nervous system, some changes in the color of the cerebrospinal fluid are possible. To accurately determine the color, the substance is compared in detail with purified water.

A slightly red tint may mean that impurities of unchanged blood have entered the liquid - erythrocytarchia. Or is it an accidental ingestion of a couple of drops of blood during the analysis.

Transparency

In a healthy person, CSF is clear and looks like water. A cloudy substance can mean that pathological processes are taking place in the body.

In the case when, after the centrifugation process, the liquid in the test tube becomes transparent, this means that the turbid consistency is due to some of the elements that make up the composition. If it remains cloudy - microorganisms.

A slight opalescence of the fluid may be due to an increased content of some dispersed proteins, such as fibrinogen.

fibrinous film

In a healthy state, it contains almost no fibrinogen. At its high concentration in a test tube, a thin mesh, a bag or a clot, similar to jelly, is formed.

The outer layer of the protein folds, resulting in a sac with liquid. Liquor, which contains a lot of protein, immediately after release begins to curl up in the form of a jelly-like clot.

If the cerebrospinal fluid contains red blood cells, the above-described film is not formed.

microscopic examination

Finding the total number of cells in the cerebrospinal fluid should be carried out immediately after taking the analysis, since its cells are characterized by rapid destruction.

Under normal conditions, cerebrospinal fluid is not rich in cellular elements. In 1 ml, you can find 0-3-6 lymphocytes, because of this they are counted in special high-capacity chambers - Fuchs-Rosenthal.

Under magnification in the counting chamber, the number of white blood cells in the fluid is calculated after all the red blood cells have been destroyed. Samson's reagent is used in the process.

How is it determined:

First of all, place CSF in vitro.
Reagent is filled into the melanger to the mark of 1 Samson.
Further, up to the mark of 11, add liquor and solution acetic acid, showing an admixture of erythrocytes, add fuchsin, which gives the leukocytes, more precisely, their nuclei, a red-violet color. After, carbolic acid is added for conservation.
Reagent and the cerebrospinal fluid is mixed, for this the melangeur must be rolled between the palms and left for half an hour for staining.
The first drop is immediately sent to filtering paper, mix the Fuchs-Rosenthal carem, consisting of 16 large squares, each of which is divided into 16 more, thereby forming 256 squares.
The last step is to count the total number leukocytes in all squares, the resulting number is divided by 3.2 - the volume of the chamber. The result obtained is equal to the number of leukocytes in 1 µl of CSF.

Normal performance:

lumbar - from 7 to 10 in the chamber;
cisternal - from 0 to 2;
ventricular - from 1 to 3.

Enhanced cytosis - pleocytosis, is an indicator of active inflammatory processes that affect the membranes of the brain, that is, meningitis, organic lesions of the gray matter (tumors, abscesses), arachnoiditis, injuries and even hemorrhages.

In children, the normal level of cytosis is higher than in adults.

Detailed steps for cytogram reading:

Liquid centrifuge for 10 minutes, the post-sedimentary is drained.
Sediment clean up onto a glass slide, rocking it slightly so that it is evenly distributed on the surface.
After smear dried warm throughout the day.
For 5 minutes immerse in methyl alcohol or 15 in ethyl.
take azure-eosin solution, previously diluted 5 times and stain the smear.
Apply immersion microscopy oil.

In a healthy person, only lymphocytes are present in the CSF.

If there are some pathologies, you can find all types of leukocytes, macrophages, polyblasts, cells of newly formed tumors. Macrophages are formed after blood loss in the central nervous system or after tumor decomposition.

Biochemical analysis

This analysis helps to clarify the primary cause of the pathology of brain tissues, helps to assess the damage caused, adjust the sequence of treatment and determine the prognosis of the disease. The main drawback of the analysis is that it is carried out only by invasive intervention, that is, they make a puncture to collect CSF.

In the normal state, the composition of the liquid contains albumin protein, while its ratio in the liquid and the percentage in plasma are very important.

This ratio is called the albumin index (normally, its value should not exceed 9 units). Its increase shows that the blood-brain barrier (the barrier between brain tissue and blood) is damaged.

