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crystals in synovial fluid

Indications: 1) monosodium urate crystals a) 3-20 um long b) within neutrophils, distending neutrophil cytoplasm c) strongly negatively birefringent crystals d) with 1st order red compensator, crystals are yellow when parallel to the orienting line & blue when perpendicular e) associated clinical disorders: 1] gout 2] septic arthritis 2) calcium pyrophosphate dihydrate (CPPD) crystals a) plate-like, rhomboid, rod or needle-shaped b) weakly positively birefringent c) with 1st order red compensator, crystals are blue when parallel to the orienting line & yellow when perpendicular d) associated clinical disorders: 1] pseudogout 2] hypomagnesemia 3] hemochromatosis 4] hyperparathyroidism 5] hypothyroidism 3) hydroxyapatite crystals a) small, needle-shaped crystals < 1 um long & 7.5-25 nm in diameter b) too small to be seen by light microscopy c) electron microscopy needed for identification d) aggregated lumps 1] may be birefringent 2] staining with alizarin red S [3] e) not important for diagnosis, prognosis or guidance in treatment 4) calcium oxalate dihydrate crystals a) bipyramdal envelopes, 5-30 um in diameter b) variable birefringence with elongation c) associated clinical disorders: 1] arthropathies associated with renal dialysis 2] primary oxalosis (rare inborn error of metabolism) 5) lipid crystals a) spheres 1-20 um in diameter b) maltese cross appearance with positive birefringence under compenstated polarized light c) associated clinical disorders: acute arthritis 6) cholesterol crystals a) large, extremely bright, square or rectangular plate-like crystals often with notch in corner b) in rare circumstances, crystals may be rod or needle-shaped & negatively birefringent c) generally not phagocytized by neutrophils 7) corticosteroid crystals a) may be positively or negatively birefringent b) pleomorphic c) generally from intra-articular steroid injections 8) lithium heparin crystals (positively birefringent) 9) starch or glove powder a) round, strongly birefringent, 5-30 um in diameter b) may appear as maltese cross under polarized light c) may be introduced during joint surgery 10) other crystals or particulate matter found in synovial fluid a) immunoglobulins 1] monoclonal gammopathy 2] cryoglobulinemia b) Charcot-Leyden crystals c) amyloid fragments d) cartilage fragments e) collagen fibrils f) fibrin strands g) hematoidin crystals from previous hemorrhage h) crystals from anticoagulants i) nail polish j) prosthetic fragments k) dust particles

Related

synovial fluid

Specific

calcium carbonate crystals in synovial fluid urate crystals in synovial fluid

General

synovial fluid analysis crystals in body fluid

References

  1. Laboratory Medicine: Test Selection & Interpretation. Howanitz & Howanitz (eds), Churchill Livingstone, NY, 1991, pg 119-121
  2. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 469-470
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998