Remission of non-insulin-dependent diabetes mellitus following resection of a parathyroid adenoma

A 56-year-old woman presented with diabetes mellitus and primary hyperparathyroidism simultaneously. Initial random blood glucose was recorded at 20.8 mmol l(-1), serum calcium was 3.07 mmol l(-1) (normal range 2.10-2.55 mmol l(-1)), and plasma parathyroid hormone estimation by intact assay was 110 ng l(-1) (normal range 10-65 ng l(-1)). Initial glycated haemoglobin was 9.4% (non-diabetic range <7.5 %). Left lower parathyroidectomy was carried out and pathology confirmed the presence of a chief cell adenoma. The gland measured 10 x 5 x 5 mm. Following parathyroidectomy serum calcium normalized, glucose tolerance improved, and a subsequent 75 g oral glucose tolerance test was normal. The patient weighed 80 kg at presentation but the post-operative weight had risen to 81.5 kg. The most recent glycated haemoglobin was 4.6 %. Primary hyperparathyroidism may have a reversible effect on glucose tolerance.