Parathyroid Hormone as a Predictor for Calcium Replacement after Total or Completion Thyroidectomy

Abstract

Objectives: 1) Analyze whether postoperative parathyroid hormone (PTH) level predicts the need for calcium replacement treatment after total or completion thyroidectomy. 2) Evaluate our calcium replacement regimen that is based on PTH levels. Methods: Prospective data collected between April 2010 and April 2011. Study Population :Patients undergoing a total or completion thyroidectomy (n = 40). All patients had calcium (Ca2+) checked at 2200h on day 0 (D0), day 1 (D1), day 3 (D3), and day 6 or onwards (D6+). PTH levels were checked on D1, D3, and D6+. Patients with Ca2+ < 1.95 on D1 were given Calcichew (2 tablets) and 1 microgram 1-alphacalcidol. On D1, patients with PTH > 1.5 and calcium > 1.95 were discharged with no supplementation, and patients with PTH < 1.5 were started on a calcium supplementation regimen depending on their D1 calcium level. –Twenty-nine patients had PTH > 1.5 on D1; none had calcium < 1.95 on D0 or D1, 12 had calcium < 2.2 on D0, 9 had calcium < 2.2 but > 1.95 on D1, and 1 patient became normocalcaemic. Thus 68.9% (n = 20) had calcium < 2.2 but > 1.95 by D1. Ten patients (34.8%) had calcium < 2.2 but > 1.95 on D6+. Eleven patients were started on a calcium replacement regimen on D1, as their PTH was < 1.5. Conclusion: PTH level is a good predictor for the need for calcium replacement after total or completion thyroidectomy, as the patient’s calcium levels do not fall to a level that requires treatment if PTH > 1.5 on D1.