Transplant recipients on the edge of the hypocalcemia abyss.

Hypovitaminosis D is a risk factor for transplant-related osteoporosis. Its contribution to severe hypocalcemia in transplant recipients is less well recognized. We present 2 cases to illustrate how risk factors specific to transplant recipients significantly increase the risk of development of severe hypocalcemia, on a background of unrecognized vitamin D deficiency. Regular surveillance of calcium homeostasis should be incorporated into routine clinical care of transplant recipients.