Bone Disease in Medullary Sponge Kidney and Effect of Potassium Citrate Treatment

Abstract

Design, setting, participants, & measurements: These issues were retrospectively analyzed in 75 patients with MSK and primary stone risk factor (PSRF; hypercalciuria, hypocitraturia, hyperuricosuria, and/or hyperoxaluria) on an outpatient basis; 65 received CA (2.9 ؎ 0.8 g/d), whereas 10 received only general "stone clinic" suggestions. The 24-h urinary excretion of calcium, phosphate, oxalate, uric acid, and citrate; morning urine pH; serum biochemistry; and bone mineral density were investigated at baseline and at the end of follow-up (78 ؎ 13 and 72 ؎ 15 mo in groups A and B, respectively).Results: CA led to a significant rise in urinary pH and citrate and decreased urinary calcium and phosphate (all P < 0.001). Patients with MSK and PSRF had reduced bone density. Bone density improved significantly in the group that was treated with oral CA.Conclusions: Bone disease is very frequent in patients with MSK and concomitant PSRF. Long-term CA improves bone density. The concurrent effects of treatment on PSRF suggest that the subtle acidosis plays a pivotal role in bone disease and hypercalciuria in patients with MSK.

Long-Term Treatment with Potassium Citrate and Renal Stones in Medullary Sponge Kidney

“…As in other clinical conditions characterized by hypercalciuria and/or renal tubular acidosis, patients with MSK also have reduced bone density, as we have recently shown (7).…”

“…Furthermore, we studied other clinical features of the disease (family history, clinical presentation, etc.). Results of the analysis are reported here, which goes hand in hand with the previously cited paper (7).…”

Correction of Metabolic Acidosis with Potassium Citrate in Renal Transplant Patients and its Effect on Bone Quality

“…Similarly, vitamin D metabolites and iPTH also remained unaffected. This is in accordance with other human clinical trials, although some studies report alterations in these parameters from potassium citrate treatment (24,27,28).…”

“…Several studies have documented clinically relevant bone disturbances in renal transplant patients such as osteopenia (6), osteomalacia (3), and bone turnover disorders (2). Similarly, alkali therapy has been shown to be beneficial for bone structure and bone metabolism in nontransplant populations (24,27,29). To our knowledge, ours is the first study to investigate the effect of alkali therapy on bone quality in renal transplant patients.…”

“…However, their clinical trial was conducted in postmenopausal women devoid of any acid/base disorders and steroid treatment. In patients with medullary sponge kidney, T and Z scores of lumbar spine improved significantly after potassium citrate treatment, but duration of alkali therapy was of at least 12 months and up to 8 years, raising the question regarding the influence of treatment duration on alterations in BMD (27). A significant enhancement of areal BMD at both the total hip and the trochanter was observed in 10 patients with distal renal tubular acidosis after 12 months of potassium citrate treatment.…”