Examination of synovial fluid. Laboratory diagnostics of synovial fluid in the diagnosis of joint diseases. Visual analysis of synovial fluid

Why perform a synovial fluid analysis?

In situations of primary medical care analysis data synovial fluid(SG) allow you to determine the specialist to whom the patient should be referred.

• If the GS is non-inflammatory, see an orthopedist.
• If it’s inflammatory, see a rheumatologist.

Diagnostic value of synovial fluid analysis

• Inflammatory or non-inflammatory pathology
• Crystalline inflammation or sepsis, or exacerbation
• Helps identify groups of diseases based on cell number and cell type
• Determination of the type of prosthetic failure
• Prognostic value
• Orthopedic intervention
• Stage specific disease
• Therapy monitoring. In particular, refusal of monoclonal antibody therapy.

In Fig. 1 and 2 reflect the algorithm for diagnosing joint diseases based on data from the analysis of synovial fluid

Pathological changes in the tissues surrounding the diseased joint are reflected in the volume, cellular composition and the presence of solid particles in fluid. Inflammatory joint diseases, differing in etiology, have characteristic cellular patterns that can be recognized and used in the diagnosis of a specific disease or group of diseases (Fig. 1, 2). In order to identify these differences, it is necessary to correctly select and properly store SF in order to minimize autolytic changes and degradation of characteristic cells. EDTA is used as an anticoagulant. Storage at 4°C is well tolerated by the fluid and gives excellent diagnostic results. Almost adequate results can be obtained up to 48 hours from aspiration, but more long-term storage even at 4°C, as a rule, only crystals and particles can be identified. Most cells undergo lysis.

Cytological analysis of synovial fluid

Fat cells can be found in the analysis of the SF of most patients with joint disease, but most often they are observed in inflammatory arthritis in patients with seronegative spondyloarthropathies and in non-inflammatory joint lesions associated with trauma.

This type of CL is often detected when analyzing the SF of patients with intra-articular hemorrhage or arthrography, as well as when allergic reaction to injected drugs, such as artificial fluid.

General clinical examination of joint fluid includes determination physical and chemical properties fluids and microscopic examination of cellular elements. Reference parameters of synovial fluid are presented in the table.

Table Reference indicators of synovial fluid

The study of synovial fluid plays an important role in clarifying the nature of the process in the affected joint. Indications for joint puncture: monoarthritis unknown etiology, discomfort in the affected joint (with established diagnosis), the need to monitor the effectiveness of treatment for infectious arthritis, for differential diagnosis arthritis and arthrosis, since the choice of a program for further examination and treatment of the patient depends on this. Indicators of synovial fluid in arthritis and arthrosis are presented in the table.

Table Changes in synovial fluid in arthritis and arthrosis

IN clinical practice Most often, joint damage is detected in the following diseases.

Infectious arthritis is divided into gonococcal (arising due to dissemination gonococcal infection) and non-gonococcal - most often caused by Staphylococcus aureus (70% of cases) and Streptococcus, as well as in many viral infections(especially with rubella, infectious mumps, infectious mononucleosis, hepatitis) and Lyme disease, caused by the spirochete Borrelia burgdorferi, transmitted by tick bites. Septic arthritis can be caused by fungi and mycobacteria.

Synovitis caused by crystals. Crystal deposition in joints or periarticular tissues underlies gout, pseudogout and apatite disease. To diagnose gout and pseudogout, polarization microscopy of the sediment obtained by centrifugation of synovial fluid is performed. Use a polarizing microscope with a red filter. The needle-shaped urate crystals characteristic of gout glow yellow (if their long axis is parallel to the axis of the compensator) and have strong negative birefringence. They are found both in synovial fluid and in neutrophils. Crystals of calcium pyrophosphate dihydrate, detected in pseudogout, have a variety of shapes (usually diamond-shaped), glow blue and are characterized by a weak positive double reflex

laziness. Complexes containing hydroxyapatite (specific for apatite disease), as well as complexes containing basic calcium and phosphorus salts, can only be detected using electron microscopy. It should be emphasized that hyperuricemia should not be considered specific sign gout, and calcification of the joints - pseudogout, in any case, to confirm the diagnosis, a study using polarization microscopy is necessary.

