What are the main complications happen in parathyroid glands?

Hormone changes: The parathyroid glands produce a hormone called pth. The production of this hormone is controlled by the serum levels of calcium. If the production become independent of the calcium level due to a benign tumor of the gland, overproduction occurs. If the glands are injured through radiation or surgery of other means, low production may result.

Enlarged or absent.: Parathyroid glands (one or more) may enlarge and cause a high blood calcium and lead to kidney stones and bone loss. If high enough symptoms may occur such as mental changes, constipation, frequent urination and weakness. In kidney failure parathyroid glands enlarge but often the blood calcium is low. Absence of parathyroid glands most often is due to thyroid surgery. The blood calcium is low.