The disease of hyperparathyroidism is diverse.  The causes of it are very different.  As a simplification there’s primary, secondary and tertiary hyperparathyroidism:

All three of these involves increased PTH (parathyroid hormone)

Primary: elevated calcium, low phosphorus in blood stream.  Usually caused by a parathyroid adenoma.

Secondary: normal or low calcium, usually caused by renal failure.

Tertiary: failure of treatment of secondary hyperparathyroidism to correct increased PTH.

More details on hyperparathyroidism

Primary hyperparathyroidism is most commonly caused by adenomas, greater than 85%.  Next most common cause would be hyperplasia which is 10% of the causes, and there is a 1% possibility that primary hyperparathyroidism is caused by a carcinoma.

Risk factor for primary hyperparathyroidism includes family history, MEN I and MEN IIa, and also radiation.  Major difference between MEN IIA and IIB:  MEN IIA has Hyperparathyroidism – hyperplasia, MEN IIB does not.  More on MEN syndromes.

Sestamibi scan is a method of detecting hyperparathyroidism.

Carcinomas which are commonly associated with hypercalcemia:

• Breast Cancer Metastasis
• Postate Cancer
• Kidney Cancer
• Lung Cancer

Another cause of hypercalcemia:  FHH – Familial hypocalciuric hypercalcemia

• autosomal dominant
• asymptomatic hypercalcemia and low urine calcium
• with or without elevated PTH
• No treatment is generally required for FHH