Rheumatoid arthritis. If inflammation of one joint is clearly predominant, a study of the synovial fluid should be carried out to exclude an infectious genesis of its origin, since rheumatoid arthritis predisposes to infectious arthritis.

Spondyloarthropathy. This group includes a number of diseases that are characterized by asymmetric oligoarthritis. Synovial fluid examination is performed to exclude septic arthritis. The following spondyloarthropathies are distinguished.

■ Ankylosing spondylitis. From peripheral joints The hip and shoulder are most often affected.

■ Arthritis with inflammatory diseases intestines: in 10-20% of patients suffering from Crohn's disease and nonspecific ulcerative colitis joint damage develops, especially often in the knees and ankles.

■ Reiter's syndrome and reactive arthritis developing after urogenital or intestinal infections.

■ Psoriatic arthritis develops in 7% of patients with psoriasis.

SCV. Changes in the joint fluid can be both non-inflammatory (arthrosis) and inflammatory (arthritis).

Osteoarthritis is a degenerative disease of the joints, characterized by the “wear and tear” of articular cartilage with subsequent bone growths along the edges of the articular surfaces.

Changes in synovial fluid during various pathological processes are reflected in the table.

Most pronounced changes found in synovial fluid in bacterial arthritis. Externally, synovial fluid may look like pus; the cell content reaches 50,000-100,000 in 1 μl, of which neutrophils make up more than 80%. Sometimes in the first 24-48 hours of acute arthritis, the number of cellular elements may be less than 25,000 in 1 μl.

In patients with rheumatoid arthritis, examination of synovial fluid is important to confirm the diagnosis and determine the local activity of the inflammatory process. At rheumatoid arthritis the number of leukocytes in the synovial fluid increases to 25,000 per 1 μl due to neutrophils (25-90%), the protein content reaches 40-60 g/l. In the cytoplasm of leukocytes, inclusions and vacuoles similar to a bunch of grapes (ragocytes) are found. These cells contain phagocytosed material - lipid or protein substances, rheumatoid factor, immune complexes, complement. Ragocytes are also found in other diseases - rheumatic, psoriatic, arthritis, SLE, bacterial arthritis, gout, but not in such quantities as in rheumatoid arthritis.

Table Changes in synovial fluid in various pathological processes

For joint diseases, it is necessary to undergo comprehensive examination to identify the cause and nature of the inflammatory process. One of critical analyzes- This is a study of synovial fluid. The procedure for taking fluid for analysis is unpleasant, but the study is the most effective way diagnosis, and is necessary for drawing up a treatment regimen.

One of the most important tests is the study of synovial fluid

Synovial fluid, often called joint fluid, acts as a lubricant between cartilage. Thanks to this substance, shock absorption is provided, reducing the force of impact and the load on the joints during movement. Synovial fluid additionally serves as transport for nutrients, supporting elasticity cartilage tissue.

In case of any disturbances in the functioning of the joint and inflammatory processes, the first changes affect the joint fluid. By examining the synovial fluid, it is possible to quickly diagnose accurate diagnosis on initial stages development of joint pathologies.

Indications for synovial fluid analysis:

• pain syndrome;
• violation motor activity joint;
• sudden lameness;
• morning joint stiffness.

A study of synovial fluid is prescribed for rheumatoid arthritis or if this disease is suspected, or inflammation of the joint capsule. This study is necessary to exclude or confirm the bacterial nature of the inflammatory process.

To take no a large number of fluid for analysis, puncture is performed. The procedure is carried out in two stages. First, the patient is thoroughly disinfected at the puncture site and this area is injected with an anesthetic to eliminate pain. Applies only local anesthesia. Then a special needle, hollow inside, is inserted into the joint cavity, with the help of which a small amount of fluid is pumped out.

The duration of the entire procedure is no more than 5 minutes. The liquid drawn into a sterile syringe is immediately sent to the laboratory.

The puncture cannot be performed only if the epidermis around the needle insertion area is infected. With exacerbation of chronic dermatological diseases The procedure is postponed until remission is achieved. Puncture synovial membrane to collect fluid from the joint is not done in general in serious condition which is accompanied by fever or intoxication.

The puncture is used simultaneously as a diagnostic and healing method. When fluid is collected from the joint, the pressure in the synovium decreases, which instantly eliminates pain due to inflammation. Also, using a puncture, special painkillers or anti-inflammatory drugs can be administered to relieve the symptoms of arthritis.

