尿路結石再発に関する臨床的検討 (5)結石組成と尿pH日内変動および結石構成物質の尿中排泄の関係について

Abstract

58例を対象に結石組成と尿pHの日内変動および結石構成物質の尿中排泄量の関係を検討した.尿酸結合症例では尿pHは常に低く, リン酸Caやリン酸Mgアンモニウム結石症例では尿pHは常に高くともに日内変動はなかった.これに反して蓚酸Ca結石症例では早朝の尿pHは低く, 日中の尿pHは上昇し, 夜間再び低下するという典型的な日内変動がみられた.蓚酸Ca・リン酸Ca混合結石症例では早朝の尿pHは蓚酸Ca結石症例より高く, 日中は同様に尿pHが上昇するが, 夜間尿pHは低下しなかった.一方, 蓚酸Ca・リン酸Ca混合結石症例では蓚酸Ca結石症例より有意に尿中Ca排泄が高かったが, それ以外には結石組成の差により尿中結石構成物質排泄量に違いがなかった.以上より, 尿pHの日内変動と尿中Caは結石組成の決定に際し重要な役割を果す可能性が示唆された

Correlation of the composition of the urinary calculi with urine pH, especially of diurnal variation, and composition of urinary excretion was studied. Urine pH in the patients with uric acid stones was constantly low and urinary pH in the patients with apatite and struvite stones was always high. Diurnal variation was not observed. In patients with pure calcium oxalate stones, however, urinary pH was low in the early morning, increased during the daytime, and was lowered at night. In the patients with mixed calcium oxalate-phosphate stones, a similar diurnal variation in urinary pH was found, but the urinary pH in the early morning was significantly higher in the patients with mixed calcium oxalate-phosphate stones than in those with pure calcium oxalate stones. Urinary tract infection did not influence these differences in urinary pH. Urinary excretion of calcium in the patients with mixed calcium oxalate-phosphate stones was significantly higher than that in those with pure calcium oxalate stones. No other correlations were observed between composition of the urinary calculi and urinary excretion of calcium, oxalate, uric acid, phosphate or magnesium. From these findings we conclude that urinary pH and urinary calcium are the most important factors determining the composition of the urinary calculi.