Effects of parathyroidectomy on tumoral calcinosis in uremic patients with secondary hyperparathyroidism.

BACKGROUND: Tumoral calcinosis (TC) is a rare disease derived from uremic secondary hyperparathyroidism (SHPT). However, parathyroidectomy (PTX) seems to be ineffective at relieving TC in some patients. In this study, we investigated the relationship between PTX and TC shrinkage. METHODS: We retrospectively followed up nine TC patients who underwent PTX, dividing them into two groups: those with TC size reduced by > 80% were in the "effective group" (group A), and the rest in the "ineffective group" (group B). RESULTS: We enrolled nine patients (7 men; mean age 38.6 ± 10.9 years) with SHPT-related TC. One patient with calciphylaxis was excluded due to sudden death. The efficiency of PTX in causing TC regression was 62.5% (5 patients in group A). Group A had a shorter overall duration of TC (6 [5.5, 6.0] vs. 9 [8.0, 10.0] months; P = 0.02) and higher serum levels of alkaline phosphatase (ALP; 408.0 [217.9, 1101.7] vs. 90.8 [71.0, 102.1] pg/ml; P = 0.03) and high-sensitivity C-reactive protein (hs-CRP; 82.7 [55.0, 112.4] vs. 3.1 [3.1, 4.5] mg/l; P = 0.02). Average calcium supplementation within 1 week of surgery was significantly greater in group A than in group B (96.8 [64.1, 105.3] vs. 20.1 [13.1, 32.7] g; P = 0.04). Patients in both the groups demonstrated similar serum phosphate levels before PTX, but these levels were higher in group B than in group A at follow-up times (3 months, P = 0.03; 6 months, P = 0.03). CONCLUSIONS: The shorter duration of pre-existing TC and higher ALP levels before PTX, as well as lower serum phosphate levels after PTX, were correlated with effective SHPT-TC shrinkage.

New modes of continuous renal replacement therapy using a refiltering technique to reduce micronutrient loss.

INTRODUCTION: Micronutrient depletion is a major drawback of high-dose continuous renal replacement therapy (CRRT). We tested two novel CRRT modes, double-filtration hemofiltration (DHF) and dialysate-recycling hemodiafiltration (DHDF), aimed at reducing micronutrient loss while maintaining a high clearance rate of midsized solutes comparable to that of high-volume hemofiltration (HVHF). METHODS: Forty patients with renal failure requiring CRRT were randomly assigned to receive predilutional standard-volume hemofiltration (SVHF, effluent rate 35 mL/kg/h), predilutional HVHF (100 mL/kg/h), DHF (35 mL/kg/h), and DHDF (30 mL/kg/h). In the two novel modes of CRRT, part of the high-volume primary effluent fluid produced by a high-flux filter (AV600S) was refiltered by two low-flux filters (15 L) for recycling as replacement fluid in DHF and dialysate in DHDF, while the remainder was discarded as final effluent fluid. Specimens were collected for measurement of trace elements, folic acid, amino acids (AAs), ß2-microglobulin, cystatin C, and creatinine and for calculation of solute clearance. FINDINGS: The clearance of 17 AAs, phosphorus, folic acid, copper, and zinc by DHF and DHDF was much lower than that by HVHF and comparable to that by SVHF. The estimated amount of AA loss by SVHF, HVHF, DHF, and DHDF was 10.3 (7.2-13.4) g/d, 22.1 (17.8-24.0) g/d, 10.6 (8.6-14.0) g/d, and 10.0 (8.6-11.4) g/d, respectively. Clearance of cystatin C and ß2-microglobulin by DHF and DHDF was much greater than that by SVHF and equal to that by HVHF. DISCUSSION: Compared to HVHF, DHF, and DHDF have an equal capacity for removal of large solutes but show substantially reduced micronutrient loss.