The effect of preoperative calcitriol prophylaxis on post-thyroidectomy hypocalcaemia in children

Lisanne Vendrig; Christiaan Mooij; Joep Derikx; Paul van Trotsenburg; Nitash Zwaveling-Soonawala

Background: Transient or permanent hypoparathyroidism is one of the most well-known complications of total thyroidectomy and may lead to symptomatic hypocalcaemia. Treatment of post-thyroidectomy hypocalcaemia usually consists of postoperative calcium and/or vitamin D supplementation. In 2013 we implemented prophylactic pre-thyroidectomy calcitriol supplementation for all children undergoing total thyroidectomy at Amsterdam UMC. The objective of this study was to evaluate the efficacy of this prophylactic calcitriol supplementation in preventing post-thyroidectomy hypocalcaemia in children.

Methods: In a retrospective case study we included all children (age < 18 years), who underwent a (sub)total or completion thyroidectomy in Amsterdam UMC, between 2000 and 2020. Patients were divided into two groups, patients with preoperative calcitriol supplementation, and those without (controls). Hypocalcaemia was defined as total serum calcium concentration of < 2.0 mmol/l. Primary outcome measure was the occurrence of hypocalcaemia in the first 72 hours after surgery. Secondary outcome measures were occurrence of symptomatic hypocalcaemia, need for medical intervention for hypocalcaemia and length of hospitalization.

Results: A total of 51 patients were included; 26 with calcitriol prophylaxis and 25 controls. There was no significant difference in occurrence of hypocalcaemia (17/26 prophylaxis group; 18/25 control group). Median post-operative calcium concentrations in the first 72 hours were significantly higher in the group with prophylaxis at 12-17 hours after surgery (2.12 vs 1.96 mmol/l), 30-35 hours (2.26 vs 2.01 mmol/l) and 36-41 hours (2.17 vs 1.92 mmol/l). Occurrence of symptomatic hypocalcaemia, need for medical intervention and length of hospitalization were not significantly different between the groups (Table).

Table: Hypocalcaemia outcome of 51 pediatric thyroidectomy cases.
	Calcitriol prophylaxis (n = 26)	Controls (n = 25)	P-value
Age at surgery in years (median, range)	14 (3-17)	13 (1-17)	0.828
Indication for surgery
Prophylactic	2	6	0.276
Benign disease	13	9
Malignant disease	11	10
Extent of surgeryNo lymph node dissection Central lymph node dissectionCentral+lateral lymph node dissectionNode picking	18440	18322	0.564
Hypocalcaemia < 72 hours	17	18	0.764
Symptomatic hypocalcaemia < 72 hours	6/17 1 not reported	5/18 2 not reported	1.000
Permanent hypocalcaemia	5	9	0.305
Length of hospitalization in days (median, range)	3 (2-8)	3 (2-10)	0.356

Conclusion: While calcitriol prophylaxis resulted in somewhat higher postoperative calcium concentrations, it did not reduce the occurrence of hypocalcaemia and did not affect clinical outcome measures such as occurrence of symptomatic hypocalcaemia and length of postoperative hospitalization.

ESPE Abstracts

P1-91