Analysis of the CSF ( cerebrospinal fluid ) - Causes, Symptoms and Treatment .MF .

August 12, 2017 17:52 | Laboratory

Liquor (cerebrospinal or spinal fluid, CSF) - biological fluid, necessary for the functioning of the central nervous system.His study is one of the most important types of laboratory tests.It consists of pre-analytical phase (preparation of the subject, gathering material and its delivery to the laboratory), analytical (the actual implementation of the study) and postanalytical (interpretation of the result).Only the correct implementation of all the manipulations on each of these stages determines the quality of the analysis.

cerebrospinal fluid (CSF) is formed in the choroid plexus of the brain ventricles.In the adult human at the same time subarhnoidalnyh spaces and in the ventricles of the brain circulates 110-160 ml CSF in the spinal canal - 50-70 ml.Liquor is formed continuously at a rate of 0.2-0.8 ml / min, depending on the intracranial pressure.In the day in a healthy person is formed 350-1150 ml CSF.

Liquor obtained by puncture of the spinal canal, often - lumbar - according to the metho

d well known to neurologists and neurosurgeons.His first drops removed ( "road" the blood).Then, the liquor collected at least two tubes: tube in conventional (chemical, centrifuge) for general clinical and chemical analysis, sterile - for bacteriological examination.On the referral form to the study of CSF physician should specify not only the name of the patient, but also the clinical diagnosis and research objective.

Keep in mind that the CSF delivered to the laboratory the samples shall be protected from pergrevaniya or cooled and samples are designed to detect bacterial polysaccharides serogicheskih tests should be warm in a water bath for 3 minutes.

Actually laboratory examination of cerebrospinal fluid (the analytical phase) is conducted according to the rules adopted in the clinical laboratory diagnostics in the analysis of any biological fluids, and includes the following steps:

- macroscopic analysis - assessment of physicochemical properties (size, color, character),
- counting the number of cells,
- microscopy native drug and stained cytology drug;
- biochemical,
- microbiological examination (if indicated).

We find it appropriate and informative in some cases supplement the study of CSF immunological and possibly - other tests, the significance of which is discussed in the literature.

Explanation indicators liquor

Normal CSF colorless and porozrachna (as distilled water, in comparison with which, and usually describe the physical properties of liquor).

grayish or grayish-green liquor is usually caused by an admixture of bacteria and white blood cells.The red color of varying intensity CSF (eritrohromiya) due to an admixture of red blood cells encountered in fresh hemorrhages or brain injury.Visually pristutstvuyut erythrocytes detected by their content in more than 500-600 ml.

When pathological processes liquid can be ksantohromnoy - painted in yellow or yellow-brown color of the products of hemoglobin breakdown.Also consider xanthosis false - color liquor caused by drugs.Less frequently we meet greenish CSF (purulent meningitis, brain abscess).The literature describes the color and korchnevy liquor - the breakout craniopharyngioma cysts in the cerebrospinal fluid path.

liquor turbidity may be due to an admixture of blood cells or microorganisms.In the latter case, the turbidity can be removed by centrifugation.When the content in the CSF increased the number of coarse protein it becomes opalescent.

Relative density of the cerebrospinal fluid obtained by lumbar puncture, 1,006-1,007.When inflammation of the meninges, brain injuries relative density of cerebrospinal fluid increases to 1,015.Decreases it with overproduction of cerebrospinal fluid (hydrocephalus).

When elevated levels of fibrinogen in the CSF is formed fibrinous film or a clot that occurs more frequently in tubercular meningitis.Sometimes the liquid tube is left at room temperature for a day (if necessary to accurately set - Do film formed?).In the presence of fibrinous film her dissecting needle is transferred onto a glass slide and stained with Ziehl-Nielsen or another method for identifying mycobacteria.Normal CSF 98-99% water.

Nevertheless, the study of its chemical composition is an important task.It involves determining the protein level, chlorides and glucose, and supplemented by other parameters in some cases.

protein in the cerebrospinal fluid

More than 80% of CSF protein comes from the plasma by ultrafiltration. normal protein content in various portions: a ventricular - 0.05-0.15 g / l tsisternalnom 0.15-0.25 g / L, lumbar 0.15-0.35 g / l. To determine the protein concentration in cerebrospinal fluid can be used any of standardized methods (sulfosalicylic acid and ammonium sulfate, and others).Increased protein in the cerebrospinal fluid (giperproteinarhiya) may be due to various pathogenetic factors (Table 1).

study of CSF protein makes it possible not only to clarify the nature of the pathological process, but also to assess the condition of the blood-brain barrier.Indicator for these purposes may be albumin, provided that the level is determined in CSF immunochemical methods.Determination of albumin is carried out in connection with the fact that he, as the blood protein is not synthesized locally and therefore may be a "marker" of immunoglobulins, penetrated from the bloodstream as a result of impaired permeability barrier.Simultaneous determination of albumin in serum (plasma) blood and CSF albumin allows us to calculate the index:

When the intact blood-brain barrier, the index of less than 9, with its moderate damage - 9-14, with a noticeable - 14-30, with severe damage- 30-100, and an increase of more than 100 indicates a complete failure of the barrier.

