# Hypercalcemia: Let PTH Organize the Differential

Definitive care follows the cause. Recheck medications, calcium intake, kidney effects, and treatment-related electrolyte changes.

![Infographic: Hypercalcemia: Let PTH Organize the Differential](https://urinenephrology.org/visual-reference/images/mastery-hypercalcemia.png?v=20261003c)

## Excess calcium has many sources

Increased bone release, enhanced absorption, impaired excretion, and medication effects can raise serum calcium. The mechanism determines the treatment path.

## Recognize significant illness

Confusion, weakness, vomiting, dehydration, arrhythmias, and kidney dysfunction can signal a clinically important disturbance.

## Let PTH choose the branch

Confirm hypercalcemia, then measure PTH. An elevated or inappropriately normal PTH points toward primary/tertiary hyperparathyroidism or a calcium-sensing disorder. Suppressed PTH prompts a directed search for malignancy, vitamin D-mediated disease, medications, and supplements; parathyroid localization imaging does not make the biochemical diagnosis.

## Investigate the branch

Consider parathyroid disease, malignancy, vitamin D-mediated processes, granulomatous disease, medication exposure, and inherited calcium-sensing conditions.

## Match urgent therapy to mechanism

For hypercalcemia of malignancy, antiresorptive therapy addresses bone-mediated calcium release; short-term calcitonin can bridge its delayed onset in severe disease. Restore volume only as tolerated. Calcitonin loses effectiveness with prolonged use; glucocorticoids have a different role in selected calcitriol-mediated causes.

## Prevent recurrence

Definitive care follows the cause. Recheck medications, calcium intake, kidney effects, and treatment-related electrolyte changes.

## Supporting evidence

- [Supporting guideline or source](https://www.endocrine.org/clinical-practice-guidelines/hypercalcemia)

## Source lessons

- [hypercalcemia review](https://urinenephrology.org/mastery/electrolytes-advanced/hypercalcemia-review.html)

Read alongside the full lessons; the findings and decisions shown here require the stated clinical context.