U010

A reminder of the need for a diagnostic approach to hypercalcaemia.

R Jordon, S K Thukral, J F Todd

Imperial Centre for Endocrinology, Hammersmith Hospital

Abstract:

Primary hyperparathyroidism should be considered in all patients presenting with hypercalcaemia. Without appropriate and timely investigation with paired calcium and parathyroid hormone (PTH) levels, the diagnosis can be overlooked. Furthermore, bisphosphonates can complicate these investigations as this case reflects.

A 51 year old lady presented to her local gastroenterology department with a two month history of watery diarrhoea (bowels opening more than twenty times daily), weight loss and facial flushing. She was previously fit and well. On examination she was found to be cachectic with peripheral signs of chronic liver disease and painless hepatomegaly. Stool cultures were negative. Liver function tests were deranged with a largely cholestatic picture. A liver ultrasound showed extensive liver metastases. A subsequent liver biopsy revealed neuroendocrine tumour. Further imaging with gallium DOTATATE PET-CT showed liver metastases and a likely primary at the neck of the pancreas, confirmed with endoscopic ultrasound. Fasting gut hormones showed high vasoactive intestinal peptide (VIP) levels that may be consistent with a VIPoma.

During the admission at her local hospital, she developed hypercalcaemia with a calcium level of 3.54 mmol/L. The referring team treated this with intravenous fluids and two pamidronate infusions. The PTH level taken after the initial pamidronate infusion when the calcium level was 3.28 mmol/L and was inappropriately normal at 2.1 pmol/L. A parathyroid ultrasound showed a possible parathyroid adenoma to be correlated with sestamibi nuclear imaging. She has been now been referred for multiple endocrine neoplasia (MEN) genetic screening.

Consideration of MEN was delayed due to failure to diagnose the underlying cause of hypercalcaemia. This, in part, related to the enthusiastic use of pamidronate prior to investigation. This caused subsequent difficulty in interpreting paired calcium and PTH levels. This case highlights the difficulty in making a diagnosis of primary hyperparathyroidism when hypercalcaemia is treated without a diagnostic approach.