How can we help?

You can also find more resources in our Help Center.

35 terms

Synovial Fluid

STUDY
PLAY
Description
-viscous and in all movable joints
Function
reduce friction between bones
transport O2 and nutrients
lessen shocks
Location
between articular cartilage on bones
Formation
ultrafiltrate of plasma
chemical components are in similar concentration to plasma
hyaluronic acid secreted by lining cells to give fluid viscosity
Volume
minimal (knee has 3.5 ml)
increased in diseased joints
Analysis
Arthrocentesis- to remove fluid
-aids in diag of arthritis and other pathologies: pain and stiffness due to damage, infections, inflammation, metabolic disorders, trauma, age, stress
Normal
-<3.5 ml
-pale clear/yellow
-forms viscous string 4-6 cm
-<2000 RBC/ul
-<200 NUC/ul
-<25% neuts
-<75% lymphs
-<60-70% macro.mono
-no crystal
-<10 mg/dl lower glucose than blood
-<250 mg/dl lactate
-<3 g/dl total protein
-uric acid equal to PB
Groups of joint disorders
-noninflam: degenerative joint disorders, osteoarthritis
-inflam:RA, LE, pseudogout
-inflam (crystals): gout, CPPD
-septic: microbial
-hemorrhagic: trauma, coag deficiencies, tumors, anticoagulant OD
Noninflam: degenerative joint disorders
-yellow/clear.
-NUCs<1000
-increased macrophages and lymphs (<30% neut)
-no crystals
-no rbcs
-normal glucose, protein, viscosity, culture
-osteoarthritis, traumatic arthritis, sickle cells disease
Inflam
-yellow/cloudy
-NUCs 2000-75000/ul (neuts >50%)
-no crystals, RBCs, bact
-decreased glucose and viscosity
-increased protein
-RA, SLE, rheumatic fever
Inflam: crystal induced
-yellow/cloudy
-NUCs up to 100,000/ul
-<70% neuts
-decreased glucose and viscosity
-increased protein and uric acid
-gout, pseudogout
Infectious
-yellow to green, cloudy
-NUCs 50,000-100,000/ul (>75% neut)
-no crystals
-RBCs present
-glucose and viscosity decreased
-protein increased
-bacteria or fungal
Hemorrhagic
-red/brown, xanthochromic
-many RBCs
-NUCs 50-10,000 (neuts predomin)
normal glucose
-increased protein
-decreased viscosity
-traumatic arthritis, anticoag therapy
Increased turbidity
-increased WBC
-Cellular debris
-fibrin
Viscosity
infla joint disease: depolymerizes complex causing watery fluid (arthritis)
-not a reliable test
-rated good, fair, poor.
Cell counts
-count may include lining cells
-hyaluronidase to break down hyaluronic acid
-do not use acetic acid for count- causes mucin clots
-norm <200
Abnormal Diff
-↑ neuts= sepsis
-↑ lymphs= non septic inflam
-↑eos= allergic rxn, rheumatic fever, parasites, metastatic carcinoma
-LE cells
-Reiter cells (vacuolated macros with ingested neuts)
-ragocytes (RA cells)- neuts with small dark granules of rheumatoid factor
Synovial lining cell
-covers non-articular surfaces of joint cavity
-round to oval shape
-dense chromatin, abundant cyto
-no significance
LE cell
-10% of LE patients
-can be in RA too
-hematoxalyn body- smooth chromatin completely ingested by neutrophil (never mono)
Lipophages
-lipid laden macros
-long standing RA, trauma, aseptic necrosis
Reiter Cells
-vacuolated macros with phagocytosed nuclear material
-indicates resolution of acute phase of inflam, not specific for reiters syndrome
-one or more neuts may be in varying phases of degeneratiion present in cytoplasm
Crystal evaluation
-need to ID crystals to treat
-factors for crystal deposition: increasing age, familial predisposition, joint damage, post medicine injection
Crystal examination
-perform soon after collection
-intracellular and extracellular
-observed on counting chamber, polarized and compensated light
-determine crystals birefrigence properties
-primarily to detect uric acid and CPPD
Monosodium urate (uric acid)
-diag of gout: disorder of purine metabolism, variable and raised blood levels, severe recurrent acute arthritis of sudden onset
-crystals in connective tissues and cartilage
-strong birefrigence: rotate light and appear very brigh against dark background
-intra (90% acute) and extracellular, needle shaped, 2-20 um
-yellow parallel to compensator, blue perpendicular
Calcium pyrophosphate (CPPD)
-pseudogout or degenerative arthritis (calcium leached from bones in degeneration), metabolic disorders with increased calcium
-weak birefringence: appear dim
-acute-intracell, chronic extracell
-pleomorphic: rhombohedral, plate-like, rod-like
-yellow perpendicular to polarized light, blue parallel
Cholesterol
-flat, transparent and plate-like with notches.
-occurs in turbid thick specimen
-extracell
-rare
- in RA of long duration
Corticosteroid crystals
- 1 month post injection
Polyethylene Crystals
artifact from joint replacement
Starch powder crystals
contamination from gloves
maltese cross under polarized light
Hematoidin crystals
post joint bleed
Chemistry tests
-approx same as serum
Glucose
marked decreased- inflam or sepsis (<20)
compare to serum
Lactic acid
dif inflam or septic
>250 mg/dl in septic and sometimes RA
total protein
norm: <3 mg/dl (1/3 serum)
increased in inflam and hemorrhagic
mircobiology
infection secondary to inflam
bact most common, but can be fungal, TB, viral
gram stain and culture