Severe Hypercalcemia in Primary Hyperparathyroidism Managed with Hemodialysis and Parathyroidectomy

Introduction: We report a case of a 75-year-old female with primary hyperparathyroidism, atrial fibrillation, and dementia, presenting with altered mental status and life-threatening hypercalcemia (corrected calcium 21.4 mg/dL). Imaging showed a large cystic lesion near the thyroid and a suspicious nodule. Due to minimal response to medical therapy, the patient underwent urgent hemodialysis and parathyroidectomy. This case highlights the role of dialysis in managing acute hypercalcemia when surgery is delayed. Case Description: A 75-year-old female with primary hyperparathyroidism, dementia, type 2 diabetes, hypertension, and atrial fibrillation presented with altered mental status and severe hypercalcemia (corrected calcium 21.4 mg/dL). On arrival, she was in acute respiratory failure and intubated. Labs showed markedly elevated PTH (2,383 pg/mL) and ionized calcium (2.36 mmol/L). After minimal response to IV hydration and calcitonin, she underwent hemodialysis with a low-calcium dialysate. Imaging revealed a large adenoma in the right inferior parathyroid gland, which was resected on Day 4. Post-op, her calcium normalized and neurologic status improved. Discussion: This case highlights key considerations in the management of severe hypercalcemia due to primary hyperparathyroidism. The magnitude of hypercalcemia, with a corrected calcium level >21 mg/dL and PTH >2,000 pg/mL, initially raised concern for parathyroid carcinoma. However, parathyroid adenomas can also present with severe hypercalcemia and large gland size, as seen in this case. The right inferior parathyroid gland weighed over 21 g, much larger than typical adenomas and similar to carcinoma, showing that adenomas can present dramatically. Initial therapy with IV fluids and calcitonin had minimal effect, consistent with reports of limited efficacy when calcium exceeds 18 mg/dL. In such cases, particularly with renal dysfunction or neurologic impairment, hemodialysis is an effective temporizing measure. Hemodialysis removes serum calcium through a low-calcium dialysate, enabling rapid correction. Though parathyroid carcinoma was suspected, final pathology revealed a hypercellular adenoma, underscoring the diagnostic challenge. Surgical resection was curative, with significant improvement in calcium levels and mental status postoperatively.