Bacterioscopic and bacteriological

This study of the fluid involves obtaining it by piercing the spinal canal. Under magnification, the obtained substance or sediment, which is obtained after centrifugation, is considered.

From the final material, laboratory assistants receive smears, which they study after repainting them. It does not matter whether microorganisms are found in the CSF or not, the study will definitely be carried out.

The appointment of the analysis is carried out by the doctor necessary in various situations, if there is a suspicion of an infectious form of meningitis, in order to establish the type of irritant. The disease can also be caused by unusual flora, possibly streptococci, meningococcus is a common causative agent of the disease, as is tubercle bacillus.

A few weeks before the onset of meningitis, patients very often notice the appearance of a cough, temporary fever and a runny nose. The development of the disease can be indicated by a constant migraine of a bursting nature, which does not respond to medicinal painkillers. In this case, the body temperature can rise to high levels.

With meningococcus, a rash forms on the surface of the body, most often on the legs. Still patients often complain of a negative perception of bright light. The muscles in the neck become more rigid, as a result, a person is not able to touch his chin to the chest.

Meningitis requires urgent hospitalization with subsequent examination and urgent treatment in a hospital.

Deciphering the indicators of cerebrospinal fluid

The altered color of different intensities may be due to the mixing of erythrocytes, which appear with recent brain injuries or blood loss. Visually, the presence of red blood cells can be seen when their number is more than 600 per µl.

With a variety of disorders, inflammatory processes occurring in the body, CSF can become xanthochromic, that is, have a yellow or brownish color due to the breakdown products of hemoglobin. We should not forget about false xanthochromia - the cerebrospinal fluid is stained due to medication.

In medical practice, there is also a green tint, but only in rare cases of purulent meningitis or brain abscess. In the literature, brown color is described as a breakthrough of a craniopharyngnoma cyst in the CSF pathway.

Turbidity of the liquid may indicate the presence of microorganisms or blood cells in it. In the first case, turbidity can be removed by centrifugation.

The study of the composition of the CSF is a particularly important task, which includes a large number of different manipulations, tests and calculations, while it is necessary to pay attention to many other indicators.

After the procedure, the patient is prescribed bed rest for a day. During the following days, he may complain of migraines. This is due to the overstrain of the meninges due to the collection of fluid during the procedure.

The review presents changes in laboratory parameters of cerebrospinal fluid in the main severe diseases of the central nervous system.

MENINGITIS

The study of cerebrospinal fluid is the only method that allows you to quickly diagnose meningitis. The absence of inflammatory changes in the CSF always makes it possible to exclude the diagnosis of meningitis. The etiological diagnosis of meningitis is established using bacterioscopic and bacteriological methods, virological and serological studies.

Pleocytosis is a characteristic feature of CSF changes. According to the number of cells, serous and purulent meningitis are distinguished. With serous meningitis, cytosis is 500-600 in 1 µl, with purulent meningitis - more than 600 in 1 µl. The study must be carried out no later than 1 hour after its receipt.

According to the etiological structure, 80-90% of bacteriologically confirmed cases are Neisseria meningitides, Streptococcus pneumoniae and Haemophilus. CSF bacterioscopy, due to the characteristic morphology of meningococci and pneumococci, gives a positive result at the first lumbar puncture 1.5 times more often than culture growth.

CSF in purulent meningitis varies from slightly hazy, as if whitened with milk, to densely green, purulent, sometimes xanthochromic. In the initial stage of the development of meningococcal meningitis, there is an increase in intracranial pressure, then neutrophilic mild cytosis is noted in the cerebrospinal fluid, and in 24.7% of patients, CSF is normal in the first hours of the disease. Then, in many patients, already on the first day of the disease, cytosis reaches 12,000-30,000 per 1 μl, neutrophils predominate. The favorable course of the disease is accompanied by a decrease in the relative number of neutrophils and an increase in lymphocytes. The occurring cases of purulent meningitis with a typical clinical picture and a relatively small cytosis can be explained, probably, by a partial blockade of the subarachnoid space. A clear correlation between the severity of pleocytosis and the severity of the disease may not be observed.

