Background:

Hypocalcaemia and hypoparathyroidism are common complications following thyroidectomy. However, their incidence varies widely in the literature and their risk factors are not well established.

Methods:

Thirty-five patients that had a thyroidectomy between June and November 2012 were identified prospectively. Hypocalcaemia was defined as a value of less than 7.5 meq/L of seric calcium in the first day after surgery without symptoms or of less than 8.5 meq/L with symptoms or signs associated with hypocalcaemia. Hypoparathyroidism was defined as a value of less than 8.5 meq/L of seric calcium 12 months after surgery and/or the need of calcium and vitamin D suplementation. Additional variables evaluated were age, sex, history of thyroid surgery, days at the hospital after surgery and main surgeon of the procedure.

Results:

Overall, 14 (42.4%) out of 35 patients who underwent thyroidectomy developed hypocalcaemia and 8 (22.8%) suffered from hypoparathyroidism. Total thyroidectomy resulted in a higher incidence (50%) of hypocalcaemia and hypoparathyroidism (28.6) when compared with unilateral thyroid lobectomy. Additional factors significantly associated with postoperative hypocalcaemia and hypoparathyroidism included pre-operative malignant cytology (p = 0.014; p= 0.044), cervical lymphadenectomy (p = 0.024; p = 0.033) and a consultant as main surgeon (p = 0.030; p = 0.027). Hypocalcaemia following thyroidectomy resulted in 4.9 days of extended hospital stay (8.0 versus 3.1 days p = 0.018).

Conclusion:

Hypocalcaemia and hypoparathyroidism are frequent complications of thyroidectomy, particularly total thyroidectomy associated with cancer or cervical lymphadenectomy or performed by a specialized physician as main surgeon.