Endocrine Abstracts

We present the case of a 74-year-old man who was admitted with a short history of confusion and reduced mobility. He had a raised serum corrected calcium (cCa) of >5 mmol/l, serum parathyroid hormone (PTH) of 1.9 pmol/l (range 1.6–6.8 pmol/l) and acute renal failure. He was rehydrated and given a dose of i.v. zoledronate. Two days later his serum cCa remained elevated (4.39 mmol/l) with persistently impaired renal function. He underwent dialysis and serum cCa improved transiently, the nadir value being 2.94 mmol/l.

Imaging with computed tomography showed incidental acute pancreatitis, bilateral pleural thickening, and mild pulmonary fibrosis. Myeloma screen was negative. Repeat PTH levels were elevated between 99 and 205 pmol/l. Sestamibi scan was equivocal but suggestive of a left inferior parathyroid adenoma. Ultrasound showed a 1.7 cm by 1.6 cm by 3.2 cm adenoma at the inferior pole of the left thyroid gland.

It emerged that he presented to his local hospital 7 years previously with similar symptoms and a serum cCa of 5.53 mmol/l. He had received bisphosponate and i.v. fluids but refused further assessment.

A second dose of bisphosphonate (cCa >3 mmol/l) resulted in minimal lowering of serum cCa and he was commenced on cinacalcet and i.v. fluids. A third dose of bisphosphanate again resulted in only a transient improvement in hypercalcaemia.

He was referred for a surgical opinion and underwent inpatient parathyroidectomy. He required further dialysis pre-operatively as his cCa was around 3.7 mmol/l. Postoperatively, serum cCa and PTH normalised. Histology of the 3.5 cm parathyroid lesion showed no evidence of malignancy.

This case highlights the clinical challenges we faced in managing this gentleman’s severe hypercalcaemia. To our knowledge, there has been no case report of such resistant hypercalcaemia secondary to a parathyroid adenoma. Once the diagnosis is established, urgent referral for inpatient parathyroidectomy may reduce the morbidity associated with this condition.