Synovial Fluid (Part III) Flashcards
Appear as needle-shaped rods 5 to 20 um long
Monosodium urate (MSU)
may be only 1 to 2 um in length or, rarely, may appear as rounded spherolites
Monosodium urate (MSU)
Strongly birefringent
Monosodium urate (MSU)
Color of MSU when oriented parallel to compensator
Yellow
Color of MSU with perpendicular orientation
Blue
A steroid that appears as strongly negative birefringent rod, can be used to prepare a reference slide for the polarizing microscope
Betamethasone
Crystals found in a group conditions collectively known as CPPD crystal deposition disease or pseudogout
Calcium pyrophosphate dihydrate (CPPD)
Crystals that appear rhomboids, rods, or rectangles 1 to 20 um in length.
Calcium pyrophosphate dihydrate (CPPD)
Weakly birefringent with positive elongation
Calcium pyrophosphate dihydrate (CPPD)
Color od CPPD when aligned with the compensator axis
Blue
Many are too small to polarize the light, making them difficult to detect without phase-contrast microscopy
Calcium pyrophosphate dihydrate (CPPD)
CPPD crystals are associated with degenerative arthritis and are seen in arthritides associaed with
Hypomagnesemia
Hemochromatosis
Hyperparathyroidism
Hypothyroidism
Typically too small and nonbirefringent (isotropic) to see with light microscopy unless they are clumped into 1- to 50- um spherical microaggregates
Calcium hydroxyapatite and other BCP crystals
May be used to stain calcium hydroxyapatite and other BCP crystals, and other calcium-containing crystals
Alizarin red S dye
Bipyramidal octahedral “envelopes” with variable birefringence and positive elongation
Calcium oxalate dihydrate
Seen in arthropathy associated with chronic renal dialysis and primary oxalosis, a rare inborn error of metabolism
Calcium oxalate dihydrate
The monohydrate form of this is birefringent but nondescript in shape
Calcium oxalate dihydrate
1 to 20 um spheres with a Maltese cross appearance and positive birefringent under compensated polarized light, they have been implicated as a cause of acute arthritis
Lipid crystals or particels
It is from intraarticular injection that may have an appearance similar to MSU or CPPD crystals and persist up to 1 month following injection
Crystalline corticosteroids
They have blunt, jagged edges without clear crystal structure because they are prepared by grinding up larger crystalline forms
Crystalline corticosteroids
A crystalline corticosteroids that is negatively birefringent
Triamcinolone hexacetonide
Appear as irregular birefringent pates, often with notched corners
Cholesterol crystals
in chronic effusions needle or rhomboid-shaped crystals similar to MSU or CPPD
Cholesterol crystals
Introduced during joint surgery appears as round, strongly birefringent particles 5 to 30 um in diameter, with a central notch and a Maltese cross appearance when polarized
Glove powder (modified cornstarch)
Serum-synovial differential is
> 10 mg/dL
In septic arthritis, the serum-synovial differential ranges from
20 to 60 mg/dL
Cutoff value of serum-synovial difference
75 mg/dL
When the cutoff value of 75 mg/dL is used, the sensitivity of low glucose for detecting an inflammatory joint disease is only ____ and the specificity is _____
sensitivity: 20%
specificity: 84%
Reference intervals for Synovial Fluid and Plasma:
Total protein
SF: 1-3 g/dL
Plasma: 6-8 g/dL
Reference intervals for Synovial Fluid and Plasma:
Albumin
SF: 55%-70%
Plasma: 50%-65%
Reference intervals for Synovial Fluid and Plasma:
a1-Globulin
SF: 6%-8%
Plasma: 3%-5%
Reference intervals for Synovial Fluid and Plasma:
a2-Globulin
SF: 5%-7%
Plasma: 7%-13%
Reference intervals for Synovial Fluid and Plasma:
B-Globulin
SF: 8%-10%
Plasma: 8%-14%
Reference intervals for Synovial Fluid and Plasma:
y-Globulin
SF: 10-14%
Plasma: 12%-22%
Reference intervals for Synovial Fluid and Plasma:
Hyaluronic acid
SF: 0.3-0.4 mg/dL
Reference intervals for Synovial Fluid and Plasma:
Glucose
SF: 70-110 mg/dL
Plasma: 70-110 mg/dL
Reference intervals for Synovial Fluid and Plasma:
Uric acid
SF: 2-8 mg/dL
Plasma: 2-8 mg/dL
Reference intervals for Synovial Fluid and Plasma:
Lactate
SF: 9-29 mg/dL
Plasma: 9-29 mg/dL
Numerous enzymes that has been studies in SF
lactate dehydrogenase
aspartate aminotransferase
adenosine deaminase
acid and alkaline phosphate
lysozyme
Lactate dehydrogenase is elevated in
RA
gout
failed arthroplasties
infectious arthritis
When compared with nonseptic monoarticular arthritis, SF _____ levels are usually increased in patients with septic arthritis
Lactic acid
Measurement of this in SF appears to be a useful method for rapid diagnosis of bacterial synovitis
D-lactate levels
Increased SF uric acid levels support a diagnosis of
gout
Synovial fluid lipid abnormalities include
(1) rare cholesterol-rich pseudochylous effusions typically associated with chronic RA
(2) lipid droplets, usually the result of trauma
(3) extreme rare chylous effusions seen in association with RA, SLE, filariasis, pancreatitis, and trauma
3 Immunologic studies
Rheumatoid factor (RF)
Antinuclear antibodies (ANAs)
Complement
Immunologic study where found in the SF of about 60% of RA patients, usually a titer equal to or slightly lower than the serum titer
Rheumatoid factor (RF)
Immunologic study found in the SF of about 70% of patients with SLE and 20% of patients with RA
Antinuclear antibodies (ANAs)
Immunologic study normally about 10% of serum levels, increase to 40% to 70% of serum activity with inflammation, proportional to the increase in protein exudation
Complement
Complement consumption in SLE, and RA in particular, results in levels _____ of serum complement
<30%
