Endocrine Abstracts

Background: Calcitriol-induced hypercalcemia is uncommon posing diagnostic dilemma. This case report describes a patient with severe hypercalcemia due to granulomatous changes around a polyethylene wear hip prosthesis.

Case Report: An 80-year-old woman presented with hypercalcemia and stage 3 acute kidney injury. Serum calcium was 3.9 mmol/l, Parathyroid hormone 0.2 pmol/l(1.3 - 9.3), confirming PTH-independent hypercalcemia. CT and MRI imaging, tumor markers and bone marrow biopsy did not reveal a neoplastic process. FDG PET-CT indicated increased uptake around the left hip prosthesis, suggesting inflammation and mild to moderate FDG avidity in left external iliac and common iliac lymph nodes. No bone lesions identified. Lymph node biopsy was attempted but failed. There was no convincing evidence for lymphoma. MRI of the hip showed features of a pseudotumor around metal debris. Metal on Nonmetal prosthesis was evident. She had significantly Elevated 1,25-dihydroxyvitamin D at 282 pmol/l (55-139). Blood tests were negative for Angiotensin converting enzyme and PTH related peptide. Histological diagnosis was avoided due to surgical risk. The diagnosis of calcitriol mediated hypercalcemia secondary to granulomatous inflammation around polyethelene wear was considered in the context of previous hip surgery and the absence of other obvious causes. She was initially managed with hydration and Denosumab; followed by oral prednisolone 20 mg daily which was tapered off over a course of year with satisfactory response.

Conclusion: Calcitriol-induced hypercalcemia due to granuloma, though rare, can be severe and associated with renal injury. Vitamin D metabolite levels are crucial for diagnosis, and steroid therapy is promisingly effective.