This is a disorder with abnormal parathyroid hormone (PTH) secretion which controls:Hyperparathyoidism causes an excess PTH level which is the most common cause of hypercalcemia
serum Calcium and Phosphorus levels
reabsorption of calcium from bones and kidneys
activation of Vitamin D from inactive to active for
There are 3 types:
Primary - oversecretion of PTH
Onset is between 30 - 70 years old with a peak incidence in the 4th and 5th decade of life
People at risk are those who have had radiation to their head and neck
retrospective studies show that patients treated for tuberculosis adenitis showed no risk with radiation doses below 50rad, but increased 50% risk if doses were above 1200rad (Pyram, 2011).
Acne irradication accounts for 2-3 times increase in this disease (Pyram, 2011)
80-85% and most common cause is parathyroid adenoma
cyclin D1 (protooncogene) and MEN-1 (tumor supressor gene) abnormalities are responsible for the sporatic adenoma development
Familial hypocalciuric hypercalcemia is an autosomal dominant condition which mimics hyperparathyroidism (Pallan, 2009)
Secondary - compensatory response to conditions that originally caused hypocalcemia
ie. Vitamin D deficiency, malabsorption, chronic renal failure, hyperphosphatemia
Tertiary - hyperplasia of parathyroid glands and lost of negative feedback from circulating calcium levels causing random PTH secretion even in normocalcemia
Will see in kidney transplant patients after long term dialysis for chronic kidney disease
Hyperparathyroidism
Pathophysiology