synovial fluid analysis.pptx synovial fluid analysis

Synovial fluid analysis is a diagnostic test that examines the fluid surrounding a joint to help identify the cause of joint pain, swelling, or stiffness, such as arthritis, gout, or infection. The analysis involves checking the fluid's appearance, performing chemical tests to measure levels of glucose, protein, and uric acid, and using a microscope to look for crystals, bacteria, or abnormal blood cells.

1. SYNOVIAL FLUID ANALYSIS

2. Moderators Presented by: Sumanta Khan (PG) Department of Orthopaedics Kakatiya Medical College, Warangal DR.K. RAMKUMAR REDDY(HOD AND PROF) DR RAM MOHAN (ASSOCIATE PROFESSOR) DR. D PRASAD REDDY (ASSISTANT PROF) DR.M PRAKASH (ASSISTANT PROF) DR. SANTHOSH SRIKANTH (ASSISTANT PROF) DR. SHWETHA MADHURI (ASSISTANT PROF)

3. Introduction Synovial fluid analysis can differentiate between noninflammatory , inflammatory and traumatic conditions. Systematic examination includes macroscopic and microscopic, and biochemical analysis. Microscopic examination: Differential white blood cell count, total white and red blood cells, evaluation for crystals is done. Physical characteristics: The fluid volume, color, clarity, viscosity of the joint fluid is seen. Microbiological studies: Cultures are done and Gram’s and AFB stains are performed. Serological studies: Glucose, proteins, lactate dehydrogenase.

4. Collection of specimen Arthrocentesis is done avoiding contamination. The syringe is rinsed with sodium heparin (25 U/mL), EDTA and oxalate are crystalline in the dry state, and are avoided so as to prevent any artefacts while checking for crystals. For cytological examination 2mg potassium oxalate per mL of synovial fluid is added. Culture for pyogenic bacteria and mycobacteria, Romanowsky stains and wet preparation for analysis for crystals must be performed.

5. Gross examination Clarity : Normally transparent. Rise in proteins and/or cells make it cloudy. Depending on appearance, flecks can be rice bodies as in tuberculosis, rheumatoid arthritis. In ochronosis , flecks resemble ground pepper or wear particles from prosthesis.

6. Color : Normally it is clear to a light yellow. Xanthochromia is seen in long standing hemorrhage and pigmented villonodular synovitis. Color may be opaque or cloudy white in inflammations and in chronic arthritis or lymphatic obstruction it is chylous .

7. Viscosity : Hyaluronate gives it high viscosity. This is tested by suspending a drop of fluid from a needle tip (syringe drip test) or between two glass slides, a 3–5 cm long “string” is formed. Increased water content leads to a shorter string as in inflammation or sudden edema. The viscosity may also be tested with Hess viscosimeter .

8. Clot formation Glacial acetic acid is used to test for mucin clot formation. A tight clump formation is seen when glacial acetic acid is added to synovial fluid due to aggregation of mucin . The clump is firm, ropy and does not disintegrate on vigorous shaking. In mild inflammation, the clump is soft and friable. In advanced inflammation, there is cloudy flocculent precipitate formation. Spontaneous clot formation is seen in hemarthrosis .

9. Synovial fluid gross examination. Color of fluid varies with pathology. (A) Normal straw colored synovial fluid. (B) Fluid color deepens to yellowish in degenerative arthropathy . (C) Little turbidity is added in crystal arthropathy . (D) Finally pus like thicker fluid with greater turbidity is seen in septic arthritis

10. Cell count The typical WBC count of normal synovial fluid is less than 180 nucleated cells/ cu.mm Normal DLC reads - N 0- 25; L 0-78; M 0-71 ; Histiocytes 0-26; Synoviocytes 0-12 Red cell counts help to identify hemorrhagic effusion. Cell counts: <2000 – non inflammatory 2000- 50,000 -- inflammatory >50000 – infection

11. Light microscopy Erythrophagocytosis , hemosiderin pigment and hematoidin crystal (intracellular or extracellular golden yellow refractile ) are found in intra-articular hemorrhage. Iron laden chondrocytes suggest hemochromatosis. Ragocytes are granulocytes that have engulfed immune complexes, is associated with active RA, and their presence may indicate an unfavorable prognosis in this disease Reiter’s cells are macrophages containing one or more phagocytized neutrophils seen in various inflammatory conditions.

12. Marrow fragments in synovial fluid indicate intra-articular fracture Platelets may be found in rheumatoid arthritis. Lipid-laden macrophages (Oil red O or Sudan black B fat stain) may be seen in traumatic arthritis and chylous arthritis. Lipid may show “Maltese cross” birefringence under polarized light. Cartilage cells may be seen following trauma or degenerative arthritis. Yellow chondrocytes are seen in ochronosis . Lupus erythromatosus cells are neutrophils that contain a phagocytized nucleus and can be seen in systemic lupus erythromatosus (SLE) and rheumatoid arthritis.

13. Examination of Crystals Crystals are examined as a wet preparation under high power (400 or 1,000×) in a polarized light. Monosodium urate crystals (intracellular or extracellular) Needle-shaped, 5–25 mm long and Strongly negatively birefringent. If polarized light is not available then MSU crystals can be recognized by their size and color in Romanowsky stain. Calcium pyrophosphate dihydrate (CPPD) crystals (intracellular or extracellular): Rod to rhomboidal shaped, 1–20 mm in length and up to 4 mm in width, Weakly positive birefringent.

