Primary hyperparathyroidism 

Secondary hyperparathyroidism

Findings -

This is treated by correcting the vitamin D deficiency or performing a renal transplant to treat renal failure.

Tertiary hyperparathyroidism

Secondary hyperparathyroidism causing hyperplasia of the glands = An increase in the baseline levels of PTH

Then when the cause of the secondary hyperparathyroidism is treated the parathyroid hormone level remains inappropriately high. This high level of parathyroid hormone in the absence of the previous pathology leads to high absorption of calcium in the intestines, kidneys and bones and causes hypercalcaemia. This is treated by surgically removing part of the parathyroid tissue to return the parathyroid hormone to an appropriate level.

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