Assessment of synovial fluid composition

Synovial fluid analysis helps identify the cause of joint dysfunction

Synovial fluid in a healthy joint is a light yellow, viscous lubricant. Its amount can vary from 1 to 4 ml. During the analysis of the synovial fluid of the knee joint, about 1 ml of fluid is collected for testing.

Analysis includes:

• visual assessment of the liquid and its physical properties;
• determination of chemical composition;
• staining the smear and conducting microscopic examination the received drug;
• bacterial culture of the liquid.

The combination of these stages makes it possible to conduct a comprehensive assessment of joint function and identify all possible violations. Deciphering the cytological examination of synovial fluid will allow us to better understand its significance and possible disturbances in its composition.

Visual analysis of fluid: norm and pathology

Deciphering a visual analysis of synovial fluid helps to identify the cause of joint dysfunction. This is necessary to determine the inflammatory or non-inflammatory nature of the disease.

The number of leukocytes is determined per 1 μl of the test drug.

Non-inflammatory pathological process in the joint capsule is observed in osteoarthritis. This analysis result is also typical for systemic lupus erythematosus and arthrosis that develops against the background of injuries.

Inflammation in the joints is characteristic of rheumatoid and gouty arthritis. These diseases are accompanied by stiffness in the joints in the morning, immediately after sleep, and severe pain.

Septic inflammatory process in the joints develops against the background of infection with tuberculosis, gonorrhea and other infections. It is also called purulent or infectious inflammation.

Chemical analysis

Cellular elements are assessed using chemical analysis

Chemical analysis of synovial fluid determines the presence of protein, glucose, uric acid. In healthy joints there are no protein compounds. Their presence indicates arthritis due to gout or psoriasis. The amount of protein is assessed by filling the field of view of the microscope.

Glucose in synovial fluid indicates complications diabetes mellitus. To avoid false positive result, the analysis is carried out on an empty stomach in the morning. You should definitely refuse to eat at least 8 hours before the puncture.

In severe inflammation, a significant amount of glucose is found in the joint fluid, which is normally present in the joints in minute quantities.

Uric acid is found in synovial fluid only in one disease - gout. Because gouty arthritis accompanied by specific symptoms, determination of the level of uric acid in the joints is an auxiliary, but not mandatory, study for such a diagnosis.

Microscopy

The purpose of microscopic analysis is to count crystals and cellular elements in the composition of the material under study. To do this, the sample is placed under a microscope, stained with a special preparation and carefully examined. The assessment of cellular elements is carried out visually.

Normally, the liquid contains no crystals. The reason for their formation depends on the type of crystalline compounds indicated in the analysis results. With gout, there is a large amount of sodium urate. The presence of cholesterol in the joint fluid indicates arthritis of any nature; calcifications are found when severe forms rheumatoid arthritis.

Cytological analysis

Cytological analysis evaluates total number cells

Cytology is minimum required when examining joint fluid. To count cells, special staining preparations and additional equipment are usually used, which allows you to accurately determine the type and number of changed cells. Cytological analysis is simpler, since the number of cells is assessed visually, based on the volume of the slide. This method only allows you to determine the nature of the disease by the number of leukocytes. An increase in the number of these cells indicates inflammation.

Cytological analysis evaluates the total number of cells. In this case, the analysis allows us to identify the inflammatory, non-inflammatory and purulent nature of the disease. In other words, chemical analysis and cytological analysis- this is practically the same thing, only the results of chemical analysis are more detailed.

By staining the drug and placing it in a special centrifuge, it is possible to identify crystals in the liquid. This reveals the presence of needle-shaped and quadrangular crystals.

Diseases that can be diagnosed during an extended cytological examination of a stained specimen:

• all types of arthritis;
• gout;
• arthrosis;
• deposits of calcium salts in joints;
• purulent and infectious inflammation of the joints.

Cytological examination is carried out quite simply and quickly, which makes it one of the first ways to assess joint health.

Bacterial culture

If microscopic analysis and cytology revealed septic inflammation, additional bacterial culture of the joint fluid is necessary. This analysis allows you to accurately identify the type of pathogen infectious inflammation, on the basis of which you can select the most effective scheme therapy.

