A Case of Primary Hyperparathyroidism With a Hypercalcemic Crisis Resulting in Distinct Bone Mineral Redistribution.

Primary hyperparathyroidism (PHPT) is generally detected early, but this case involves a rare hypercalcemic crisis associated with a parathyroid adenoma. A 66-year-old man presented with extreme fatigue and loss of appetite. Serum calcium and parathyroid hormone (PTH) levels were elevated to 22.5 mg/dL and 3100 pg/mL, respectively. After the initial management of hypercalcemia, parathyroidectomy confirmed a benign adenoma. This case demonstrates a notable redistribution of bone minerals, with a significant decrease in cortical bone density but preservation, and even enhancement, of trabecular bone density. This redistribution highlights the complex dual action of PTH on bone metabolism, emphasizing the need for careful monitoring in severe PHPT cases.