Causes and Risks:

Parathyroid hyperplasia may occur sporadically (without a family history) or as part of three familial (inherited) syndromes: MEN (multiple endocrine neoplasia) 1; MEN2A; and isolated familial hyperparathyroidism.

In MEN1, the cause is an absent gene, with resulting problems in the parathyroids. In MEN2A, mutations of a gene are activated and cause the condition. The genetic basis of isolated familial parathyroidism is not yet clear.

Prevention: Patients with a family history of the MEN syndromes may be gentically screened and screened with standard diagnostic methods for endocrine problems.

Symptoms:

Symptoms of hyperparathyroidism may include:

• lethargy
• renal stones
• nausea
• constipation
• myalgia (muscle pain)
• bone fractures

Signs and Tests:

Signs of hyperparathyroidism may include:

• bone fractures
• renal colic

Tests may show:

• elevated serum calcium
• low serum phosphorus
• elevated intact PTH
• elevated serum chloride
• low serum bicarbonate
• elevated 24 hour urine calcium
• low bone mineral density

Treatment: Surgery is the preferred treatment. Usually 3 1/2 glands are removed. The remaining tissue may be implanted in the forearm to regulate calcium levels but allow easy surgical access if hypercalcemia recurs.

Prognosis: The success rate for surgery for parathyroid hyperplasia is lower than that for parathyroid adenoma. Persistent or recurrent hypercalcemia occurs about 20% of the time.

Complications:

Advanced complications of hyperparathyroidism include nephrocalcinosis and osteitis fibrosa cystica.

Patients may also have complications from the other endocrine tumors which are part of the multiple endocrine neoplasia syndromes:

MEN1 -- includes pancreatic and pituitary tumors, adrenal adenomas, and lipomas.

MEN2A -- includes medullary carcinoma of the thyroid and pheochromocytoma.

Call your health care provider if you have any symptoms of hypercalcemia, or there is a family history of any of the MEN syndromes