The protein content in the CSF with purulent meningitis is usually increased to 0.6-10 g / l and decreases as the cerebrospinal fluid is sanitized. The amount of protein and cytosis are usually parallel, but in some cases, with high cytosis, the protein level remains normal. A high content of protein in the CSF is more common in severe forms with ependydimitis syndrome, and its presence in high concentrations during the recovery period indicates an intracranial complication (block of the CSF pathways, dural effusion, brain abscess). The combination of low pleocytosis with high protein content is a particularly poor prognostic sign.

In most patients with purulent meningitis, from the first days of the disease, a decrease in glucose levels (below 3 mmol / l) is noted; in case of death, the glucose content was in the form of traces. In 60% of patients, the glucose content is below 2.2 mmol / l, and the ratio of glucose to that in the blood in 70% is less than 0.31. An increase in glucose is almost always a prognostically favorable sign.

In tuberculous meningitis, bacterioscopic examination of the CSF often gives a negative result. Mycobacteria are more often found in fresh cases of the disease (in 80% of patients with tuberculous meningitis). Often there is a lack of mycobacteria in the lumbar punctate when they are found in the cisternal CSF. In the case of a negative or questionable bacterioscopic examination, tuberculosis is diagnosed by culture or biological test. In tuberculous meningitis, the CSF is clear, colorless, or slightly opalescent. Pleocytosis ranges from 50 to 3000 in 1 µl, depending on the stage of the disease, amounting to 100-300 in 1 µl by the 5-7th day of illness. In the absence of etiotropic treatment, the number of cells increases from the beginning to the end of the disease. There may be a sudden drop in cytosis with a second lumbar puncture performed 24 hours after the first. The cells are predominantly lymphocytes, but often at the onset of the disease there is a mixed lymphocytic-neutrophilic pleocytosis, which is considered typical for miliary tuberculosis with seeding of the meninges. Characteristic of tuberculous meningitis is the diversity of the cellular composition, when, along with the predominance of lymphocytes, neutrophils, monocytes, macrophages and giant lymphocytes are found. Later, pleocytosis acquires a lymphoplasmacytic or phagocytic character. A large number of monocytes and macrophages indicates an unfavorable course of the disease.

The total protein in tuberculous meningitis is always increased to 2-3 g / l, and earlier researchers noted that the protein increases before the appearance of pleocytosis and disappears after a significant decrease, i.e., in the first days of the disease, protein-cell dissociation takes place. Modern atypical forms of tuberculous meningitis are characterized by the absence of typical protein-cell dissociation.

With tuberculous meningitis, a decrease in glucose concentration to 0.83-1.67 mmol / l and below is noted early. In some patients, a decrease in the content of chlorides is detected. In viral meningitis, about 2/3 of cases are caused by the mumps virus and a group of enteroviruses.

In serous meningitis of viral etiology, CSF is transparent or slightly opalescent. Pleocytosis is small (rarely up to 1000) with a predominance of lymphocytes. In some patients, neutrophils may predominate at the onset of the disease, which is characteristic of a more severe course and a less favorable prognosis. Total protein within 0.6-1.6 g/l or normal. In some patients, a decrease in protein concentration due to hyperproduction of cerebrospinal fluid is detected.

CLOSED CRANIO-BRAIN INJURY

The permeability of cerebral vessels in the acute period of traumatic brain injury is several times higher than the permeability of peripheral vessels and is directly dependent on the severity of the injury. To determine the severity of the lesion in the acute period, a number of CSF and hematological tests can be used. These include: the severity and duration of the presence of hyperproteinorachia as a test characterizing the depth of dysgemic disorders in the brain and the permeability of the hematoliquor barrier; the presence and severity of erythroarchia as a test that reliably characterizes ongoing intracerebral bleeding; the presence within 9-12 days after the injury of pronounced neutrophilic pleocytosis, which is an indication of the unreactivity of tissues that limit the cerebrospinal fluid spaces and inhibition of the sanitizing properties of the cells of the arachnoid membrane or infection.

