Endocrine Abstracts

Primary hyperparathyroidism is a rather frequent disorder characterized by high plasma PTH and calcium. Vitamin D deficiency is prevalent in all areas of the world. Vitamin D deficiency has been described in patients with primary hyperparathyroidism. When present, vitamin D deficiency may be associated with large size parathyroid adenomas and musculoskeletal pain.

The aim was to describe two cases of primary hyperparathyroidism and vitamin D deficiency.

A patient, male aged 87 years, was hospitalized for coronary insufficiency and diffuse musculoskeletal pain. During hospitalization high plasma calcium was observed, calcium levels being 10.5 mg/dl. Laboratory investigations revealed high plasma parathyroid hormone levels, PTH being 117 pg/ml (normal values 10–65 pg/ml) and low plasma 25(OH)D₃ levels, 25(OH)D₃ being 8 ng/ml (normal values <30 ng/ml). Bone mineral density was measured in the neck of the left femur and revealed a T-score of −3.05. Vitamin D supplementation was initiated followed by the administration of alendronate. Ultrasonography revealed an adenoma beneath the right lobe of the thyroid gland. Conservative management was chosen due to old age. A patient, female aged 42 years, presented with diffuse musculoskeletal pain. Laboratory investigations revealed high plasma PTH (PTH 163 pg/ml), low plasma 25(OH)D₃ (25(OH)D₃ 9 ng/ml) and calcium 11.3 mg/dl. On scintigraphy a parathyroid adenoma was visualized beneath the left lobe of the thyroid gland. Vitamin D supplementation was performed followed by surgery to remove the parathyroid adenoma. Postoperatively, the patient developed hungry bone syndrome. In both cases after vitamin D supplementation the diffuse musculoskeletal symptoms improved.

Conclusions: Vitamin D deficiency may be found in the context of primary hyperparathyroidism. When present, vitamin D supplementation should be initiated cautiously, as it may aggravate primary hyperparathyroidism. Cautious vitamin D supplementation is however necessary, will not cause an increase in calcium and PTH levels and will improve musculoskeletal pain.