Factors Contributing to Post-Operative Hypocalcaemia After Total Thyroidectomyexperience in a Tertiary Care Govt. Hospital in Eastern India

Abstract

BACKGROUND Postoperative hypocalcaemia is a common complication after total thyroidectomy but most often it is transient. Although these are mostly amenable to calcium and vitamin D supplementation, symptomatic patients sometimes need prolonged hospitalization following thyroid surgery, leading to increased healthcare costs. In the present study, we tried to find out factors which can predict the occurrence of post-operative hypocalcaemia & hypoparathyroidism in total thyroidectomy patients, facilitating their early detection and institution of definitive management in time, preventing emergency admissions & catastrophes. METHODS A prospective observational study was carried out in the Department of ENT & Head-Neck Surgery of a tertiary care govt. hospital in eastern India. Patients who underwent total thyroidectomy for multinodular goitre (MNG) and adenomatoid goitre (AG) or total/completion thyroidectomy for well differentiated thyroid carcinomas (WDTC), in the age group of 20-55 years were included in our study. We recorded the following parameters: Age, gender distribution of cases, type of operation, pre-operative Fine Needle Aspiration Cytology (FNAC) status, size of thyroid nodule operated (based on pre-operative ultrasonographic study), number of parathyroid glands preserved during operation, pre-operative vitamin D levels, post-operative serum calcium levels at 6 hours & 12 hours (positive i.e. increasing slope & non-positive i.e. decreasing/non-changing slope), early post-operative serum iPTH levels (at 6 hours), development of symptomatic hypocalcaemia-transient or permanent. RESULTS In the present study we measured serum calcium level 6 hours & 12 hours post-operatively. It has been found that patients with serum calcium levels on positive slope have lesser chances of occurrence of symptomatic hypocalcaemia & permanent hypocalcaemia than those on non-positive slope. We found that patients having serum iPTH level between 15-65 pg/ml showed lesser propensity to develop hypocalcaemia in comparison with those with serum iPTH level <15 pg/ml. In our study, it has been found that all the 3 cases who developed permanent hypocalcaemia were suffering from vitamin D deficiency; whereas, patients with normal vitamin D levels posed lesser risk of developing significant hypocalcaemia. In our observation, patients with only two parathyroid glands identified per-operatively have more chances of developing hypocalcaemia & those in whom all four parathyroid glands were preserved, very low risk of hypocalcaemia is associated. Furthermore, preservation of functional parathyroid gland with intact blood supply is found to be of immense importance than mere identification of the glands. In our series, it has been noted that with increase in the size of thyroid nodule, chances of hypocalcaemia increases. Patients undergoing complete thyroidectomy for histopathological report of WDTC in a previously benign (based on pre-operative FNAC) thyroid nodule, increased chances of development of post-operative hypocalcaemia. CONCLUSI...