When blood calcium levels drop below a certain level, PTH is released, which stimulates bone destruction cells to release calcium from bone into the blood. Although the skeleton is the major target of PTH, this hormone also stimulates the kidneys and intestine to absorb more calcium. PTH operates in balance with calcitonin, a thyroid hormone. PTH acts to increase calcium levels in blood, and decrease bone levels of calcium, whereas calcitonin increases calcium levels in bone and decreases calcium levels in the blood. It is important that PTH and calcitonin act in equilibrium.
Severe hyperparathyroidism can cause bone destruction, resulting in bone fragility.
131 I in the thyroid gland may cause tumors in the adjacent parathyroid glands. Tumors in the parathyroid glands often cause hyperparathyroidism and hypercalcemia. Symptoms are typically vague, and the disorder is usually diagnosed when blood tests indicate too much calcium in the blood. Because these symptoms are also common to other diseases, a person displaying these symptoms may not necessarily have hyperparathyroidism. If you have any symptoms, please see your medical provider.