Change in parathyroid hormone levels from baseline predicts hypocalcemia following total or completion thyroidectomy.

BACKGROUND: This study aims to identify the strongest predictor of postoperative hypocalcemia following thyroid surgery. METHODS: Study of patients who underwent total/completion thyroidectomy. No patients received postoperative calcium supplementation. Demographic and perioperative data were collected including preoperative baseline parathyroid hormone (PTH) levels, PTH levels at 30 min and 6 h post-excision, and 18 h post-excision calcium levels. RESULTS: Of 124 patients studied, 20.2% developed temporary hypocalcemia (Ca <8.5 mg/dL at 18 h post-excision). In multivariate analyses, absolute PTH levels at 30 min and 6 h post-excision as well as change in PTH from baseline at 30 min and 6 h post-excision were statistically significantly associated with postoperative hypocalcemia. Per 10 units decrease in PTH from baseline at 30 min post-excision, the risk of developing temporary hypocalcemia increases by 17%. CONCLUSION: Absolute PTH levels and change in PTH from baseline at 30 min and 6 h post-excision predict hypocalcemia after total or completion thyroidectomy.

ECTOPIC THYROID TISSUE MASQUERADING AS A FUNCTIONAL CAROTID BODY PARAGANGLIOMA.

OBJECTIVE: Ectopic thyroid tissue (ETT) is a rare entity resulting from thyroid gland dysembryogenesis. We present a case of ETT confirmed by histopathology that was misdiagnosed clinically as a carotid body tumor. METHODS: A 34-year-old female with a history of thyroidectomy for a goiter presented with 1 year of worsening tachycardia (heart rate ranging from 82 to 111 beats per minute), anxiety, hot flashes, and intolerance to heat. For further evaluation, we obtained imaging of her neck, including a thyroid ultrasound, a computed tomography (CT) scan, and an octreotide scan. We also performed laboratory studies including fractionated 24-hour urine meta-nephrines and thyroid function tests. RESULTS: Her thyroid ultrasound showed a mass at the right carotid bifurcation, which was confirmed on CT as well as on an octreotide scan. Her free thyroxine was 0.6 ng/dL (normal, 0.7 to 1.5 ng/dL) and her thyroid-stimulating hormone was 4.51 mIU/L (normal, 0.45 to 4.5 mIU/L). Her fractionated 24-hour total urine metanephrines were 1,502 mcg/24-hour (normal, 149 to 535 mcg/24-hour). She underwent resection of a vascular mass from the carotid bifurcation. Histologic examination revealed ETT with dilated follicles filled with colloid with no evidence of paraganglioma/carotid body tumor. CONCLUSION: The somatostatin receptor is typically present in paragangliomas; however, there are reports of octreotide uptake within thyroid goiters. It has been demonstrated that psychoactive medications can increase urine metanephrines. Given the patient's psychiatric history and that no other tumors were identified on imaging, it was felt that the elevated urine normetanephrine in this case was most likely due to psychoactive medication use. This case demonstrates the preoperative imaging findings and postoperative pathologic confirmation of an unusual presentation of ETT.