The need to give calcium supplementation after total thyroidectomy.

INTRODUCTION

Hypocalcemia may occur secondary to total thyroidectomy due to surgical trauma, devascularization, unintentional removal of parathyroid glands, and reoperation. Other causative mechanisms that have been implicated in the pathophysiology of post-thyroidectomy hypocalcaemia include calcium uptake by the bone in patients with thyrotoxic osteodystrophy, increased release of calcitonin as a result of thyroid manipulation.¹  

Postoperative hypocalcaemia is more common after total thyroidectomy than after other types of thyroidectomies.² It usually manifests itself in the first 24 hours post operatively or within the 2-3days after operation, however, very rarely the onset is delayed 2-3 weeks.³ Hypocalcemia may be transient, resolving within a few months, or permanent, requiring lifelong oral calcium and vitamin D supplementation.⁴ In most patients it is transient that

resolves spontaneously and only few patients develop permanent hypocalcaemia.⁵

Serum calcium is distributed among three forms (protein bound 40%, complexed to phosphate and other anions 10% and ionized 50%.⁶ The first clinical sign of hypocalcaemia may be less typical and may include numbness and tingling sensation around the

mouth and extremities.⁷ Tetany, which is characterized by carpopedal spasm, laryngeal stridor and tonic-clonic seizures may occur.6

Intravenous calcium gluconate should be given 10-20 ml of 10% solution slowly until the symptoms disappear, then 50 ml of 10% calcium gluconate can be added to 500 ml of 5% dextrose solution and administered by intravenous drip at a rate of 1 ml/kg/h.8 Routine oral calcium and vitamin D supplements have been proposed to prevent the development of symptomatic hypocalcemia and to increase the likelihood of early hospital discharge after bilateral surgical treatment of the thyroid gland‎9.⁸

PATIENT AND METHODS

Accepted patients had been diagnosed as different thyroid diseases other than cancer and had bilateral total thyroidectomy done. Patients enrolled were females with no limitation for age. Acceptance also included within normal renal and hepatic profile and adequate thyroid profile. Patients were excluded if parathyroid mass was found during total thyroidectomy or thyroid cancer; previous neck surgery or radiation therapy; or prior calcium and/or vitamin D intake.

This prospective study was carried on 90 patients who had total thyroidectomy surgery done for various thyroid diseases at the department of surgery –Oum Al Masryeen General Hospital and Al-Azhar University Hospitals in the period between 2017-2020. The study protocol was approved by the Ethical committee and an informed consent was taken from every patient. Accepted participants were assigned in a random way in a 1:1 ratio to receive calcium and vitamin D (routine calcium supplemented group) or without supplementation (control group).

The present study main end point is to evaluate the need to give routine calcium supplements post-operatively to patients who had done total thyroidectomy, as assessed by the occurrence of symptomatic hypocalcemia for 3 months after surgery.

Patients in the routine calcium group received oral calcium and vit D supplementations from first postoperative day for two weeks, whereas patients received no supplementation in the control group. Serum calcium levels were followed up in the postoperative period for three months. If symptomatic hypocalcemia occured in any of the two groups intravenous calcium tobe given followed by oral calcium supplements.

Analysis of data was done by IBM computer using SPSS (statistical program for social science version 21) as follows:

Description of quantitative variables as mean, SD and median and IQR. Description of qualitative variables as number and percentage. We used Chi-square test to compare qualitative variables between groups. Fisher exact test was used instead when one expected cells are less than 5. MannWhitneytest was used instead of unpaired t-test in non-parametric data (SD>30%mean). Wilcoxontestusedtest was used instead of paired t-test in non-parametric data (SD>30%mean). P≤0.05 significant and P

This study included 90 patients who underwent total thyroidectomy due to different thyroid diseases. The preoperative serum calcium level was measured and was found to be normal in all cases. The postoperative serum calcium was measured three months postoperative.

RESULTS

The present study includes 90 patients with ages range from 21 to 84 divided into two groups based on whether they were on calcium supplementation or not. 100% of patients were females. There was no statistical significance of age in relation to serum Ca level as P value  table (1).

Table 1: Shows age in relation to need of calcium supplementation and its statistical insignificance.

The majority of patients (69, 76.66%) had multinodular goiter. On the other hand only 21 patients with percentage 23.33% had other thyroid pathologies including Hashimoto’s thyroiditis and Diffuse Thyroid Goiter. No statistical significance of the relation between the different clinic-pathological diagnosis and the serum Ca level post-operative as P value > 0.05, table (2).

Table 2: Shows number and percentage of patients with different clinic-pathological diagnosis and its insignificance to serum calcium post-operative.

The time needed for total thyroidectomy in both groups which is almost the same. This means there’s no statistical significance of relation between time consumed in surgery and serum Ca level with P value > 0.05, table (3).

Table 3: Shows the Relation between the Time of surgery in both groups and its insignificance to serum calcium post-operative.

Study shows improvement in the level of serum calcium in the group already on supplementation. On the other hand it shows slight decrease in serum calcium level in the group without supplementation. The statistical analysis showed highly significant relationship between the Ca supplementation and hypocalcemia with P value of less than 0.05; that serum calcium level post-operative in the routine calcium group demonstrate increase in the serum level of calcium with Mean± SD (8.51±0.33).On the other hand serum calcium level post-operative in the control group demonstrate decrease in the serum level of calcium with Mean± SD (6.88±0.92) Figures (1-2) Tables (4-6).

Table 4: Shows the significant relation between follow-up serum Ca levels in both groups.

Table 5: Shows the significant relation between calcium supplementation and increase in Ca serum levels post-operatively.

Table 6: Shows the significant relation between Non calcium supplementation and decrease in Ca serum levels post-operatively.

The majority of patients in both groups are not hypertensive with percentage (73.3%) while the percentage of patients with hypertension and/or IHD ranges from (20-26.7%). This statistical analysis is not significant as P value . Also the majority of patients in both groups are not diabetics with percentage (80%) while the percentage of patients with Diabetes (20%). This statistical analysis is not significant as P value > 0.05. Socollectively no significant relationship between diabetes and hypertension to postoperative hypocalcemia, tables (7-8).

Table 7:  Shows the insignificant relation of Hypertension and IHD in both groups to post-operative hypocalcemia.

Table 8: shows the insignificant relation of Diabetes in both groups to post-operative hypocalcemia.