SAT221 A Case Of Severe Hypocalcemia After Treatment Of Plasma Cell Leukemia

Disclosure: H. Tabassum: None. T. Goettemoeller: None. E.J. Epstein: None. D. Cooper: None. Background: Hypocalcemia has been well described in cancer patients receiving skeletal protecting medications (denosumab and to a lesser extent zoledronic acid) and in patients with osteoblastic metastasis (prostate or breast cancer). A rare cause of hypocalcemia in malignancy has been described following treatment of a multiple myeloma (MM) patient with a high volume of metastatic lytic lesions, with a mechanism thought to be secondary to rapid bone remineralization. Here we report a case of severe and protracted hypocalcemia resulting in a seizure occurring after treatment of plasma cell leukemia. Clinical Case: A 58-year-old male with plasma cell leukemia IgG kappa type and innumerable osteolytic lesions underwent chemotherapy treatment with cyclophosphamide-bortezomib-dexamethasone followed by lenalidomide and carfilzomib-daratumumab-dexamethasone. Prior to treatment initiation, calcium, phosphorus, and magnesium levels were within normal range. No denosumab or bisphosphonates were given. The patient became hypocalcemic within three weeks of initiation of chemotherapy, and he was started on calcium supplementation without improvement. The patient presented to the ED after an episode of seizure, and was found to have severe hypocalcemia with calcium 5.6 mg/dL (N: 8.5 - 10.5 mg/dL), ionized calcium 0.78 mmol/L (N: 1.10 - 1.35 mmol/L), albumin 3.5 g/dL (3.5 - 5.0 g/dL), magnesium