How is hyperparathyroidism diagnosed?
There are two basic blood tests that tell the story for hyperparathyroidism. Calcium and PTH (parathyroid hormone).
High Calcium + High PTH
If your blood tests show high values on both of these - you have a parathyroid tumor. This is called primary hyperparathyroidism. This is caused by one or more tumors of the parathyroid glands - there are no other causes. This scenario is found in 75% of patients with primary hyperparathyroidism. There are no medicines to treat this condition; none that avoid complications and none that reverse the abnormality. The only treatment is surgical and it is completely curative.
High Calcium + Normal PTH
This is also likely to be primary hyperparathyroidism! In fact, about 20% of primary hyperparathyroid conditions present this way. When calcium is high, the normal response from normal functioning parathyroid glands would produce a low PTH value. Because PTH is produced on a feedback system, increasing levels of calcium should result in decreasing levels of PTH.
Normal Calcium + High PTH
This is the most difficult group to sort out. About 5% of patients with primary hyperparathyroidism present with this scenario. Other signs of problems with calcium are usually present (think kidney stones) and often ionized calcium will be elevated. If hypocalcemia (low blood calcium) is present, then it would be normal for the body to produce high levels of PTH to correct this abnormality. But, PTH levels should fall the moment calcium enters the low-normal range. We call this situation secondary hyperparathyroidism and it is seen rarely. Patients with end stage renal disease (about to go on dialysis) may fall in to the secondary hyperparathyroidism category. Patients with poor gastrointestinal absorption may also be in this category; these patients may have a history of stomach banding, stapling or stomach bypass. Severe Celiac disease, Crohn's disease, or severe vitamin D deficiency can be underlying factors - but nearly always the calcium levels are low.