Should patients with single renal stone occurrence undergo diagnostic evaluation?

Diagnostic evaluation was conducted on 34 patients with a single episode of renal stone formation. Absorptive hypercalciuria was disclosed in 55.9 per cent (23.5 per cent type I and 32.4 per cent type II), renal hypercalicuria in 11.8 per cent, primary hyperparathyroidism in 2.9 per cent, hyperuricosuric calcium oxalate nephrolithiasis in 8.8 per cent and no metabolic abnormality in 20.6 per cent. Compared to the group with recurrent stone formation the group with a single stone episode had just as severe biochemical abnormalities or laboratory results, such as hypercalciuria and exaggerated calciuric response to oral calcium load in absorptive hypercalciuria, high fasting urinary calcium and cyclic adenosine monophosphate in renal hypercalciuria, hyperuricosuria in hyperuricosuric calcium oxalate nephrolithiasis and low urine volume in no metabolic abnormality. The results suggest that the same physiological and environmental disturbances characterize stone formation in patients with a single stone episode as in those with recurrent stone formation and indicate the need for diagnostic evaluation.