calcium oxalate stones

Last reviewed 01/2018

Calcium oxalate stones are hard stones usually with a sharp, spiky surface which traumatize the urinary epithelium.

Causes include:

  • hypercalciuria without hypercalcaemia (50%)

  • hypercalciuria with hypercalcaemia (10%):
    • sarcoidosis
    • metastatic malignancy
    • multiple myeloma
    • vitamin D toxicity

  • hyperuricosuria +/- hypercalcaemia (20%):
    • associated with "nucleation" of calcium oxalate by uric acid crystals in the collecting ducts

  • hyperoxaluria (5%)

  • idiopathic (25%)