A Parathyroid scan or Sestamibi scan may be needed if the typical weight loss surgical reasons for elevated PTH levels have been addressed. Sestamibi is a small protein which is labeled with the radio-pharmaceutical technetium-99. This very mild and safe radioactive agent is injected into the veins of a patient with overactive parathyroid and is absorbed by the overactive parathyroid gland. If the parathyroid is normal it will not absorb the agent. The scan below shows the uptake of the agent.
Calcium, Vitamin D and Parathyroid hormone are routinely measured on yearly follow up for most post weight loss surgical (WLS) patients. Elevated parathyroid hormone (PTH) may be caused by Vitamin D deficiency or calcium deficiency (most common in post WLS) or by over active parathyroid gland(s). In the latter case, if one of the four glands is overactive then this is knows as a parathyroid Adenoma. If all 4 are over active and are secreting too much PTH, this is known as hyperplasia. Ultrasound of the neck, may identify an enraged parathyroid gland (adenoma) which is located behind the thyroid gland. Given the large area where the parathyroid gland may be located, additional tests are needed to not only identify the location of the gland(s) but also to distinguish between single gland (adenoma) or multiple glands (hyperplasia) cause for the elevated PTH. It is important to investigate all avenues and testing in parathyroid hormone elevation and in some cases, not to rely on one test for your diagnosis. It is also imperative that weight loss surgical patients take their supplements routinely and consistently and have their laboratory studies followed at least yearly.