The impact of renal transplantation on trabecular and cortical bone mineral density (BMD) and cortical structure is unknown. We obtained quantitative computed tomography scans of the tibia in pediatric renal transplant recipients at transplantation and 3, 6, and 12 months; 58 recipients completed at least two visits. We used more than 700 reference participants to generate Z-scores for trabecular BMD, cortical BMD, section modulus (a summary measure of cortical dimensions and strength), and muscle and fat area. At baseline, compared with reference participants, renal transplant recipients had significantly lower mean section modulus and muscle area; trabecular BMD was significantly greater than reference participants only in transplant recipients younger than 13 years. After transplantation, trabecular BMD decreased significantly in association with greater glucocorticoid exposure. Cortical BMD increased significantly in association with greater glucocorticoid exposure and greater decreases in parathyroid hormone levels. Muscle and fat area both increased significantly, but section modulus did not improve. At 12 months, transplantation associated with significantly lower section modulus and greater fat area compared with reference participants. Muscle area and cortical BMD did not differ significantly between transplant recipients and reference participants. Trabecular BMD was no longer significantly elevated in younger recipients and was low in older recipients. Pediatric renal transplant associated with persistent deficits in section modulus, despite recovery of muscle, and low trabecular BMD in older recipients. Future studies should determine the implications of these data on fracture risk and identify strategies to improve bone density and structure. During childhood and adolescence, skeletal development is characterized by increases in trabecular and cortical bone mineral density (BMD) and cortical dimensions. 1 Children with CKD have numerous risk factors for impaired bone acquisition, including growth failure, delayed puberty, malnutrition, acidosis, vitamin D deficiency, muscle deficits, and secondary hyperparathyroidism. Successful renal transplantation corrects many of the underlying abnormalities contributing to bone deficits in childhood CKD. However, immunosuppressive therapies and persistent hyperparathyroidism may impair recovery of bone structure and strength. The risk of fracture among adult renal transplant recipients increases in the months after transplantation and then gradually declines. 2 The

Amino acids, uric acid, and organic acids together accounted for only 7.9% of the SIG in intensive care unit patients with metabolic acidosis.

In critically ill patients with metabolic acidosis, impaired renal function was associated with greater urinary SIDs. Subsequently, the higher urinary SIDs values were related to lower pH levels, illustrating the importance of renal chloride excretion to correct for acidosis.

This prospective study evaluated changes in DXA whole body bone mineral content (WB-BMC) and spine areal bone mineral density (spine-BMD), and tibia quantitative CT (QCT) trabecular and cortical volumetric BMD and cortical area in 56 children over 12 months following renal transplantation. At transplant, spine-BMD Z-scores were greater in younger recipients (<13 years), vs. 898 reference participants (p<0.001). In multivariate models, greater decreases in spine-BMD Z-scores were associated with greater glucocorticoid dose (p<0.001) and declines in parathyroid hormone levels (p=0.008). Changes in DXA spine-BMD and QCT trabecular BMD were correlated (R=0.47, p<0.01). At 12 months, spine-BMD Z-scores remained elevated in younger recipients, but did not differ in older recipients (≥13) and reference participants. Baseline WB-BMC Z-scores were significantly lower than reference participants (p=0.02). Greater glucocorticoid doses were associated with declines in WB-BMC Z-scores (p<0.001) while greater linear growth was associated with gains in WB-BMC Z-scores (p=0.01). Changes in WB-BMC Z-scores were associated with changes in tibia cortical area Z-scores (R=0.52, p<0.001), but not changes in cortical BMD Z-scores. Despite resolution of muscle deficits, WBBMC Z-scores at 12 months remained significantly reduced. These data suggest spine and whole body DXA provide insight into trabecular and cortical outcomes following pediatric renal transplantation.