Intraoperative parathyroid hormone (PTH) testing in patients with primary hyperparathyroidism and PTH levels in the normal range

Abstract

Background: Primary hyperparathyroidism is a common endocrine disorder. Hypercalcemia with normal PTH levels is very unusual and can lead to diagnostic difficulties. There are very few very few studies in the literature and all with limited numerical samples. The goal of the present study was to determine the real incidence and characteristics of primary hyperparathyroidism with normal PTH and to evaluate if intraoperative PTH testing is useful in these patients. Methods: We performed a retrospective review of 314 patients who had undergone parathyroidectomy to treat primary hyperparathyroidism between January 2002 and December 2016. Patients were divided in two groups according to biochemical preoperative findings: in Group A were included patients with normal serum PTH, in Group B those with increased serum PTH. Results: Nine patients (3.7%) were included in group A and 235 in group B. Patients in group A were younger (51. 5 ± 12.9 years vs 59.6 ± 12.5); preoperative serum calcium and the incidence of coexisting thyroid disease were similar between the two groups. Symptomatic patients were more frequent in Group A (77.8% vs 39.1%; p = 0.048). There were no significant differences regarding preoperative localization studies and surgical procedure. Intraoperative PTH determination demonstrated sensitivity of 86% in group A and 97% in group B, specificity and positive predictive value of 100% in both the groups, negative predictive value of 67% in group A and 79% in group B. Histopathological examination demonstrated a single gland disease in 8 (88.9%) patients in group A and a multi gland disease in 1 (11.1%), in group B single gland disease was found in 218 (92.8%) patients and multi gland disease in 17 (7.2%). Unsuccessful surgery with persistent or recurrent hyperparathyroidism occurred in 1 (11.1%) patient in group A and 4 (1.7%) in group B. Conclusions: Primary hyperparathyroidism with normal PTH is rare but physicians should be aware of this possibility in patients with hypercalcaemia. Patients with normal PTH levels are younger and more frequently symptomatic. Intraoperative PTH testing plays an important role in the operative management even in such patients.

The coexistence of hypercalcemia, osteoporosis and thymic enlargement in graves’ disease: a case report

“…The parathyroid hormone (PTH) was low (3.16 ng/L, normal range: 15-65 pg/ml). Primary hyperparathyroidism with normal or low PTH has been reported although they are relatively rare [9,10], so we performed a 99mTc-MIBI scintigraphy to exclude this diagnosis. 99mTc-MIBI scintigraphy didn't show the accumulation of radiotracer uptake in parathyroid and other parts of the body, thus primary and ectopic hyperparathyroidism was excluded.…”

A Parathyroid Cancer With Soporous State, Depression and Severe Cognitive Decline in Acute Renal Failure

“…Surgical excision is the cardinal treatment. The use of intraoperative PTH (IOPTH) testing is debated: according to Medas F. et al [14] it plays an important role, especially in patients with pHPT and normal PTH level. Instead, Sartori P.V.…”

A parathyroid cancer with soporous state, depression, and severe cognitive decline in acute renal failure

“…1,2,12,13 Surgical excision is the cardinal treatment. The use of intraoperative PTH (IOPTH) testing is debated: according to Medas et al 14 it plays an important role, especially in patients with pHPT and normal PTH level. Instead, Sartori et al 15 strongly suggest reconsidering the role of IOPTH monitoring during parathyroidectomy in patients with concordant preoperative ultrasonography and nuclear scanning.…”