Immobilization-Related Hypercalcemia in a COVID-19 Patient With Prolonged Intensive Care Unit Stay.

Immobilization-related hypercalcemia is an uncommon finding in patients admitted to intensive care unit. We report a case of severe hypercalcemia in a COVID-19 patient admitted to intensive care unit for hypoxemic respiratory failure. He developed an acute kidney injury requiring continuous renal replacement therapy with regional citrate anticoagulation. Citrate chelates ionized calcium and stop the coagulation cascade locally, preventing filter clotting. Calcium is then given intravenously to a specific target (normocalcemia). It is only when calcium infusion has been stopped that bone resorption and hypercalcemia were unmasked.