Endocrine Abstracts

Case: A 34-years-old male, construction worker, referred by GP with the history of vomiting, fatigue and near-collapse. Apart from alcohol excess, his past medical history was unremarkable. He did not have any personal or family history of any endocrinopathy, and was not taking any medication. Initial blood result were as below. ECG showed short QTc interval of 354 ms. His presentation was initially thought to be vomiting due to alcohol excess leading to dehydration and hypercalcaemia with AKI. He was commenced on IV fluids and Pabrinex. Further tests showed suppressed PTH 0.5 pmol/l, TSH 1.4mU/l, and negative myeloma screen. CT thorax was normal which excluded sarcoidosis, TB, and malignancy, therefore, a possible explanation of PTH independent severe hypercalcaemia was made. His vitamin D level returned after a few days which was grossly elevated at 1821 nmol/l. On direct questioning, he reported taking 50,000IU vitamin D injection every 1-2 days for last several months, which he bought online without any medical advice or supervision. He was given IV zoledronic acid due to inadequate response from IV fluids alone. He was counselled against the use of vitamin D preparation without medical advice or supervision as this could have been fatal in his case. His calcium level normalised and AKI resolved with the resolution of ECG changes after the treatment. Discussion: Among all causes of hypercalcemia, primary hyperparathyroidism and malignancy are the most common, accounting for >90% of cases. Although hypercalcemia due to exogenous use of vitamin D is unusual, it is important to consider it in the differential diagnosis as part of initial work up. This case highlights that this could result in symptomatic life-threatening hypercalcaemia and patient should be effectively counselled regarding perils of over-the-counter vitamin D use.