- Email: [email protected]
Re: Urine Risk Factors in Children with Calcium Kidney Stones and Their Siblings
UROLITHIASIS/ENDOUROLOGY
1339
with minimal peripheral blood flow. Scrotal exploration was performed, confirming extravaginal torsion; both testes underwent orchiopexy. Subsequent imaging demonstrated normal bilateral testes with good vascular flow. Although intervention of prenatal torsion has been debated, the present case represents prenatal torsion saved by intervention. We propose the presence of any blood flow suggests incomplete torsion and the potential for salvage. Editorial Comment: The authors report the first successful salvage of a twisted spermatic cord in a newborn. Although followup was short (1 month) and only incomplete torsion was noted during exploration, this episode provides additional support for the practice of immediate exploration of the newborn with spermatic cord torsion with the intent of detorsing the affected side and, more importantly, fixing the contralateral side. Douglas A. Canning, M.D.
Urolithiasis/Endourology Re: Urine Risk Factors in Children with Calcium Kidney Stones and Their Siblings K. J. Bergsland, F. L. Coe, M. D. White, M. J. Erhard, W. R. Defoor, J. D. Mahan, A. L. Schwaderer and J. R. Asplin Nephrology Section, Department of Medicine, University of Chicago, Chicago, Illinois Kidney Int 2012; 81: 1140 –1148.
Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. Editorial Comment: There is a paucity of good studies profiling the metabolic risk factors for stone formation in children. The authors demonstrated that higher calcium excretion is a risk factor for kidney stones. They also found a positive correlation between calcium excretion and stone recurrence. Risk factors identified in adults, such as increased oxalate and reduced citrate excretions, did not influence stone risk in children. The higher calcium excretion in a sibling is most likely consistent with the genetic influence on calcium as the investigators indirectly controlled for dietary effects. They also showed that the smaller gap between the supersaturation of calcium phosphate and its upper limit of metastability is a risk factor for stone formation and recurrence. These results suggest that efforts should be made to reduce calcium excretion in this patient cohort. However, this approach must be subjected to the scientific scrutiny of properly designed and performed clinical trials. Dean Assimos, M.D.
1339
with minimal peripheral blood flow. Scrotal exploration was performed, confirming extravaginal torsion; both testes underwent orchiopexy. Subsequent imaging demonstrated normal bilateral testes with good vascular flow. Although intervention of prenatal torsion has been debated, the present case represents prenatal torsion saved by intervention. We propose the presence of any blood flow suggests incomplete torsion and the potential for salvage. Editorial Comment: The authors report the first successful salvage of a twisted spermatic cord in a newborn. Although followup was short (1 month) and only incomplete torsion was noted during exploration, this episode provides additional support for the practice of immediate exploration of the newborn with spermatic cord torsion with the intent of detorsing the affected side and, more importantly, fixing the contralateral side. Douglas A. Canning, M.D.
Urolithiasis/Endourology Re: Urine Risk Factors in Children with Calcium Kidney Stones and Their Siblings K. J. Bergsland, F. L. Coe, M. D. White, M. J. Erhard, W. R. Defoor, J. D. Mahan, A. L. Schwaderer and J. R. Asplin Nephrology Section, Department of Medicine, University of Chicago, Chicago, Illinois Kidney Int 2012; 81: 1140 –1148.
Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. Editorial Comment: There is a paucity of good studies profiling the metabolic risk factors for stone formation in children. The authors demonstrated that higher calcium excretion is a risk factor for kidney stones. They also found a positive correlation between calcium excretion and stone recurrence. Risk factors identified in adults, such as increased oxalate and reduced citrate excretions, did not influence stone risk in children. The higher calcium excretion in a sibling is most likely consistent with the genetic influence on calcium as the investigators indirectly controlled for dietary effects. They also showed that the smaller gap between the supersaturation of calcium phosphate and its upper limit of metastability is a risk factor for stone formation and recurrence. These results suggest that efforts should be made to reduce calcium excretion in this patient cohort. However, this approach must be subjected to the scientific scrutiny of properly designed and performed clinical trials. Dean Assimos, M.D.