To carry out the analysis, the joint fluid is placed in a special medium filled with a nutrient solution. In this environment any pathogenic microorganisms They mature quickly and their population increases. A few days later, the laboratory technician evaluates the composition of the liquid by placing a small amount of the “ripened” drug on a glass slide under a microscope. The causative agent of the disease will be those bacteria or fungi, the number of which has increased as much as possible during their stay in the nutrient medium.

Purulent inflammation of the joints must be treated with antibiotics. Bacterial culture allows you to identify the type of pathogen, on the basis of which the doctor can select effective antibacterial therapy.

Additionally, during the study, pathogenic bacteria can be analyzed for sensitivity to antibiotics.

Study of synovial fluid placed in a special nutrient medium, takes several days, since pathogenic agents mature rather slowly. Usually results are ready in 3-7 days, but in some cases it may take longer, up to two weeks.

Additional examinations

X-rays of joints can exclude damage to cartilage tissue.

Despite the informative nature of the analysis, examination of the joint fluid is prescribed only after a preliminary diagnosis has been made. For pain in the joints and impaired mobility, the patient is primarily advised to undergo the following examinations:

• blood analysis;
• radiography of joints;
• MRI and ultrasound.

A blood test for rheumatoid factor is required. High level this immunoglobulin indicates the autoimmune nature of the disease, which is typical for rheumatoid arthritis.

In some cases, inflammation occurs in the joint, but the rheumatoid factor does not increase. General and biochemical analysis blood.

X-rays of joints can help rule out damage to cartilage tissue. MRI and ultrasound reveal the involvement of surrounding tissues in the inflammatory process and help determine the presence of calcifications in the joints.

Which doctor should I contact after receiving the test results?

In the vast majority of cases primary diagnosis is carried out by a general practitioner or family doctor. This specialist will refer the patient for standard examinations - a blood test for rheumatic factor, x-ray of the joints, and a biochemical blood test to determine the level of uric acid.

If the inflammatory nature of the disease is confirmed, the doctor will refer the patient to a rheumatologist. This specialist will select the treatment regimen. In addition, specific laboratory research for joint diseases, a rheumatologist is also prescribed to detect changes in the composition of the synovial fluid.

If there is no inflammation, joint disorders may be associated with degeneration of cartilage tissue or previous injuries. In this case, treatment should be carried out by an orthopedic surgeon.

Possible complications of puncture

Risks depend on the professionalism of the doctor and preliminary examinations

Synovial fluid examination requires puncture of the joint capsule. The procedure itself has a minimum of contraindications and does not require any preparation other than refusing to eat 8 hours before the test.

When performing a puncture, anesthetics, iodine preparations, and antiseptics are used. After taking the liquid, apply a pressure bandage to the puncture site, having previously treated the skin with an antiseptic. A tight bandage should be worn all day and then replaced with a loose-fitting one.

Despite its apparent simplicity, puncture is not safe. In some cases, the following complications arise:

• internal infection of the joint;
• bleeding when a vessel is damaged;
• ligament damage and mobility impairment;
• pain due to nerve damage.

Joint infection is rare complication. The risk of infection increases with repeated puncture of the synovial membrane. Bleeding due to vascular damage requires additional measures from medical personnel, since the blood enters directly into the synovium.

Severe complications, as a result of which health deteriorates and joint mobility is impaired, are observed in isolated cases. The risks of complications largely depend on the professionalism of the doctor and preliminary examinations.

1

Studying biochemical parameters The composition of the synovial fluid of the knee joint of people of different sexes and ages normally did not reveal statistically significant differences in the indicators of the protein spectrum and carbohydrate-containing compounds of the synovial fluid knee joints healthy person based on gender and age. IN this study the closest correlations with human age are the indicators of γ-globulins and sialic acids.

synovial fluid

hyaluronic acid

total protein

sialic acids

1. Bazarny V.V. Synovial fluid (clinical and diagnostic value laboratory analysis) / V.V. Market. – Ekaterinburg: Publishing House of the UGMA, 1999. – 62 p.

2. Biochemical studies of synovial fluid in patients with diseases and injuries large joints: manual for doctors / compiled by: V.V. Trotsenko, L.N. Furtseva, S.V. Kagramanov, I.A. Bogdanova, R.I. Alekseeva. – M.: TsNIITO, 1999. – 24 p.