In recent years, increased interest in specific CNS proteins liquor - neuron enolase, protein S-100, myelin basic protein (MBP) and some others.One of the most promising among them for clinical purposes seems MBP.In the normal CSF it is practically absent (less than the concentration of 4 mg / l) and appears only under pathological conditions.This lab feature is not specific to certain clinical entities, but reflects the size of the lesion (mostly associated with the destruction of the white matter).Some authors consider it a promising definition of MBP in CSF for monitoring neuroAIDS.Unfortunately, there remain problems associated with the direct determination of the protein concentration.

glucose in the CSF

Glucose contained in the normal cerebrospinal fluid concentration of 2.00-4.18 mmol / l. This value is subject to large fluctuations even in a healthy person, depending on the mode of food, exercise and other factors.To properly assess the level of glucose in the CSF to simultaneously determine its level in the blood, where normally it is 2 times higher.Elevated levels of blood glucose (giperglikoarhiya) occurs in diabetes mellitus, acute encephalitis, ischemic circulatory disorders and other diseases.Gipoglikoarhiya seen with meningitis various etiology or aseptic inflammation, tumor lesions of the brain and the membranes, at least - with the herpes infection, subarachnoid hemorrhage.

some advantage over glucose as a diagnostic marker is lactate (lactic acid) as its concentration in the cerebrospinal fluid (1.2-2.1 mmol / l) is independent from that in blood.Its level is significantly increased in various conditions associated with impaired energy metabolism - meningitis, especially - caused by Gram-positive flora, brain hypoxia and some others.

chloride in cerebrospinal fluid

Chloride - content in the normal cerebrospinal fluid - 118-132 mg / dL. increasing concentration in CSF is observed in case of violation of their elimination from the body (kidney, heart), degenerative diseases and tumors of the central nervous system.Reducing the chloride content is marked with encephalitis and meningitis.

Enzymes in CSF

Liquor is characterized by low activity of enzymes contained therein.Modifying enzyme activity in the CSF in various diseases are generally nonspecific and parallel changes in blood described in these diseases (Table 2).Different approach deserves interpretation of changes in the activity of creatine phosphokinase (CPK).This enzyme is presented in the tissues of the three factions, which are characterized not only by molecular differences, but also the nature of the distribution in tissues: CK-MB (myocardium), CK-MM (muscle), creatine kinase-BB (brain).If the total activity of CK in the cerebrospinal fluid is not essential diagnostic value (it can be increased with the tumor, cerebral infarction, epilepsy and other diseases), the fraction of CK-BB is relatively specific marker of damage to brain tissue and its activity in CSF correlate with the Glasgow scale.

number of cells and CSF cytogram

In the study of biological fluids and CSF including typically count the number of cells in the cytogram and smears stained azureozinom (Romanowsky-Giemsa Nocht, Pappenheim).Counting of cellular elements in the cerebrospinal fluid (the definition of cell count) produced by a Fuchs-Rosenthal chamber, pre-breeding of his reagent Samson 10 times.Use of the given dye, rather than any other.It allows the cells to stain for 15 minutes and to maintain unaltered cells 2 hours.

number of cells throughout the cell is divided into three, so cell count obtained in 1 mm.For greater accuracy, consider cell count in three chambers.When Fuchs-Rosenthal chamber absence, you can use the camera Goryaeva by counting the cells throughout the grid in the three chambers, the result is multiplied by 0.4.Until now, there are discrepancies in units cytosis - number of cells in the chamber, in 1 mm or 1 liter.Probably, it is expedient to express all the cells in a cell count amount of microliters.To count the number of leukocytes and erythrocytes in CSF may be employed and automated systems.

