Teaching Points:

• Calcium oxalate crystals
  • Seen in patients with ethylene glycol toxicity, leading to renal failure
  • Urine microscopy notable for envelope-shaped or dumb bell shaped crystals
• Uric Acid crystals
  • Seen in high uric acid excretion states (tumor lysis syndrome)
  • Urine microscopy notable for rhomboid shaped crystals
• Struvite crystals
  • Seen in urine infections with bacteria that produce basic pH
  • Examples include ureaplasma urealyticum infections
  • Formation of magnesium ammonium phosphate crystals
  • Urine microscopy notable for coffin-shaped crystals
• Cystine crystals
  • Seen in patients with cysteinuria
  • Urine microscopy notable for hexagon-shaped crystals