Bone disease in idiopathic hypercalciuria.
OBJECTIVE
Decreased bone mineral density and increased prevalence of bone fractures have been found in patients with idiopathic hypercalciuria. The purpose of this review is to summarize the recent published evidence that supports a potential role of the bone, and its link to the kidney and intestine, in the pathogenesis of idiopathic hypercalciuria. The effects of hypercalciuria on bone and the implications for treatment are also reviewed.


RESULTS
Evidence suggests that the incidence of a first fracture in kidney stone patients is fourfold higher than the control population. Support for the role of bone in the pathophysiology of hypercalciuria has been corroborated. New studies have detailed the effects of several cytokines - increased number and sensitivity of vitamin D receptors, and increased acid production - upon the bone acting cells. Similarly, recent clinical and experimental studies have suggested that genetic factors confer a predisposition to the formation of renal calcium stones and bone demineralization.


CONCLUSIONS
Whether hypercalciuria is the result of a primary bone disorder, a consequence of a persisting negative calcium balance or a combination of both still remains to be determined. Nevertheless, bone status must be evaluated and followed up in patients with idiopathic hypercalciuria.
Heilberg
Ita P
IP
Division of Nephrology, Universidade Federal de São Paulo, São Paulo, Brazil.
Weisinger
José R
JR
D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D002118:Calcium / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D050723:Fractures, Bone / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D006801:Humans; D007669:Kidney Calculi / Q000150:complications / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D008297:Male; D018167:Receptors, Calcitriol / Q000378:metabolism
D016207:Cytokines; D018167:Receptors, Calcitriol; D002118:Calcium