Synovial Fluid Synovial Fluid ExaminationExamination

Presented By:Presented By:

Nasir NazeerNasir Nazeer

IntroductionIntroduction

Synovial fluid is a viscous, non-Newtonian fluid found in the cavities Synovial fluid is a viscous, non-Newtonian fluid found in the cavities of synovial joints.of synovial joints. With its yolk-like consistency, the principal role of synovial fluid is to With its yolk-like consistency, the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during reduce friction between the articular cartilage of synovial joints during movement.movement.The inner membrane of synovial joints is called the synovial The inner membrane of synovial joints is called the synovial membrane and secretes synovial fluid into the joint cavitymembrane and secretes synovial fluid into the joint cavityThe fluid contains hyaluronic acid secreted by fibroblast-like cells in The fluid contains hyaluronic acid secreted by fibroblast-like cells in the synovial membrane and interstitial fluid filtered from the blood the synovial membrane and interstitial fluid filtered from the blood plasma. plasma. This fluid forms a thin layer (roughly 50 μm) at the surface of cartilage This fluid forms a thin layer (roughly 50 μm) at the surface of cartilage and also seeps into micro-cavities and irregularities in the articular and also seeps into micro-cavities and irregularities in the articular cartilage surface, filling all empty space.cartilage surface, filling all empty space.During movement, the synovial fluid held in the cartilage is squeezed During movement, the synovial fluid held in the cartilage is squeezed out mechanically to maintain a layer of fluid on the cartilage surface out mechanically to maintain a layer of fluid on the cartilage surface (so-called (so-called weeping lubricationweeping lubrication). ).

Functions of Synovial FluidFunctions of Synovial Fluid

Reduction of friction - synovial fluid lubricates the Reduction of friction - synovial fluid lubricates the articulating joints.articulating joints.Shock absorption - as a dilatant fluid, synovial Shock absorption - as a dilatant fluid, synovial fluid is characterized by the rare quality of fluid is characterized by the rare quality of becoming more viscous under applied pressure; becoming more viscous under applied pressure; the synovial fluid in diarthrotic joints becomes the synovial fluid in diarthrotic joints becomes thick the moment shear is applied in order to thick the moment shear is applied in order to protect the joint and subsequently, thins to protect the joint and subsequently, thins to normal viscosity instantaneously to resume its normal viscosity instantaneously to resume its lubricating function between shocks.lubricating function between shocks.Nutrient and waste transportation - the fluid Nutrient and waste transportation - the fluid supplies oxygen and nutrients and removes supplies oxygen and nutrients and removes carbon dioxide and metabolic wastes from carbon dioxide and metabolic wastes from the chondrocytes within the surrounding cartilage.the chondrocytes within the surrounding cartilage.

Reasons for Synovial Fluid Reasons for Synovial Fluid ExaminationExamination

Joint aspiration may be performed to diagnose and assist in the Joint aspiration may be performed to diagnose and assist in the treatment of joint disorders and/or problems. By analyzing the fluid treatment of joint disorders and/or problems. By analyzing the fluid obtained during the procedure, the following conditions may be obtained during the procedure, the following conditions may be determined:determined:

GoutGout Various types of arthritisVarious types of arthritis Joint infectionJoint infection

Joint aspiration can also be performed to remove a large Joint aspiration can also be performed to remove a large collection of fluid around a joint. Sometimes bursitis (inflammation of collection of fluid around a joint. Sometimes bursitis (inflammation of the bursa) causes fluid to collect in a joint. Removing the fluid will the bursa) causes fluid to collect in a joint. Removing the fluid will decrease the pressure, relieve pain, and improve movement of the decrease the pressure, relieve pain, and improve movement of the joint. Sometimes, a medication is injected into the joint following joint. Sometimes, a medication is injected into the joint following removal of the fluid to help treat tendonitis or bursitis.removal of the fluid to help treat tendonitis or bursitis.

Risks involved in Synovial fluid Risks involved in Synovial fluid AspirationAspiration

As with any surgical procedure, As with any surgical procedure, complications can occur. Some possible complications can occur. Some possible complications may include, but are not complications may include, but are not limited to, the following:limited to, the following: Discomfort at the aspiration siteDiscomfort at the aspiration site Bruising at the aspiration siteBruising at the aspiration site Swelling at the aspiration siteSwelling at the aspiration site Infection at the aspiration siteInfection at the aspiration site

Precautions before aspiring Precautions before aspiring Synovial FluidSynovial Fluid

Doctor should explain the procedure to the patients and offer the Doctor should explain the procedure to the patients and offer the opportunity to ask any questions that they might have about the opportunity to ask any questions that they might have about the procedure. Laboratory staff should also guide the patient about the procedure. Laboratory staff should also guide the patient about the test and procedure of drawing the sample.test and procedure of drawing the sample.Patients are asked to sign a consent form that gives permission to do Patients are asked to sign a consent form that gives permission to do the procedure. the procedure. The laboratory staff should notify if patient is sensitive to or are The laboratory staff should notify if patient is sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local allergic to any medications, latex, tape, and anesthetic agents (local and general).and general).The laboratory staff should also notify all medications (prescribed and The laboratory staff should also notify all medications (prescribed and over-the-counter) and herbal supplements that the patients are over-the-counter) and herbal supplements that the patients are taking.taking.The laboratory staff should also note if the patient have a history of The laboratory staff should also note if the patient have a history of bleeding disorders or if patient is taking any anticoagulant (blood-bleeding disorders or if patient is taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood thinning) medications, aspirin, or other medications that affect blood clotting. It is necessary to stop these medications prior to the clotting. It is necessary to stop these medications prior to the procedure.procedure.Generally, no prior preparation, such as fasting or sedation is Generally, no prior preparation, such as fasting or sedation is required. required.

