Synovial fluid
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Transcript of Synovial fluid
Muhammad Asif ZebLecture Hematology
IPMS-KMU
Objective Physiology and Composition of Synovial
Fluid
Specimen Collection
Laboratory TestingMacroscopic EvaluationChemical ExaminationMicroscopic Examination
Synovial FluidSynovial
syn(like) + ovia (egg)
“Joint Fluid”
Synovial FluidViscous fluid found in
the cavities of movable joints
Synovial membrane Inner membrane of
synovial joints Secretes synovial
fluid into the joint cavity
Contain specialized cells (synoviocytes)
CompositionHyaluronic acid
synthesized by the synovial membraneincrease the viscosity and elasticity of articular
cartilageslubricate the surface between synovium and
cartilage.
Lubricin secreted by synovial cells.
It is chiefly responsible for so called boundary layer lubrication, which reduces friction between opposing surfaces of cartilage.
Major FunctionsReducing friction LubricationLessen shockSupplying oxygen
and nutrients
Synovial Fluid: Specimen Collection
Bulge testThe Bulge test is used to determine if there is an abnormal amount of fluid surrounding a joint
Bulge test of joint for the detection of synovial effusion
Bulge Test
Specimen Collection
Arthrocentesis
Placement of needle in arthrocentesis of (A) elbow and(B) knee joints.
CollectionThree samples are collected.
NoteIf the specimen cannot be examined immediately, fluid should be frozen
and stored at -70°C until examined
Macroscopic Laboratory TestingVolumeColor and ClarityInclusionsViscosityClottingMucin Clot
Laboratory Testing: Macroscopic Volume
Normal up to <3.5 ml of fluid
Can reach up to 25 mlInflammation
Macroscopic Analysis: Color and ClarityColorless to pale yellow and clear
normalRed, brown, or xanthochromic
hemorrhage into the joint Yellow/clear
noninflammatory effusionsYellow/cloudy
inflammationWhite/cloudy/milky
Crystals
Macroscopic Analysis: Inclusions
Rice bodies. Free-floating aggregates of tissue appear
as rice bodies.rheumatoid arthritis (RA) Degenarated synovium enriched with
fibrin
Ochronotic shardsdebris from joint prosthesislook like ground pepper
A =ochronotic shards B =rice bodies
Macroscopic Analysis: Viscosity“Ropes” or “Mucin
Clot Test”Normal = 4-6 cm
When 2-5% acetic acid is added, normal synovial fluid will form a clot surrounded by clear fluid
Macroscopic Analysis: Clotting
Normal synovial fluid: Do not clotClotting of synovial fluid = fibrinogen
1.Damaged synovial membrane 2.Traumatic tap
Macroscopic Analysis: Mucin Clot“Ropes test” Estimation of hyaluronic
acid–protein complex integrity
The adding of acetic acid to normal synovial fluid, which causes clot formation.
Criteria:Compactness of the clotClarity of the supernatant fluid
Mucin TestGood : solid clotFair: soft clotLow: Friable clotPoor: No clot
Microscopic Analysis: Cell CountsTotal leukocyte count
<200 cells/uL
Why is the traditional WBC fluid not used for cell counting?
Because it contains ______________ which is responsible for clotting.
Can clear undiluted fluid be used for counting?
Microscopic Analysis: Cell CountsNeubauer Counting Chamber
Microscopic Analysis: Diff CountIncubate with hyaluronidase Neutrophils : <25% of the differentialLymphocytes: <15%Crystal: None present
Increase neutrophil: septic conditionIncrease cell count with increase lymphocyte:
nonseptic inflammation
Chemical Analysis: ProteinAll proteins found in plasma
Exception: various high–molecular weight proteins which may be present in very small amount
Fibrinogen
beta 2 macroglobulin
alpha 2 macroglobulin
Use common serum protein procedures
Chemical Analysis: Protein (cont.)Normal range <3 g/dl
Increased proteinankylosing spondylitisarthritis Crohn diseaseGoutPsoriasisReiter syndromeulcerative colitis.
Chemical Analysis: GlucoseCompare to serum glucose levels
<10 mg/dL lower than blood glucose
Decreased – joint disorders
Chemical Analysis: Uric AcidNormal - 6 to 8 mg/dL
Increased – gout
May form crystals
Chemical Analysis: Lactic AcidRarely measured in synovial fluid
Can be helpful in diagnosing septic arthritis.
Normal = less than 25 mg/dL
Septic arthritis can show levels up to 1000 mg/dL
Laboratory Testing: Lactate DehydrogenaseElevated in synovial fluidNormal in serum level
Increased in Rheumatoid arthritis
(RA)infectious arthritisgout
Neutrophils increased during the acute phase of these disorders contribute to this increased LD.
Laboratory Testing: Rheumatoid FactorRF is an antibody to immunoglobulins.
Present in rheumatoid arthritis:
Serum – most cases
Synovial fluid - 50%
Rarely elevated only in synovial fluid and not serum
False positives in other chronic inflammatory diseases.
Microscopic Analysis: DifferentialLE cells
Neutrophils that have engulfed a nucleus of a lymphocyte
Tart cellsMonocytes that
have engulfed nuclear material
Microscopic Analysis: DifferentialReiter cells
Vacuolated macrophages with ingested neutrophils
RA cells“Ragocytes”Neutrophils with small,
dark, cytoplasmic granules that consist of precipitated rheumatoid factor
Microscopic Analysis: DifferentialHemosiderin
Seen in Pigmented Villonodular Synovitis
Inclusions within clusters of synovial cells
Rice bodiesMacroscopically
resemble polished riceMicroscopically show
collagen and fibrin
Crystal IdentificationMonosodium urate (MSU)
Calcium pyrophosphate (CPPD)
Crystal Identification
Corticosteroid
Cholesterol
Laboratory Testing: Microbiology Staining
Smears prepared by centrifugation or cytocentrifugation
Saline dilution reduces clustering of cells
Gram’s stain most common
Culture
Set up with positive or negative stain results
Aerobicanaerobic
Classification of Joint Disorders
Classification of Joint DisordersGroup Classification Pathologic Significance
1. Noninflammatory Degenerative joint disorders, osteoarthritis
2. Inflammatory Immunologic Disorders, RA, Scleroderma, Polymyositis, ankylylosing spondylitis, rheumatic fever, Lyme arthritis, Crystal-induced gout, pseudogout
Classification of Joint Disorders3. Septic Microbial Infection
4. Hemorrhagic Traumatic injury, tumors, hemophilia, other
coagulation disorders, anticoagulant overdose
Review of Key PointsSynovial fluid analysis
Is a well-established procedure for evaluation of joint disease.
Determines the presence of arthritisAssists in the classification of joint disordersHelps guides appropriate treatments
Thank you