Tertiary hyperparathyroidism usually happens after long-term secondary hyperparathyroidism (see secondary hyperparathyroidism section) with the parathyroid glands reaching a stage where they lose any regulation and automatically secrete excess parathyroid hormone, whatever levels of calcium are circulating in the bloodstream. This causes high levels of calcium (hypercalcaemia) in the blood, the same as in primary hyperparathyroidism.
The most common cause of tertiary hyperparathyroidism is chronic kidney disease, which is often linked with secondary hyperparathyroidism. It can continue even after a kidney transplant. High phosphate levels, low levels of active vitamin d and hypocalcaemia, all typical symptoms of kidney disease, cause long-term parathyroid cell growth, which leads to nodular hyperplasia of the parathyroid gland. This, in turn, can cause growths known as nodular hyperplastic adenomas that usually occur in all four parathyroid glands, but sometimes in just one or two glands.
The signs and symptoms are usually similar to primary hyperparathyroidism with a risk of reduced bone density (osteoporosis), muscle weakness, bone and joint pain. This is because of the hypercalcaemia and raised parathyroid hormone caused by the condition.
It is very rare.
Tertiary hyperparathyroidism can occur in patients with hypophosphataemic rickets. Although it is very rare, the most common form of this condition is X-linked hypophosphataemic rickets, which is directly linked to an inherited abnormality on the X gene.
Blood tests will show raised calcium and parathyroid hormone levels. Phosphate levels can be variable, dependent on kidney function.
Tertiary hyperparathyroidism may be treated with a drug called Cinacalcet, however, it is usually treated through surgery, which involves partial or total removal of the parathyroid glands (parathyroidectomy). If there is total removal (all four glands are removed) a small piece of healthy parathyroid tissue can be implanted into the forearm to maintain some parathyroid hormone secretion or patients can take vitamin D and calcium supplements lifelong.
In the long-term treatment of patients with hypophosphataemic rickets, vitamin D stimulates the growth of parathyroid tissue, resulting in high levels of calcium and parathyroid hormone.
If all four parathyroid glands are removed, this will result in no production of parathyroid hormone, hypoparathyroidism may develop. This will need to be treated with activated forms of vitamin D. The risks of parathyroidectomy are the same as for primary hyperparathyroidism.
Tertiary hyperparathyroidism is associated with similar risks to those of primary hyperparathyroidism.
Last reviewed: Mar 2015