Lab

Polarized Microscopy

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Polarized Microscopy, Synovial Fluid Crystals

  • Monosodium Urate (MSU) Crystals
  • Gout
  1. Needle-shaped
  2. Frequently intracellular
  3. Strongly negatively birefringent
  • Calcium Pyrophosphate Dihydrate (CPPD)
  • Pseudogout
  1. Rod or rhomboidal shaped
  2. Weakly positive birefringent
  • Basic Calcium Phosphate (BCP)
  • Calcific periarthritis
  1. Description
    1. Clumps and globules
    2. Non-birefringent
  2. Conditions
    1. Chronic BCP Arthritis
    2. Milwaukee Shoulder-knee syndrome
    3. Mixed BCP-CPPD disease (See above)
    4. Osteoarthritis
    5. Metastatic calcinosis
  • Calcium Oxalate
  1. Description
    1. Variable bipyramidal morphology
    2. Strongly positively birefringent
  2. Conditions
    1. Chronic dialysis Arthritis
    2. Arthritis of primary oxalosis
  • Cholesterol Crystals or Lipid Microspheres
  1. Description
    1. Flat, rectangular plates
    2. Notched corners, maltese crosses
    3. Strongly negative birefringent
  2. Conditions
    1. Chronic inflammatory Arthritis
    2. Acute Polyarthritis
  1. Polygonal Shaped
  2. Positively birefringent
  • Other Crystals
  1. Corticosteroid Crystals: Arthritis flare post injection
    1. Birefringent Crystals
  2. Cystine Crystals: Cystinosis
  3. Xanthine Crystals: Xanthinuria
  4. Charcot-Leyden Crystals: Hypereosinophilic syndromes
  5. Aluminum phosphate: Hemodialysis
  6. Talc from exam gloves (Artifact)
  7. Apatite (Stained by Alizarin red S)