title: A rising ioPTH level immediately after parathyroid resection: are additional hyperfunctioning glands always present? An application of the Wisconsin Criteria.
abstract: OBJECTIVE
  This study was designed to determine if a rising intraoperative parathyroid hormone (ioPTH) level following parathyroid resection indicates multiple hyperfunctioning glands and to determine the appropriate intraoperative management.
  
  
  BACKGROUND
  IoPTH monitoring is commonly used to guide parathyroid surgery. A significant rise in the ioPTH immediately after resection of a single parathyroid is often perceived to be indicative of the presence of additional hyperfunctioning glands.
  
  
  METHODS
  A total of 797 consecutive patients underwent parathyroidectomy for primary hyperparathyroidism with ioPTH monitoring. Patients with an elevated 5 minute ioPTH were extensively studied. Operative success was defined as normocalcemia 6 months after surgery.
  
  
  RESULTS
  Of the 797 patients, 108 (14%) had a rising ioPTH 5 minutes after resection of a single parathyroid. Of these 108 patients, 36 (33%) continued to have elevated ioPTH levels and further exploration revealed additional hyperfunctioning glands. Importantly, in the majority of patients (n = 72 or 67%), the ioPTH started to fall after an additional 5 minutes (10 minutes after resection). The ioPTH declined by more than 50% from the 5 minute elevated value in 30%, 89%, and 99% of patients at 10, 15, and 20 minutes after resection, respectively. Importantly, this fall correctly predicted operative success in 100% of patients after removal of a single abnormal gland.
  
  
  CONCLUSIONS
  A rising ioPTH level immediately after parathyroidectomy is observed in 14% of patients. The majority of these patients do not have additional hyperfunctioning glands. Most of patients fell below 50% of the 5 minute elevated value within 20 minutes of gland resection and in all cases this fall correctly predicted operative success.
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin, Madison, WI 53792-7375, USA.
authors.forename: Mackenzie R
authors.initials: MR
authors.lastname: Cook
authors.forename: Susan C
authors.initials: SC
authors.lastname: Pitt
authors.forename: Sarah
authors.initials: S
authors.lastname: Schaefer
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sippel
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood; D002648:Child; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D002118:Calcium