Pseudoarthrosis and fracture: interaction between severe vitamin D deficiency and primary hyperparathyroidism

A young woman with severe vitamin D deficiency presented with proximal muscle weakness, fragility fracture and pseudoarthrosis. On evaluation, she was found to have hypercalcaemia, a single parathyroid adenoma and an undetectable 25-hydroxyvitamin D level. She received parenteral cholecalciferol and subsequently underwent curative parathyroidectomy. Postoperatively, she had hungry bone syndrome, which she gradually recovered from with calcium and calcitriol replacement. Notably, her calcium levels were in the lower limit of normal range and associated with elevated alkaline phosphatase levels at postoperative Day 14. Follow-up for the next four years showed that the patient had remarkable symptomatic and radiological improvements. In this report, we discuss the pathophysiological interactions between vitamin D deficiency and associated primary hyperparathyroidism.