Dialysis Prescription
Lowering the dialysis calcium concentration may help correct the hypercalcemia quickly, particularly if the patient is symptomatic from the hypercalcemia. This will provide a stimulus to PTH formation and secretion. Dialysate Calcium of 1 mM is available and could be used instead of the usual 1.25 or 1.5 mM Ca.
Phosphate and Calcium Management
In the presence of a prior parathyroidecotmy, this constellation of biochemical findings suggests an imbalance between the vitamin D sterol replacement and the dose of calcium-based phosphate binders. A decrease in the dose of ingested calcium will allow the phosphate to rise and help correct the hypercalcemia.
A reduction in the calcium containing phosphate binder is required in this patient with hypercalcemia and low phosphate levels. This should allow the phosphate to rise and remove the inhibitory signal to PTH formation and release. If the phosphate rises too much, use of a non-calcium based binder may be helpful.
The aluminum binder should be discontinued in favor of a non-calcium, non-aluminum binder. A DFO challenge test to diagnose significant aluminum accumulation may be indicated here, but care must be taken to avoid precipitation of acute neurologic sequelae.
PTH Management
Excessive vitamin D sterol doses usually usually lead to hyperphosphatemia in addition to the hypercalcemia. However, if a vitamin D sterol is being used, the dose should be reduced.
Calcimimetic use should be reviewed and the dose be dropped or consideration be given to withdrawal of the agent. Sudden discontinuation of a calcimimetic has been associated with a rapid rise in PTH with loss of prior good control
Other Options of Controversies in Management
There have been very few studies examining the use impact of dialysate calcium level on calcium balance and serum levels. Most programs would consider 1.25 mM and 1.5 mM as standard dialysate calcium levels. Acid concentrates with 1 mM Ca are available and could be used to correct the high calcium and potentially stimulate an increase in PTH level.
Suggested References
1. Spasovski G et al. Improvement of Bone and Mineral Parameters Related to Adynamic Bone Disease by Diminishing Dialysate Calcium. Bone 2007; 41: 698–703.
2. Lezaic V, Pejanovic S, Kostic S et al. Effects of lowering dialysate calcium concentration on mineral metabolism and parathyroid hormone secretion: a multicentric study. Ther Apher Dial 2007
3. Molina Vila P, Sanchez Perez P, Garrigos Almerich E et al. Marked improvement in bone metabolism parameters after increasing the dialysate calcium concentration from 2.5 to 3 mEq/L in nonhypercalcemic hemodialysis patients. Hemodial Int 2008; 12: 73–79
4. Seyffart G, Schulz T, Stiller S. Use of two calcium concentrations in hemodialysis—report of a 20-year clinical experience. Clin Nephrol 2009; 71: 296–305
5. Toussaint N, Cooney P, Kerr PG. Review of dialysate calcium concentration in hemodialysis. Hemodial Int 2006; 10: 326–337
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