ODP079 BCG-Osis, a Rare Cause of 1,25 Hydroxy Vitamin D Mediated Hypercalcemia

Abstract Background Non-parathyroid hormone (PTH) mediated hypercalcemia is mostly related to malignancy and less commonly caused by granulomatous diseases. We report a rare case of severe hypercalcemia caused by systemic granulomatous disease after intravesical Bacillus Calmette-Guerin (BCG) treatment for bladder cancer (BCGosis). Clinical Case 74-year-old male with history of bladder cancer treated with intravesical BCG a year ago, was hospitalized with confusion, weakness, recurrent falls and polyuria for a few days. He had night sweats and 50 lb weight loss over 6 months. Lab evaluation showed hypercalcemia with calcium 10.9 mg/dL, albumin 3.6 g/dL, corrected calcium 11.2 mg/dL, PTH 12 pg/ml, and 25 OH vitamin D 44ng/ml. He had normal thyroid hormone levels, serum electrophoresis and PTHrP Conclusion Intravesical BCG treatment can be associated with systemic reactions in 1- 5% of patients. Granulomas associated with disseminated BCG infection can lead to hypercalcemia due to increased 1-alpha-hydroxylase activity in macrophages, causing elevated 1,25 OH vitamin D levels. Therefore, evaluation of 1,25 OH vitamin D levels is critical to determine the etiology of hypercalcemia. Treatment of underlying BCGosis with anti-tuberculosis treatment is key in management of hypercalcemia along with supportive treatments that may include IV hydration, bisphosphonates and/or glucocorticoids. Presentation: No date and time listed