Challenges in the differential diagnosis of hypercalcemia: A case of hypercalcemia with normal PTH level

Area of Science:

• Endocrinology
• Oncology
• Internal Medicine

Background:

• Hypercalcemia is a common endocrine disorder with diverse causes, ranging from mild to life-threatening.
• Accurate diagnosis typically relies on serum calcium and parathyroid hormone (PTH) levels.
• Coexisting conditions causing hypercalcemia are rare but can complicate diagnosis and management.

Purpose of the Study:

• To report a rare case of concurrent primary hyperparathyroidism and malignancy-associated hypercalcemia.
• To emphasize the diagnostic challenges posed by dual etiologies of hypercalcemia.
• To highlight the importance of considering rare co-occurrences in clinical practice.

Main Methods:

• Case report of an 83-year-old male with severe symptomatic hypercalcemia.
• Utilized serum calcium and parathyroid hormone (PTH) level monitoring.
• Observed patient response to intravenous bisphosphonate therapy.

Main Results:

• The patient presented with severe hypercalcemia and high-normal PTH levels.
• Dual causes (primary hyperparathyroidism and malignancy-associated hypercalcemia) were identified during hospitalization.
• A rapid increase in PTH after bisphosphonate treatment, alongside decreasing serum calcium, revealed the coexistence of both conditions.

Conclusions:

• Concurrent primary hyperparathyroidism and malignancy-associated hypercalcemia is a rare clinical event.
• This dual etiology can present with normal or high-normal PTH levels, complicating diagnosis.
• Recognition of such rare co-occurrences is crucial for appropriate diagnostic workup and therapeutic interventions.