Concussion: CSF is usually colorless, clear, contains no or few red blood cells. On the 1st-2nd day after the injury, cytosis is normal, on the 3rd-4th day a moderately pronounced pleocytosis appears (up to 100 in 1 μl), which decreases to normal numbers on the 5th-7th day. In the liquorogram, lymphocytes with the presence of a small number of neutrophils and monocytes, macrophages, as a rule, are absent. The protein level is normal on days 1-2 after the injury, on days 3-4 it rises to 0.36-0.8 g/l and returns to normal by days 5-7.

Brain contusion: the number of red blood cells ranges from 100 to 35,000, and with a massive subarachnoid hemorrhage, it reaches 1-3 million. Depending on this, the color of the CSF can be from grayish to red. Due to irritation of the meninges, reactive pleocytosis develops. With bruises of mild and moderate severity, pleocytosis for 1-2 days is on average 160 per 1 μl, and in severe cases it reaches several thousand. On days 5-10, pleocytosis significantly decreases, but does not reach the norm in the next 11-20 days. The liquorogamma contains lymphocytes, often macrophages with hemosiderin. If the nature of pleocytosis changes to neutrophilic (70-100% of neutrophils), purulent meningitis has developed as a complication. The protein content in mild and moderate severity is on average 1 g/l and does not return to normal by 11-20 days. With severe brain damage, the protein level can reach 3-10 g / l (often ends in death).

With a traumatic brain injury, the energy metabolism of the brain switches to the path of anaerobic glycolysis, which leads to the accumulation of lactic acid in it, and, ultimately, to brain acidosis.

The study of the parameters reflecting the state of the energy metabolism of the brain makes it possible to judge the severity of the course of the pathological process. Decreased arteriovenous difference in pO2 and pCO2, increased brain glucose consumption, increased venoarterial difference in lactic acid and its increase in cerebrospinal fluid. The observed changes are the result of a violation of the activity of a number of enzyme systems and cannot be compensated by the blood supply. It is necessary to stimulate the nervous activity of patients.

HEMORRHAGIC STROKE

The color of the cerebrospinal fluid depends on the admixture of blood. In 80-95% of patients, during the first 24-36 hours, the CSF contains a clear admixture of blood, and at a later date it is either bloody or xanthochromic. However, in 20-25% of patients with small lesions located in the deep parts of the hemispheres, or in the case of blockade of the CSF pathways due to rapidly developing cerebral edema, erythrocytes in the CSF are not detected. In addition, erythrocytes may be absent during a lumbar puncture in the very first hours after the onset of hemorrhage, while the blood reaches the spinal level. Such situations are the reason for diagnostic errors - the diagnosis of "ischemic stroke". The greatest amount of blood is found when blood breaks into the ventricular system. Removal of blood from the cerebrospinal fluid begins from the very first day of the disease and lasts for 14-20 days with craniocerebral injuries and strokes, and with cerebral aneurysms up to 1-1.5 months and does not depend on the massiveness of the hemorrhage, but on the etiology process.

The second important sign of CSF changes in hemorrhagic stroke is xanthochromia, which is detected in 70-75% of patients. It appears on the 2nd day and disappears 2 weeks after the stroke. With a very large number of red blood cells, xanthochromia may appear after 2-7 hours.

An increase in protein concentration is observed in 93.9% of patients and its amount ranges from 0.34 to 10 g/l and above. Hyperproteinorachia and elevated bilirubin content can persist for a long time and, along with liquorodynamic disorders, can cause meningeal symptoms, in particular headaches, even 0.5–1 year after subarachnoid hemorrhage.

Pleocytosis is detected in almost 2/3 of patients, it has an increasing character within 4-6 days, the number of cells ranges from 13 to 3000 in 1 μl. Pleocytosis is associated not only with a breakthrough of blood into the liquor pathways, but also with the reaction of the meninges to the outflowing blood. It seems important to determine the true cytosis of CSF in such cases. Sometimes, with hemorrhages in the brain, cytosis remains normal, which is associated with limited hematomas without a breakthrough into the liquor space, or with unresponsiveness of the meninges.

