Endocrine Abstracts

Most patients with vitamin D deficiency and osteomalacia have elevated parathyroid levels with normal or low serum calciums .This hyperparathyroidism is described as secondary hyperparathyroidism and resolves with correction of vitamin deficiency. We describe three cases where there was coexistant osteomalacia vitamin D deficiency, elevated parathyroid hormone and hypercalcaemia.

Case 1

A 40 year old Asian female presented with a six month history of bone pain. She had a waddling gait. Investigations revealed calcium 2.83mmol/l and alkaline phosphatase 779 IU/l, PTH 668 ng/l (12-72), 25-hydroxy Vitamin D was undetectable. Radiographs showed generalised osteopaenia and hyperparathyroid bone disease.

She was commenced of Ergocalciferol and her calcium rose to 3.04 mmol/l. The PTH level remained elevated after 3 months. She had a parathyroidectomy. At histology there was evivdence of an underlying parathyroid carcinoma.

Case 2

A 41 year old Asian lady was complaining of pain in her right hand and forearm. She had a calcium of 2.76 mmol/l. PTH was 19.1 IU/l (1.05-6.84) and an undetectable 25-hydroxy vitamin D. She has been commenced on Ergocalciferol, and is now pregnant.

Case 3

A 64 year old lady of Asian origin was found to have a calcium of 2.80 mmol/l, PTH 67 pg/ml (10-65) and the 25-hydroxy Vitamin D of 9 ng/ml (10-68).

Discussion

The hypercalcaemia in these cases would usually be regarded as due to primary hyperparathyroidism with co-existent Vitamin D deficiency. We hypothesize that where the vitamin D deficiency with osteomalacia is long standing, as it may be in patients of Asian origin, the hyperparathyroidism may be better described as tertiary. Furthermore in case 1 osteomalacia may have been a risk factor for parathyroid carcinoma.