Significant clinical differences in primary hyperparathyroidism between patients with and those without concomitant thyroid disease.

PURPOSE: We evaluated the differences in diagnosis and treatment for primary hyperparathyroidism (pHPT) in patients with and those without concomitant thyroid disease.
METHODS: One hundred and ten patients with pHPT underwent parathyroid localization and thyroid examination by ultrasonography (US) and sestamibi scintigraphy (MIBI). The clinical and biochemical findings, parathyroid localization, and operations performed were compared in 49 patients without thyroid disease and 61 patients with thyroid disease.
RESULTS: Asymptomatic hypercalcemia was significantly more prevalent in patients with concomitant thyroid disease (88.5%) than in those without thyroid disease (49.0%) (P < 0.01). The mean serum calcium was significantly higher and the inorganic phosphate level was significantly lower in patients without concomitant thyroid disease than in those with concomitant thyroid disease (P < 0.05, P < 0.01, respectively). The pathologic parathyroid gland was identified significantly more often in patients without concomitant thyroid disease than in those with concomitant thyroid disease both by US and MIBI (P < 0.05). Unilateral exploration was performed more often in patients without thyroid disease than in those with thyroid disease (P < 0.01).
CONCLUSION: Primary hyperparathyroidism was diagnosed at an earlier stage in patients with concomitant thyroid disease. Thyroid disease concomitant with pHPT influenced parathyroid localization as well as the indication for minimally invasive parathyroidectomy.