With subarachnoid hemorrhages, the admixture of blood can be so great that the cerebrospinal fluid is visually almost indistinguishable from pure blood. On the 1st day, the number of erythrocytes, as a rule, does not exceed 200-500 x 109 / l, in the future their number increases to 700-2000 x 109 / l. In the very first hours after the development of small subarachnoid hemorrhages, a clear cerebrospinal fluid can be obtained with a lumbar puncture, but by the end of the 1st day, an admixture of blood appears in it. The reasons for the absence of blood in the CSF may be the same as in hemorrhagic stroke. Pleocytosis, mainly neutrophilic, over 400-800x109/l, by the fifth day is replaced by lymphocytic. Within a few hours after the hemorrhage, macrophages may appear, which can be considered markers of subarachnoid hemorrhage. The increase in total protein usually corresponds to the degree of hemorrhage and can reach 7-11 g/l and higher.

ISCHEMIC STROKE

CSF is colorless, transparent, in 66% the cytosis remains within the normal range, in the rest it rises to 15-50x109/l, in these cases characteristic cerebral infarctions are detected, close to the CSF pathways. Pleocytosis, predominantly lymphoid-neutrophilic, is due to reactive changes around extensive ischemic foci. In half of the patients, the protein content is determined in the range of 0.34-0.82 g/l, less often up to 1 g/l. An increase in protein concentration is due to necrosis of the brain tissue, an increase in the permeability of the blood-brain barrier. The protein content may increase by the end of the first week after a stroke and last more than 1.5 months. Quite characteristic of ischemic stroke is protein-cell (an increase in protein content with normal cytosis) or cell-protein dissociation.

ABSCESS OF THE BRAIN

The initial phase of abscess formation is characterized by neutrophilic pleocytosis and a slight increase in protein. As the capsule develops, pleocytosis decreases and its neutrophilic character is replaced by lymphoid, and the greater the development of the capsule, the less pronounced pleocytosis. Against this background, the sudden appearance of a pronounced neutrophilic pleocytosis indicates a breakthrough of the abscess. If the abscess was located near the ventricular system or the surface of the brain, the cytosis will be from 100 to 400 in 3 µl. Minor pleocytosis or normal cytosis may occur when the abscess has been delimited from the surrounding brain tissue by a dense fibrous or hyalinized capsule. The zone of inflammatory infiltration around the abscess in this case is absent or weakly expressed.

CNS TUMORS

Along with protein-cell dissociation, which is considered characteristic of tumors, pleocytosis may occur with a normal protein content in the cerebrospinal fluid. With gliomas of the cerebral hemispheres, regardless of their histology and localization, an increase in protein in the cerebrospinal fluid is observed in 70.3% of cases, and in immature forms - in 88%. The normal or even hydrocephalic composition of the ventricular and spinal fluid can occur in both deep-seated and gliomas growing into the ventricles. This is mainly observed in mature diffusely growing tumors (astrocytomas, oligodendrogliomas), without obvious foci of necrosis and cyst formation and without gross displacement of the ventricular system. At the same time, the same tumors, but with a gross displacement of the ventricles, are usually accompanied by an increase in the amount of protein in the cerebrospinal fluid. Hyperproteinorachia (from 1 g / l and above) is observed in tumors located at the base of the brain. In pituitary tumors, the protein content ranges from 0.33 to 2.0 g/l. The degree of shift of the proteinogram is directly dependent on the histological nature of the tumor: the more malignant the tumor, the grosser the changes in the protein formula of the CSF. Beta-lipoproteins that are not normally found appear, the content of alpha-lipoproteins decreases.

In patients with brain tumors, regardless of their histological nature and localization, polymorphic pleocytosis often occurs. The cellular reaction is due to the peculiarities of the biological processes occurring in the tumor at certain stages of its development (necrosis, hemorrhage), which determine the reaction. Surrounding tumor tissues of the brain and membranes. Tumor cells of the cerebral hemispheres in the fluid from the ventricles can be found in 34.4%, and in the spinal cerebrospinal fluid - from 5.8 to 15% of all cases. The main factor causing the entry of tumor cells into the CSF is the nature of the structure of the tumor tissue (poverty of the connecting stroma), the absence of a capsule, as well as the location of the neoplasm near the CSF spaces.

CHRONIC INFLAMMATORY DISEASES (arachnoiditis, arachnoencephalitis, periventricular encephalitis)