Hypercalcemia

A disorder of the parathyroid gland which causes an abnormally high level of calcium in the blood resulting from the overproduction of parathyroid hormone.  Symptoms are fatigue, nausea, abdominal pain, mental confusion, heart arrhythmias, or seizures.  It may also cause osteoporosis.  The calcium removed from the bones is excreted in large amounts from the urine, often causing kidney stones.