Unusual cause of hypercalcaemia in end stage renal failure patients

Immobility-induced hypercalcaemia is rarely considered in patients on dialysis and is a challenging diagnosis to make. This is especially so due to the lack of biomarkers as well as the notion that calcium metabolism is mostly related to chronic kidney disease-metabolic bone disorder due to the role of iPTH. We present two cases of our dialysis patients, who were clinically unwell from hypercalcemia. We were initially uncertain of the cause of hypercalcemia as despite our attempts to adjust treatment based on their biochemical findings, we were unable to correct the hypercalcemia. We did not have appropriate bone turnover markers to guide us and out of desperation, anti-resorptives-calcitonin and bisphosphonate were given with good clinical response. We concluded that the hypercalcemia was related to immobility-induced hypercalcemia and the inappropriately low iPTH was a red herring. Immobility-induced hypercalcaemia should be considered in patients with end stage renal failure on renal replacement therapy, especially in those with recent and significant immobility. In these patients, pamidronate can be considered should the hypercalcaemia persist.