Endocrine Abstracts

A previously fit and well 49-year-old gentleman presented to hospital with vomiting and myalgia. Three weeks previously he had been admitted with acute pancreatitis, but no cause was found. An incidental hypercalcaemia was also noted at that time. He had lost approximately two stone in weight in the previous three months and had become more short of breath on exertion. He had a strong family history for type I diabetes mellitus, but otherwise there was no significant history.

On this admission he was found to have a high corrected calcium of 3.14, with a low parathyroid hormone (<0.3). Further tests revealed that he had a low vitamin D, a normal myeloma screen, PSA and serum ACE. Imaging performed was unremarkable, with a normal chest X-ray, CT thorax and NM whole body bone scan. He was treated with IV fluid resuscitation and pamidronate.

Additional investigations came back and exposed that he was thyrotoxic with T₄ >75 and supressed TSH <0.03. He had a positive TSH receptor antibody of 6.2. A NM thyroid scan with uptake technetium showed enlargement and marked increased uptake in both thyroid lobes consistent with Grave’s disease. He was commenced on carbimazole and monitored in an outpatient endocrinology clinic with a normal follow up calcium level of 2.20.

Hypercalcaemia is most commonly caused by primary hyperparathyroidism¹. Malignancy is another common cause and together they account for the majority of cases of hypercalcaemia (1).

Thyrotoxicosis has been found as a sole cause of hypercalcaemia, however, significant symptomatic hypercalcaemia is rare (2). There have been only a few other case reports of similar symptomatic hypercalcaemia with hyperthyroidism (3). However, in this case his thyrotoxicosis also lead to his pancreatitis through having hypercalcaemia. This case highlights that thyroid function tests should always be done when presented with a high calcium level.

References: 1. McCance KL & Huether SE. Pathophysiology: the biologic basis for disease in adults and children. 4th edn, 2002.

2. Daly JG, Greenwood RM & Himsworth RL. Serum calcium concentration in hyperparathyroidism at diagnosis and after treatment. Clin Endocrinol 1983 397–404.

3. Harper PS & Hughes RO. Severe hypercalcaemia from hyperthyroidism with unusual features. BMJ 1970 213–214.