Increased cell count in the CSF (pleocytosis) appears more often in inflammatory diseases, to a lesser extent - with irritation of the meninges.The most pronounced pleocytosis seen with bacterial infections, fungal brain lesions and tuberculous meningitis.In epilepsy, arachnoiditis, hydrocephalus, degenerative processes and some other diseases of the central nervous system cell count remains normal.

staining cells native preparation reagent Samson allows enough reliably differentiated cells.But the more accurate their morphological characteristics achieved after fixing and staining the prepared cytologic preparations.The modern approach to the preparation of such products involves the use of cytospin.However, even in the United States they have only 55% of laboratories.Therefore, in practice, a simpler way is used - the deposition on a glass cell.Preparations should be well air dried and then painted.

are counting cell elements in stained preparation.They are mainly represented by blood cells (usually - lymphocytes and neutrophils, at least - monocytes, eosinophils, basophils) can meet the plasma and mast cells, macrophages, granular balls (degenerative form of a special type of macrophage - lipofagov able to fatty degeneration) cells arahnoendoteliya, epindimy.The morphology of these cell elements are generally well-known physicians and laboratory diagnosis is described in detail in many textbooks.The level and nature of pleocytosis cytogram liquor permit to clarify the nature of the pathological process (Table 3).

leukocytosis often accompanied by acute infection (local and diffuse meningitis).Eosinophilia CSF is rare - when the brain echinococcosis, eosinophilic meningitis.Eosinophilia liquor usually does not correlate with the number of eosinophils in the blood.Lymphocytic pleocytosis CSF occurs in viral meningitis, multiple sclerosis, chronic phase of tuberculous meningitis, after operations on the meninges.When pathological processes of the nervous system marked polymorphism lymphocytes, among which there are activated.They are characterized by the presence of abundant cytoplasm with single palely azurophilic granules, some cells have otshnurovku or fragmentation of the cytoplasm (clasmatosis).Plasma cells appear in cytogramme in viral or bacterial meningitis, inflammation smoldering, during recovery from neurosyphilis.Monocytes undergoing degeneration in the cerebrospinal fluid faster lymphocytes observed in multiple sclerosis, progressive panencephalitis, chronic smoldering inflammation.Macrophages - "orderlies" liquor, appear with hemorrhages, infections, traumatic and ischemic necrosis.

Sometimes CSF detected abnormal cells - the elements which by their morphological features can not be attributed to specific cellular forms.Atypical cells are found in chronic inflammatory processes (tuberculous meningitis, multiple sclerosis, etc.), and often they are tumor cells.Probability findings of tumor cells in the cerebrospinal fluid in brain tumors is small (less than 1.5%).Detection of blast cells in the CSF with hematological malignancies suggests neuroleukemia.

When analyzing the composition of the liquor is important to evaluate the ratio of protein and cellular elements (dissociation).When cell-expressed protein dissociation marked pleocytosis with normal or slightly increased protein content.This is typical of meningitis.Belkovokletochnaya dissociation characterized giperproteinarhiey with normal cell count.This condition is typical of stagnant processes in the cerebrospinal fluid pathways (tumor, arachnoiditis, etc.).

clinical situations sometimes require counting the number of red blood cells in the cerebrospinal fluid spotting (bleeding volume for objectification).Erythrocyte count lead as well as in blood.As indicated above, the liquor color change if contained in a 1 L 500-600 erythrocytes noticeable staining occurs in the presence of about 2000, and when it becomes a hemorrhagic erythrocyte level of more than 4000 / L.

Microbiological examination of cerebrospinal fluid

One of the most frequent diseases of the CNS is a purulent meningitis.In such cases, particular relevance mikorobiologicheskoe study.It includes an indicative test - bacterioscopy drugs and classical culture techniques.Bacterioscopy CSF has a limited diagnostic value, particularly in the preparation of clear CSF.Smear prepared from sludge liquor, obtained by centrifugation, okarshivayut methylene blue or Gram, although some authors believe that the latest version of the color "traumatize" shaped elements and creates artifacts.When meningitis and abscesses found diverse flora, corresponding to the nature of the disease.Regardless of the results of microscopy diagnosis of bacterial meningitis must be confirmed by bacteriological culture that becomes the determining factor in the diagnosis of this group of diseases, and the choice of adequate therapy.It is conducted in accordance with the Order № 375 of the Ministry of Health of the Russian Federation 23.12.98 "On measures to strengthen the surveillance and prevention of meningococcal infection and purulent bacterial meningitis."The most common cause of bacterial meningitis is a Gram-negative diplococcus Neisseria meningitidis, which is 80% of the cases can be detected even when microscopy.

Microscopy liquor

Normally only present in the cerebrospinal fluid lymphocytes and monocytes. In various diseases and pathological conditions in the CSF may appear other types of cells.

Lymphocytes are similar in size to red blood cells.Lymphocytes have a large nucleus and a narrow rim of cytoplasm unpainted.Normally, in the cerebrospinal fluid contains 8-10 lymphocyte cells.Their number increases in tumors of the central nervous system.Lymphocytes are found in chronic inflammation of the membranes (tuberculous meningitis, arachnoiditis tsistitserkoznom).

Plasma cells in the cerebrospinal fluid.