Endocrine Abstracts

Cinacalcet, a calcimimetic, is licensed for the management of primary hyperparathyroidism (PHP) where surgery is deemed inappropriate. It is unclear when patients might be deemed more appropriately managed by medical treatment rather than surgery. We report two cases in which cinacalcet has been used to predict the effect of parathyroidectomy and a choice to be made between surgery and conservative management.

A 43-year-old woman had a parathyroid adenoma removed 12 years previously. Subsequently there was a gradual increase in her plasma calcium and the development of tiredness and malaise. There was little doubt of the diagnosis of PHP (Ca 2.7–2.8 mmol/l, PTH 62–95 pg/ml). Sestamibi scintigraphy suggested the presence of a right lower parathyroid lesion. She was reluctant to undergo repeat neck exploration because of the increased risk of vocal cord damage and was given cinacalcet to see if normalisation of her plasma calcium would improvement her symptoms. She became normocalcaemic (Ca 2.31 mmol/l) and her symptoms vanished within a few days. In view of this she was happy for further neck exploration.

A 65-year-old man was admitted with ischaemic heart disease. He had Addison’s disease and was on adequate replacement therapy. His calcium was elevated (2.6–2.8) with elevated PTH (73–87). There was no evidence of end organ damage but he suffered non-specific abdominal pain twice a week. To determine whether hypercalcaemia was responsible for his pain he was commenced on cinacalcet. On this plasma calcium and PTH normalised and his pain has settled. Hence, despite his co-morbidities the benefits of parathyroidectomy are likely to outweigh the risks.

These cases illustrate how short term use of cinacalcet may be of use to determine the relationship of non-specific symptoms to plasma calcium levels and thus make an informed decision about the possible benefits of response to parathyroidectomy in these patients when there may be some reluctance to undergo surgery. A randomised controlled trial of such patients is desirable.