Hyperparathyroidism in Emergency Medicine Differential Diagnoses

Updated: Oct 13, 2021
  • Author: Philip N Salen, MD; Chief Editor: Erik D Schraga, MD  more...
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Diagnostic Considerations

Hyperparathyroidism is the most common cause of hypercalcemia in the outpatient setting. [21]  

Thiazide diuretics and lithium can alter calcium homeostasis.  Thiazide diuretics cause mild hypercalcemia by reducing urinary calcium excretion. If hypercalcemia persists after stopping the thiazide diuretic, PHPT is likely. Patients on long-term lithium therapy uncommonly develop hypercalcemia secondary to lithium decreasing the parathyroid gland’s sensitivity to calcium, and resulting in increases in serum levels of calcium and PTH. [15]

Differential Diagnoses