During Synovial Fluid AspirationDuring Synovial Fluid Aspiration

A joint aspiration may be performed on an outpatient basis. Procedures A joint aspiration may be performed on an outpatient basis. Procedures may vary depending on patient’s condition. Generally, a joint may vary depending on patient’s condition. Generally, a joint aspiration procedure follows this processaspiration procedure follows this process

Patient should be positioned so that the doctor/technician can easily Patient should be positioned so that the doctor/technician can easily reach the joint that is to be aspirated.reach the joint that is to be aspirated.

The skin over the joint aspiration site should be cleansed with an The skin over the joint aspiration site should be cleansed with an antiseptic solution.antiseptic solution.

If a local anesthetic is used, patient will feel a needle stick when the If a local anesthetic is used, patient will feel a needle stick when the anesthetic is injected. This may cause a brief stinging sensation.anesthetic is injected. This may cause a brief stinging sensation.

The doctor/technician will insert the needle through the skin into the joint. The doctor/technician will insert the needle through the skin into the joint. Patient may feel some discomfort or pressure.Patient may feel some discomfort or pressure.

The doctor/technician will remove the fluid by drawing it into a syringe The doctor/technician will remove the fluid by drawing it into a syringe that is attached to the needle.that is attached to the needle.

The needle will be removed and a sterile bandage or dressing will be The needle will be removed and a sterile bandage or dressing will be applied.applied.

The fluid sample is sent to the lab for examination.The fluid sample is sent to the lab for examination.

After Synovial Fluid AspirationAfter Synovial Fluid Aspiration

Once sample is drawn, it is important for the patient to Once sample is drawn, it is important for the patient to keep the joint aspiration site clean and dry.keep the joint aspiration site clean and dry.The aspiration site may be tender or sore for a few days The aspiration site may be tender or sore for a few days after the joint aspiration procedure.after the joint aspiration procedure.Take a pain reliever for soreness as recommended by Take a pain reliever for soreness as recommended by the doctor. Aspirin or certain other pain medications may the doctor. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only increase the chance of bleeding. Be sure to take only recommended medications.recommended medications.The patient should be guided to report to the doctor in The patient should be guided to report to the doctor in any of the following conditions after fluid aspiration any of the following conditions after fluid aspiration procedure:procedure:

FeverFever Redness, swelling, bleeding, or other drainage from the Redness, swelling, bleeding, or other drainage from the

aspiration siteaspiration site Increased pain around the aspiration siteIncreased pain around the aspiration site

Specimen handling and Specimen handling and collectioncollection

Synovial fluid is present in all joints but usually it is Synovial fluid is present in all joints but usually it is collected from the knee joint. Normal amount of collected from the knee joint. Normal amount of fluid contained in the knee cavity is less than fluid contained in the knee cavity is less than 3.5mL; however this amount increases in joint 3.5mL; however this amount increases in joint disorders. The sample collected is dependent disorders. The sample collected is dependent upon amount of fluid build up in the joints. upon amount of fluid build up in the joints. Normally samples are collected in three tubes.Normally samples are collected in three tubes. EDTA tubes – for Cell count and differentialsEDTA tubes – for Cell count and differentials Heparinized tubes – Chemical and Immunologic testsHeparinized tubes – Chemical and Immunologic tests Sterile tubes – Crystal examination and Microbiological Sterile tubes – Crystal examination and Microbiological

testing testing

Laboratory Tests of Synovial FluidLaboratory Tests of Synovial Fluid

Following are the tests performed of Synovial joints fluid.Following are the tests performed of Synovial joints fluid.Gross examination for color and clarityGross examination for color and clarityAppearance Appearance

Clear and light yellow – NormalClear and light yellow – Normal Turbid or cloudy – elevated cell count, crystals, cartilage debrisTurbid or cloudy – elevated cell count, crystals, cartilage debris BloodyBloody

Hemorrhagic fluid – homogenously bloodyHemorrhagic fluid – homogenously bloodyTraumatic aspirate – streaks of bloodTraumatic aspirate – streaks of blood

Color – varies based on bacterial infection, cell or crystal presenceColor – varies based on bacterial infection, cell or crystal presenceLeukocyte count and differential (Place sample under a microscope, Leukocyte count and differential (Place sample under a microscope, count the number of red and white blood cells, and then looks for count the number of red and white blood cells, and then looks for crystals (in the case of gout or bacteria)crystals (in the case of gout or bacteria)Measure glucose, proteins, uric acid, and lactic dehydrogenase Measure glucose, proteins, uric acid, and lactic dehydrogenase (LDH)(LDH)Culture the fluid to see if any bacteria growsCulture the fluid to see if any bacteria grows

Classification of Synovial FluidClassification of Synovial Fluid

NormalNon-inflammatory

Inflammatory

Septic Hemorrhagic

Volume (ml)

<3.5 >3.5 >3.5 >3.5 >3.5

Viscosity High High Low Mixed Low

Clarity Clear Clear Cloudy Opaque Mixed

ColorColorless/straw

Straw/yellow Yellow Mixed Red

WBC/mm3 <200 <2,0005,000-75,000

>50,000Similar to blood level

Polys (% <25 <25 50-70 >70Similar to blood level

Gram stain Negative Negative NegativeOften positive

Negative