Role of stone analysis in metabolic evaluation and medical treatment of nephrolithiasis.
OBJECTIVE
Comprehensive metabolic evaluation has become an important aspect of the management of recurrent nephrolithiasis, yet the role of stone analysis is often neglected or perhaps underestimated. The purpose of this study was to determine the role of stone analysis in medical decision making in patients with recurrent nephrolithiasis.


METHODS
We evaluated 100 consecutive stone-forming patients who had undergone compositional stone analysis as well as comprehensive metabolic evaluation at our institution. An analysis of stone composition in relation to metabolic disturbances was performed. Patients were stratified into two groups: calcium and non-calcium stone formers.


RESULTS
Patients having non-calcium stones were found to have a metabolic analysis reflecting specific metabolic disorders. Alternatively, patients with calcium stones were heterogeneous with regard to metabolic disorders, but there was a significant likelihood of renal tubular acidosis in those patients with calcium phosphate calculi. On the basis of these results, a simplified metabolic evaluation and nonselective medical therapy based on stone composition was formulated to facilitate assessment, management, and monitoring of stone disease.


CONCLUSIONS
Compositional stone analysis should be an integral part of the metabolic evaluation of patients with nephrolithiasis. Moreover, stone analysis alone may provide guidance for therapeutic treatment and obviate a formal metabolic evaluation.
Kourambas
J
J
Duke Comprehensive Kidney Stone Center, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
Aslan
P
P
Teh
C L
CL
Mathias
B J
BJ
Preminger
G M
GM
D000141:Acidosis, Renal Tubular / Q000150:complications; D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D003553:Cystine / Q000032:analysis; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry* / Q000188:drug therapy* / Q000209:etiology; D017616:Magnesium Compounds / Q000032:analysis; D008297:Male; D008659:Metabolic Diseases / Q000175:diagnosis / Q000188:drug therapy; D010710:Phosphates / Q000032:analysis; D000069877:Struvite; D014527:Uric Acid / Q000032:analysis
D002130:Calcium Phosphates; D017616:Magnesium Compounds; D010710:Phosphates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D014527:Uric Acid; D003553:Cystine; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D000069877:Struvite; C485829:calcium phosphate, dibasic, anhydrous; D002118:Calcium