14. Urate  crystals in the tophus from a patient with gouty arthritis. Crystals are negatively birefringent and needle shaped intra-cellular  urate  crystal as seen on Wright stain Calcium pyrophosphate crystals in the synovial fluid from a patient with  pseudogout . Crystals are positively birefringent and rhomboid shaped

15. Steroid crystals seen following intra-articular steroid injection usually extracellular (can be intracellular in neutrophils): Mimic MSU crystals, 10–20 mm in length, rectangular to needle shaped Polarized light: Negatively birefringent. Calcium oxalate crystals are associated with primary oxalosis and chronic renal failure on dialysis: Pyramidal, 1–2 mm in size, Polarized light: Positively birefringent. Cholesterol crystals (extracellular) seen with chylous effusion: Large flat rhomboidal plates with notched corners, Polarized light: Strongly positively birefringent

16. Basic calcium phosphate crystals Deposits of hydroxyapatite or basic calcium phosphate are present the shoulder area and implicated in Milwaukee shoulder. Generally nonbirefringent, it is not possible to detect them by polarized microscopy. A rapid method is to stain the fluid with alizarin red S stain and look for clumps of crystals under routine light microscopy

17. Chemical analysis Glucose : Synovial fluid and plasma specimens are to be collected at the same time. Glucose difference between synovial fluid and plasma is important rather than absolute values. Estimated using Somogyi -Nelson method. Normally, there is a glucose difference of less than 10 mg/dL between serum and joint fluid. Low synovial fluid glucose can be used to differentiate infection from inflammatory effusion. With increasing inflammation, glucose levels in joint fluids fall. Infection is to be considered when synovial fluid glucose is less than 20 mg/dL and difference exceeds 50%.

18. Lactate : Synovial fluid lactate rises in infections. Protein : The utility is very limited and does not differentiate between transudate and exudate. An increase in protein concentration above 2.5 g/dL is not normal and if more than 4.5 g/dL, is suggestive of inflammation.

19. Microbiological and Immunological Examination Gram’s stain is a rapid test to identify and confirm the pathogen in septic arthritis and immediately indicates the antibiotic sensitivity of organism. Latex agglutination is used for rapid analysis of fungal and bacterial antigens. It may be negative in patients on antimicrobial therapy. Most immunological tests pertain to rheumatoid arthritis. The finding of rheumatoid factor in synovial fluid is specific to rheumatoid arthritis

20. Synovial fluid culture and pcr Gold standard for diagnosing septic arthritis is still bacteriologic culture, which has a sensitivity of 75% to 95% and a specificity of 90% in cases of nongonococcal septic arthritis. use of blood culture bottles further increases the yield of positive synovial cultures. Bacteriologic cultures are the only studies that provide a guide for specific anti-microbial therapy. Because the sensitivity of bacteriologic cultures declines dramatically after antibiotic therapy is started, it is important to perform arthrocentesis before any antibiotics are administered.

21. Polymerase chain reaction ( PCR ) has a high degree of sensitivity and specificity for the detection of microorganisms in synovial fluid and tissue, even in individuals who are culture negative. Most bacteria can be detected on the basis of amplifying specific sequences in their ribosomal RNA (16S rRNA ). PCR is now the procedure of choice for diagnosing gonococcal arthritis and is a highly sensitive and specific method of detecting tuberculous arthritis, although analysis of synovial tissue is better than analysis of synovial fluid for making this diagnosis. PCR is also a method of verifying the successful elimination of the offending organism in cases of septic arthritis Synovial fluid pcr

22. Apperance Viscosity Cell count (/cu. mm) %PMN Crystals Cultures normal Transparent High <200 <10% - Negative osteoarthritis Transparent High 200- 2000 <10% Occasional calcium pyrophosphate And hydroxyapatite crystals Negative Rheumatoid arthritis Translucent Low 2000-50,000 Variable - Negative Psoriatic Arthritis Translucent Low 2000-50,000 Variable - Negative Reactive arthritis Translucent Low 2000-50,000 Variable - Negative Bacterial arthritis Cloudy Variable >50,000 >90% _ Positive

23. Apperance Viscosity Cell count (/cu. mm) %PMN Crystals Cultures normal Transparent High <200 <10% - Negative Gout Translucent to cloudy Low 200-50,000 >90% needle-shaped, negatively birefringent monosodium  urate  monohydrate crystals Negative Pseudogout Translucent to cloudy Low 200-50,000 >90% Rhomboid, positively birefringent calcium pyrophosphate crystals Negative PVNS Hemorrhagic or brown Low _ _ _ Negative Haemarthrosis Hemorrhagic Low _ _ _ Negative

24. Algorithm for synovial fluid analysis

25. Conclusion Analysis of synovial fluid provides valuable diagnostic information in specific clinical settings. In cases in which septic or crystal-induced arthritis is suspected, as in acute monoarthritis , synovial fluid analysis is critical for the diagnosis. In cases of undiagnosed chronic monoarthritis , synovial biopsy may provide definitive evidence of conditions such as TB, sarcoidosis, and pigmented villonodular synovitis. Research protocols are currently exploring the utility of synovial fluid analysis and synovial biopsy in predicting response to anti-rheumatic therapies.

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