Category Archives: Hyperparathyroidism

Hyperparathyroidism – primary, secondary, tertiary – simplified

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


Sestamibi scan

Sestamibi Parathyroid Scan

  • It’s a nuclear scan to localize parathyroid adenomas.
  • Tc99m-sestamibi is absorbed faster by a hyperfunctioning parathyroid gland
  • Allows the surgeon to remove the one gland of the 4 parathyroids which is hyperfunctioning – minimally invasive parathyroidectomy.
  • Sestamibi scan only detects only about 70% of HPT lesions.  So don’t discard the diagnosis of HPT when the sestamibi scan is negative.
  • Hyperparathyroidism is the excess of parathyroid hormone (PTH) in the blood stream.  Primary hyperparathyroidism (Primary HPT) has lab values of high calcium and high PTH.  Secondary hyperparathyroidism has lab values of low calcium and high PTH.  Most common cause of secondary HPT is chronic renal failure.  (treatment is possibly renal transplantation).
  • Sestamibi scan is to detect parathyroid hyperfunctioning which then is a cause of primary HPT.