3. Gerasimov A.M. Biochemical diagnostics in traumatology and orthopedics / A.M. Gerasimov L.N. Furtseva. – M.: Medicine, 1986. – 326 p.

4. Diagnostic value of determining hexokinase activity in the synovial fluid of the knee joints / Yu.B. Logvinenko [et al.] // Lab. case. – 1982. – No. 4. – pp. 212–214.

5. Lekomtseva O.I. On the question of clinical significance studies of glycoproteins in recurrent stenotic laryngotracheitis in children / O.I. Lekomtseva // Current problems of theoretical and applied biochemistry. – Izhevsk, 2001. – P. 63–64.

6. Menshchikov V.V. Laboratory methods clinical research / ed. V.V. Menshchikov. – M., Medicine, 1987. – 361 p.

7. Pavlova V.N. Synovial environment of joints / V.N. Pavlova. – M.: Medicine, 1980. – P. 11.

8. Semenova L.K. Studies on age morphology over the past five years and prospects for their development / L.K. Semenova // Archives of anatomy, histology and embryology. – 1986. – No. 11. – P. 80–85.

9. Bitter T. A modified uronic acid carbazole reaction / T. Bitter, H.M. Muir/Anal. Biochem. – 1962. – No. 4. – P. 330–334.

In the literature, synovial fluid (SF) indicators are presented either with outdated data or with data without indicating the method used. In table 1 we present a number of reference values ​​and the results of our own studies of the SF of people who did not have registered articular pathology.

We did not evaluate the reliability of differences in the presented comparison groups using mathematical methods due to the use of different methodological bases in the literature.

It should be noted that our data do not contradict those presented in the literature. However, a number of indicators certainly require methodological clarification.

Materials and research methods

The study material consisted of 31 corpses of suddenly deceased people of both sexes (23 men and 8 women) aged from 22 to 78 years, who did not have articular pathology registered by an expert.

Statistical processing of the obtained results was carried out by the method of variation statistics, used for small samples, with a probability of p equal to 0.05. For each group of observations, the arithmetic mean, the mean square ratio, and the error of the mean were calculated. To study correlation and construct a correlation matrix of heterogeneous features software selects the following rules for calculating correlation coefficients: when calculating the correlation of two quantitative parameters - the Pearson coefficient; when calculating the correlation of ordinal/quantitative and ordinal parameters - Kendall's rank correlation coefficient; when calculating the correlation of two dichotomous characteristics - the Bravais contingency coefficient; when calculating the correlation of quantitative/ordinal and dichotomous characteristics - point-biserial correlation. In order for the program to identify the scale for measuring characteristics, at the stage of selecting the initial data, an interval of characteristics was introduced.

Research results and discussion

We estimate the concentration of total protein (TP) in synovium to be significantly lower than in the literature. The methods most often used to determine OB concentration - biuret and Lowry - differ to varying degrees sensitivity and specificity. Lowry protein determination is more sensitive but less specific than the biuret method. In a number of sources, as well as in our work, the biuret method was used.

Of particular interest is quantitation the main specific component of SF - non-sulfated glycosaminoglycan - hyaluronic acid (HA) (a polymer of disaccharide sequences of acetylated amino sugar and uronic acid). It is known that it is included in the synovium in the form of a hyaluronate-protein complex and is embedded in the surface of the articular cartilage. In the cited sources, the determination of HA began with precipitation with specific precipitants, giving quantification its content by definition of uronic acids. In our data, we present the amount of uronic acids after determination in native synovium, taking into account that glycosaminoglycan precipitants are not specific for their sulfated and non-sulfated forms. We judged the amount of sulfated glycosaminoglycans by the ratio of sulfates to uronic acids. The determination of sialic acids in native synovium characterizes their total content, i.e. the total concentration of free and protein-bound sialic acids in the composition of glycoproteins. Because plasma glycoprotein proteins trigger the cytokine cascade inflammatory reaction after desialylation, with their determination in the synovium, it is natural to expect a connection with clinical characteristics joint diseases. We were unable to compare the data we obtained on the activity of proteolytic enzymes, since in reference sources the indicators of proteolytic activity are given with reference to the substrate protamine sulfate (and in our studies hemoglobin served as the substrate) or without reference to the substrate.

