Uroliths composed predominantly of calcium phosphates have been infrequentl
y identified in dogs. Factors incriminated in the etiopathogenesis of calci
um phosphate urolithiasis include an alkaline urine pH, hypercalciuria, dec
reased urine concentrations of crystallization inhibitors, and increased ur
ine concentrations of crystallization promoters. Disorders associated with
calcium phosphate urolith formation in dogs include primary hyperyarathyroi
dism, hyperadrenocorticism, and idiopathic hypercalciuria. Medical therapy
of patients with recurring calcium phosphate uroliths should be directed at
removing or minimizing factors contributing to urine supersaturation with
calcium phosphate.