Intraoperative monitoring of parathyroid hormone during adenoma removal: a post-excision value that does not decrease relative to the second baseline most likely indicates?

• A. Multigland disease
• B. Successful single-gland removal
• C. No change in PTH
• D. Measurement error

Answer: (A)

The key idea is what intraoperative PTH monitoring tells us about completeness of removal. PTH has a very short half-life, so if you remove the true single source of excess hormone, PTH should fall rapidly. A second baseline is used to compare the post-excision level and confirm that the drop is real. If the post-excision PTH value does not fall relative to that second baseline, it means another source of PTH remains active. That situation most commonly points to multigland disease or parathyroid hyperplasia, where more than one gland is overproducing PTH. So the persistent PTH signal after removing one gland strongly suggests additional hyperfunctioning tissue is present.