Synovial Fluid (Part II) Flashcards
Under Microscopic Examination
total cell count
differential leukocyte count
crystal examination
Total leukocyte counts should be performed as soon as ______ following arthrocentesis
1 hour
Leukocyte counts over 50,000/uL require dilution which should be done with ______ to avoid mucin clot formation and cell clumping
saline, not acetic acid
Their use risks clogging the machine aperture or obtaining spuriously high cell counts from non-WBC particles (crystals, fat globules)
Flow cell-based automated cell counters
Pretreatment of highly viscous SF samples with ______ improves automated cell counting using instruments
hyraluronidase
Leukocyte counts greater than 10,000/uL, and often gretaer than 50,000 are characteristic of
crystal-induced arthritis (e.g., gout, pseudogout)
chronic inflammatory arthritis (RA, SLE, ankylosing spondylitis)
septic arthritis
These clinical conditions usually have total WBC counts less than 10,000/uL
Osteoarthritis
Osteochondritis dissecans
trauma
synovioma
If a large number of RBCs interferes with leukocyte count, they may be lysed with dilution with
0.3 normal saline or 1% saponin in saline
The upper reference level for SF leukocyte
150 to 200/uL
Preparation preferred over smears from centrifuged SF because the cell morphology is significantly better preserved
Cytospin preparations
Treatment with this may be necessary to produce thin smears in viscous specimens
Hyaluronidase
Used effectively to produce good-quality preparations of SF for microscopic examination
Liquid-based thin-layer processing instruments
Normally account 20% of SF leukocyte
Neutrophils
Neutrophils generally exceed 50% in
urate gout
pseudogout
RA
Neutrophils most often exceed 75% in
acute bacterial arthritis
In differential leukocyte cell count, when 75% of the neutrophils are used as a cutoff, the sensitivity for an inflammatory process is about _____ and the specificity is _____
sensitivity: 75%
specificity: 92%
Neutrophils may frequently exhibit degenerative changes and may contain ______ that is thought to consist of immune complexes
bacteria
crystals
lipid droplets
vacuoles
dark blue to black granular inclusions
The presence of ____ in patients with RA may indicate a poorer outcome
Ragocytes
Present in patients with lupus arthritis
Lupus erythematosus (LE) cells
Most often neutrophils that have phagocytosed the nuclei of degenerating cells
Lupus erythematosus (LE) cells
normally constituting about 15% of SF cells
Lymphocytes
Leukocyte prominent in early RA and other autoimmune disorders, as well as in chronic infections
Lymphocytes
The most common cells present in normal SF
Monocytes and Macrophages
Accounting for approximately 65% of the cell count
Monocytes and Macrophages
May be self-limited in viral arthritis or serum sickness, or more chronic in SLE or undifferentiated connective tissue disorders
Monocytosis
Originally believed to be specific for Reiter syndrome, are macrophages containing degenerating neutrophils
Reiter cells
Defined as more than 2% of the leukocyte count
Eosinophils
Eosinophils has been reported in the following conditions:
Lyme disease
RA
Rheumatic fever
Metastatic carcinoma
Parasitic infection
Chronic urticaria
Angioedema
Following Arthtography and irridiation
Allergy to dye
Arthrography
Leukocyte that has no pathologic significance
Synovial cells (synoviocytes)
They appear similar to mesothelial cells and may be difficult to distinguish from monocytes and macrophages
Synovial cells (Synoviocytes)
Diseases associated with Lipid bodies
Trauma
Aseptic necrosis
RA
These droplets often form Maltese Cross under polarized light, and can be associated with leukocyte response, and may cause spurious elevations of the automated WBC count
Lipid bodies
This lead to acute inflammation with increased WBC cunts and a neutrophil-predominant infiltrate
Crystals in SF
refers to the process of crystal deposition in articular tissue
Gout
An inflammatory response to crystal depositions referred to as
gouty arthritis
Most common types of endogenous crystals responsible for gouty arthritis:
Monosodium urate monohydrate (Urate gout)
Calcium pyrophosphate dihydrate (Pyrophosphate gout, chondrocalcinosis, or pseudogout)
Apatite and other basic calcium phosphates (BCP)
Calcium oxalate (oxalate gout)
Lipids (lipid gout)
It is placed directly above the light source of polarizing microscope
Polarizer
another polarizer filter that is placed between the specimen slide and the microscope oculars, oriented 90 degrees from the polarizer to produce a dark background
Analyzer
Placed between the polarizer and analyzer, usually oriented 45 degrees (halfway) between the planes of two polarizing filters
Compensator
Initial examination of crystal examination should be performed on a
wet preparation using polarized light
Enhances crystal detection
Phase-contrast microscopy
Most crystals are scanned with
10x objective
Crystals are evaluated with at least ______ concentrating especially on cellular areas
40x objective
Complete examination of crystals requires
100x oil immersion
Sensitivity and Specificity of polarized microscopy for crystals for monosodium urate
Sensitivity: 78%
Specificity: 79%
Sensitivity and Specificity of polarized microscopy for crystals for calcium pyrophosphate dihydrate
Sensitivity: 12%
Specificity: 67%
reliable alternative to polarized microscopy
Diff-Quick staining method
Specificity, sensitivity, and accuracy of Diff-Quick staining method
Specificity: 87.5%
Sensitivity: 94.4%
Accuracy: 91.9%
Overall positive predictive value for Diff-Quick staining method
92.7%
Overall negative predictive value for Diff-Quick staining method
90.3%
