Phosphate homeostasis in Bartter syndrome: a case-control study.

BACKGROUND: Bartter patients may be hypercalciuric. Additional abnormalities in the metabolism of calcium, phosphate, and calciotropic hormones have occasionally been reported. METHODS: The metabolism of calcium, phosphate, and calciotropic hormones was investigated in 15 patients with Bartter syndrome and 15 healthy subjects. RESULTS: Compared to the controls, Bartter patients had significantly reduced plasma phosphate {mean [interquartile range]:1.29 [1.16-1.46] vs. 1.61 [1.54-1.67] mmol/L} and maximal tubular phosphate reabsorption (1.16 [1.00-1.35] vs. 1.41 [1.37-1.47] mmol/L) and significantly increased parathyroid hormone (PTH) level (6.1 [4.5-7.7] vs. 2.8 [2.2-4.4] pmol/L). However, patients and controls did not differ in blood calcium, 25-hydroxyvitamin D, alkaline phosphatase, and osteocalcin levels. In patients, an inverse correlation (P < 0.05) was noted between total plasma calcium or glomerular filtration rate and PTH concentration. A positive correlation was also noted between PTH and osteocalcin concentrations (P < 0.005), as well as between chloriduria or natriuria and phosphaturia (P < 0.001). No correlation was noted between calciuria and PTH concentration or between urinary or circulating phosphate and PTH. CONCLUSIONS: The results of this study demonstrate a tendency towards renal phosphate wasting and elevated circulating PTH levels in Bartter patients.

Preformed antibiotic-loaded cement spacers for two-stage revision of infected total hip arthroplasty. Long-term results.

Two-stage revision is the most widely accepted and performed intervention for chronically infected hip prosthesis and different interim spacers have been proposed. In recent years, antibiotic-loaded preformed spacers have become available on the market. The aim of this retrospective study was to assess the long-term results of two-stage revision with preformed spacers and uncemented hip prosthesis for the treatment of septic hip prosthesis. From 2000 to 2010, 183 consecutive patients underwent two-stage revision of septic hip prosthesis, with a same protocol, including preformed antibiotic-loaded cement spacer and a cementless modular hip revision prosthesis and four to six weeks antibiotic administration. Clinical and radiologic assessment at a minimum follow-up of two years was performed. At a minimum two years follow-up, 10 patients (5.4%) had had an infection recurrence, four (2.2%) an aseptic loosening and four more required partial revision of the modular components of the prosthesis, because of hip instability/dislocation; 21 patients died or were lost to follow-up. Considering all the reasons for revision, survivorship at eleven years was 93.9%. Harris Hip Score improved from 29.1 ± 14.6 pre-operatively to 41.1 ± 15.9 after spacer implant and 81.7 ± 17.6 after hip revision. The main complications after spacer implant included: spacer dislocation (16.4%), intra-operative femoral fractures (2.7%), and thromboembolism (2.1%). Complications after hip revision were: instability/dislocation (4,3%), intra-operative femoral fractures (1.6%), and thromboembolism (3.3%). Two-stage revision of septic hip prosthesis with preformed antibiotic-loaded spacers and cementless hip prosthesis provides satisfactory long-term results, with reduced complications.