From Hypocalcemia to Hypercalcemia—An Unusual Clinical Presentation of a Patient With Permanent Postsurgical Hypoparathyroidism

Context: Hypercalcemia associated with lymphomas can be secondary to increased calcitriol [1,25(OH)2 vitamin D3], PTHrP, or osteolytic metastases. Objective: A case of calcitriol-mediated hypercalcemia secondary to non-Hodgkin lymphoma in a patient with postsurgical hypoparathyroidism is presented. Design and Setting: Single patient managed at a tertiary health care facility in the United States. Patient: A 55-year-old white woman had a total thyroidectomy and radioiodine ablation for a 3.5-cm follicular carcinoma. Surgery was complicated by permanent hypoparathyroidism treated with calcium, calcitriol, and cholecalciferol. For over 16 years she had no evidence of either residual thyroid tissue in the neck or metastasis. Her corrected serum calcium levels were appropriately maintained in the low-normal range. During a routine clinic visit, she had mild hypercalcemia; calcium and cholecalciferol were reduced by 50%, while calcitriol was continued. Two weeks later, she presented with nausea, abdominal pain,...