Hypercalcemia is an abnormally high level of calcium in the blood. It can be caused by high levels of parathyroid hormone (PTH) and may occur in hyperparathyroidism, chronic kidney disease, or following kidney dialysis or kidney transplant.

Hypercalcemia can also develop without high levels of PTH. This occurs in vitamin D overdose, prolonged periods of bed rest or immobilization, hyperthyroidism, multiple myeloma, and involvement of the bones by other cancers.

Symptoms of hypercalcemia include dehydration, confusion, and extreme tiredness. Loss of appetite, nausea, vomiting, weight loss, and constipation occur when symptoms of hypercalcemia involve the gastrointestinal tract.