Post-thyroidectomy permanent hypocalcemia and hypoparathyroidism: frequency and risk factors

Abstract

Background: Hypoparathyroidism is the most common complication after thyroidectomy and the main reason for frequent outpatients' visits; however, there is a poor understanding of its outcomes, and no clear follow-up strategies are available. We aimed to evaluate the frequency and risk factors of post-thyroidectomy hypocalcemia hypoparathyroidism in Libyan patients. Methods: A case series study was conducted. The serum calcium and parathyroid hormone level (PTH) were measured at least 8 months post thyroidectomy. Results: 124 patients were reviewed in this study; 19 (15.3 %) were males and 105 (84.7 %) were females. 30.6 % of males and 13.7% of females developed hypocalcemia and hypoparathyroidism. Total thyroidectomy (TT) was performed in 62.9 % of all patients, while 24.2% of all patients underwent near total thyroidectomy (NTT). 12.1% of all patients underwent bilateral subtotal thyroidectomy (BST) and 1 patient underwent hemi thyroidectomy (0.8%). The risk of hypocalcemia was higher in patients with malignant thyroid disease in comparison to benign thyroids (45.8 % vs. 27% of patients). Papillary thyroid carcinoma (PTC) was the most common cause of both hypocalcemia and hypoparathyroidism (45.5% for both) followed by Graves' disease (22.2% and 14.8% for hypocalcemia and hypoparathyroidism respectively). Hypocalcemia and hypoparathyroidism were more frequent in patients who underwent TT (19.2%), as compared to patients who underwent NTT (6.6 %). Among nine patients who were operated on twice, three patients had hypocalcemia, and two of them were found to be hypoparathyroid; one case is diagnosed with Graves' disease, while the other was diagnosed as PTC. Conclusion: Total thyroidectomy, and re-operation are associated with increased prevalence of permanent hypocalcemia and hypoparathyroidism when compared to less extensive thyroid resection modes.