Due to the fact that age-related disorders of the metabolism of articular tissues largely determine the development of degenerative-dystrophic processes in the joints, and women suffer from osteoarthritis almost 2 times more often than men, and in accordance with the objectives set in our work, we assessed the age-related and gender-specific characteristics of the biochemical composition of the fluid. normal human knee joint.

We did not find significant differences in the biochemical composition of SG and women according to the indicators we determined, which is illustrated by the data given in Table. 2.

Table 1

The main chemical components of the synovial fluid of healthy people (in comparison of data from different authors and the results of our own research)

Indicators
Viscosity, mm, 2/s
Total protein, g/l (TB)
Protein, fractions, %, Albumin
α1-globulins
α2-globulins
β-globulins
γ-globulins
Hyaluronic acid, g/l				1,70-2,20
Sulfates, mmol/l,					1.08 ± 0.04
Sulfates/UK
Sialic acid, mmol/				0,16-0,42	0.36 ± 0.01

Notes * - the numbers in bold are those obtained from the authors’ own, after recalculating the dimensions,

** the composition of protein fractions in sources 2 and 4 is given according to K. Kleesiek (1978).

1 - V.N. Pavlova, 1980

2 - Gerasimov, Furtseva, 1986

3 - V.V. Bazarnov, 1999

4 - CITO, 1999

5 - own data

table 2

Biochemical parameters of synovial fluid of the knee joints of men and women

Index	Men (n = 23)	Women (n = 8)
Total protein g/l (TB)
Protein, fractions, % Albumin
α1-globulins
α2-globulins
β-globulins
γ-globulins
Sulfates, mmol/l
Sulfates/UK

Table 3

Values ​​of the correlation between biochemical parameters of synovial fluid of human knee joints with age

Note. Values ​​of the correlation coefficient that are significantly different from zero at the significance level p are highlighted in bold.< 0,05.

Table 4

Concentrations of γ-globulins and sialic acids in the synovial fluid of the knee joint of people of different age groups

Determining the correlation between age and the biochemical composition of the synovium, we calculated the coefficient and significance of the correlation for individual biochemical parameters, as well as the ratio of uronic acids to total protein and sulfates to uronic acids. We took the first ratio as an indicator of the accumulation of proteoglycan metabolic products, and the second as the degree of sulfation of glycosaminoglycans in synovia. The results of calculating correlation indicators are presented in table. 3. The indicators that change most with age are the γ-globulin fraction of protein and sialic acids. For the ratio of sulfates to uronic acids, the correlation coefficient is high at an unreliable level of significance. For other indicators, no significant correlation with age was found. The data obtained allow us to evaluate the correlation between the selected indicators and age as significant. It can be assumed that with age, some accumulation of sialic compounds and γ-globulins occurs in the SF. Obviously, this is a consequence of an increase in the number of glycoproteins, possibly immunoglobulins. One of them biological functions is the utilization of protein breakdown products, which can come from damaged tissues during the involutionary process during aging. We emphasize, however, that there are no significant differences in the level of these compounds in the SF of people of different ages we didn't find it.

To find out standard values indicators that are most associated with age, we assessed the reliability of differences in the concentrations of SA and γ-globulins in different age groups. The distribution of material into groups was carried out according to the scheme recommended by the symposium on age periodization at the institute age physiology USSR Academy of Medical Sciences. With an increase in these indicators, we did not find significant differences in the groups (Table 4).

Thus, the studies did not reveal significant differences in the indicators of the protein spectrum and carbohydrate-containing compounds of the SF of the knee joints of a healthy person based on gender and age, and the closest correlations with a person’s age were found for indicators of γ-globulins and sialic acids.

Based on the presented literature data, it is easy to see that when great variety the methods and techniques of biochemical research used, the information content and diagnostic significance of these studies for practical activities have not been determined.

Bibliographic link

Matveeva E.L., Spirkina E.S., Gasanova A.G. BIOCHEMICAL COMPOSITION OF SYNOVIAL FLUID OF THE KNEE JOINT OF PEOPLE IS NORMAL // Advances in modern natural science. – 2015. – No. 9-1. – pp. 122-125;
URL: http://natural-sciences.ru/ru/article/view?id=35542 (access date: 02/01/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"