title: Prospective study of perioperative factors predicting hypocalcemia after thyroid and parathyroid surgery.
abstract: OBJECTIVE
  To identify whether perioperative 1,25-dihydroxyvitamin D or parathyroid hormone (PTH) levels will predict the development of hypocalcemia after thyroid and parathyroid surgery.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  The study included 103 patients who underwent thyroid or parathyroid surgery between 2002 and 2004, with a comparison of the patients who underwent thyroid lobectomy (TL; n = 34), total thyroidectomy (TT; n = 27), parathyroid adenoma excision (PAE; n = 34), and subtotal parathyroidectomy for hyperplasia (SP; n = 8).
  
  
  METHODS
  Preoperative 1,25-dihydroxyvitamin D levels, number of patients requiring calcium replacement, and postoperative PTH and calcium levels.
  
  
  RESULTS
  No patients in the TL or PAE group developed postoperative hypocalcemia that required calcium replacement. Six patients (22%) in the TT group and 3 patients (38%) in the SP group required calcium replacement for clinically significant hypocalcemia (P<.001). All patients who required calcium replacement had PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery. Among the patients with postoperative PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery, no patients in the PAE group required calcium replacement, compared with 75% of patients in the TT and SP groups (P<.001). The patients in the TT group had significantly lower postoperative calcium levels than those in the TL (P<.001) or the PAE (P<.005) group. The patients in the TL group reached stable calcium levels significantly earlier than those in the other groups (15.8 hours after surgery; P<.05). There was no relationship between preoperative 1,25-dihydroxyvitamin D levels and postoperative calcium levels.
  
  
  CONCLUSIONS
  Preoperative 1,25-dihydroxyvitamin D levels were not predictive of postoperative calcium levels. Patients who undergo PAE or TL are at extremely low risk for requiring calcium replacement. Patients who undergo TT or SP with 8-hour postoperative PTH levels greater than or equal to 15 pg/mL (1.6 pmol/L) are at low risk for developing postoperative hypocalcemia, whereas those with PTH levels less than 15 pg/mL (1.6 pmol/L) have a high risk of developing hypocalcemia.
authors.affiliation: Division of Head and Neck Surgery, University of California-San Diego, USA.
authors.forename: Stanley H
authors.initials: SH
authors.lastname: Chia
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weisman
authors.forename: David
authors.initials: D
authors.lastname: Tieu
authors.forename: Colleen
authors.initials: C
authors.lastname: Kelly
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Dillmann
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Orloff
mesh_terms: D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood; D005500:Follow-Up Studies; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000209:etiology*; D010279:Parathyroid Diseases / Q000097:blood / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy / Q000009:adverse effects*; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013959:Thyroid Diseases / Q000097:blood / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D002118:Calcium