An Unusual Case of Factitious Disorder Manifesting as Hypercalcemia Mediated by Exogenous Calcitriol

Excessive 1, 25-dihydroxy vitamin D (calcitriol) is a pathophysiological cause of hypercalcemia. This form of hypercalcemia is seen in autoimmune conditions, fungal infections, lymphoma, and rare genetic diseases. A factious disorder manifesting as intentional ingestion of calcitriol leading to hypercalcemia has not been previously reported. We report a case of a female in the fourth decade with recurrent episodes of hypercalcemia seen at multiple clinics across the United States over a period of 20 years. Several extensive medical workups were unable to identify a specific cause of her non-PTH mediated hypercalcemia. We used a novel approach to determine that her hypercalcemia was secondary to exogenous calcitriol administration. When the patient realized that the etiology had been identified, she refused all further contact with the physician. It is not uncommon for patients with a factitious disorder to deny self-inflicting behavior or to seek care somewhere else. Ingestion of calcitriol should be considered when the etiology of recurrent hypercalcemia cannot be identified by traditional medical testing.