Calcium Stones

The majority of stones are predominantly composed of calcium, either in the form of calcium oxalate (70-75%) or calcium phosphate (5-10%). The risk factors for routine calcium oxalate stones are diverse, including hypercalciuria, hypocitraturia, hyperuricosuria, and low urine volumes. High urine pH is an important etiological risk for calcium phosphate stone formers, some of whom clearly have distal renal tubular acidosis, either genetic or acquired. Secondary causes for calcium stones include primary hyperparathyroidism, enteric hyperoxaluria, and primary hyperoxaluria. Treatment strategies are aimed at reducing urinary supersaturation, and include a combination of dietary modifications and drugs, each tailored toward a given patient's risk factors.