There are several specific issues that significantly affect the anesthetic management for patients undergoing thyroid surgery. In addition to the general considerations pertaining to anesthesia, specific attention should be directed to the assessment of thyroid function, the size and location of the thyroid gland, its relationship to the trachea and adjacent vascular structures, and the co-existence of a multiple endocrine neoplasia. Hyperparathyroidism due to an adenoma or hyperplasia is the most common presenting symptom of multiple endocrine neoplasia 1 syndrome. Patients at risk of iatrogenic hypoparathyroidism should have ionized calcium levels monitored postoperatively until calcium levels demonstrate that parathyroid function is intact. Primary hyperparathyroidism may result from benign parathyroid adenoma, multiple gland hyperplasia and carcinoma of the parathyroid glands. Clinical signs include carpopedal spasm during cuff inflation, facial twitching by tapping over the facial nerve at the parotid gland, and a prolonged QT interval on the ECG.