Linkages between the Ultradian Patterns of Growth Hormone and Ghrelin: External versus Internal Cueing

Abstract

Primary hyperparathyroidism is the commonest causes of hypercalcemia in the outpatient setting with a prevalence of ~0.1-0.2%. In most patients calcium elevation is fortuitously detected during routine blood chemistry analysis. Most (≥80%) of these patients have a solitary adenoma, with the reminder having multi-glandular hyperplasia. Surgical removal of the abnormal gland (s) is the treatment of choice for permanent cure. The traditional surgical approach involves full cervical exploration with identification of all four glands. Localized or minimally invasive surgery relies on localization techniques such as Technetium 99 Sestamibi. We performed high resolution ultrasound (US, 10 Mhz) as the primary modality of localization along with fine needle aspiration biopsy or as a complementary test to Sestamibi scans. The operator was blinded to the result of prior localization if any had been performed. 17 patients were subjected to US examination of the neck, 7 of whom also underwent Sestamibi scans. Average age was 54 years (10 females and 7 males), serum calcium 10.9Ϯ0.08 mg /dl, and serum PTH 123Ϯ12.9 pg/ml. A possible parathyroid adenoma was found by US in all of the subjects, with a calculated volume of 1.037Ϯ0.3cm 3 . Fine needle biopsy syringe washings on these adenomas had a PTH level of 19,959Ϯ7948pg/ml. We also analyzed PTH syringe washings of thyroid nodules that co-existed in patients (n=12) and the average was 11.25Ϯ2.5pg/ml, significantly different (p≤0.0001) from the parathyroid washings. A solitary adenoma was found on US examination in 15/17 subjects, and in all cases the localization was confirmed in the course of minimally invasive surgery. Successful removal was confirmed by a ≥50% fall in the intra-operative PTH level after removal of the identified gland. All patients remain normocalcemic several months after surgery. Two subjects had multiglandular hyperplasia detected by lack of intra-operative PTH fall, these patients underwent four gland explorations. Of the 7 subjects who had also had Sestamibi scans, four of the scans had been negative and one was a false positive as judged by the surgical results. There was no relationship of the level of elevation of PTH in the syringe washing specimen to the volume of the parathyroid gland, serum PTH level, serum calcium level or age of patients. We conclude that cervical US localization of parathyroid adenomas, confirmed by PTH estimation in fine needle aspirates of the adenoma, is an accurate localization technique that is far superior to Sestamibi scanning and allows minimally invasive surgery in most subjects with primary hyperparathyroidism.