Hypercalcaemia due to isolated elevation of 1,25-dihydroxyvitamin D in patients with Crohn's disease.

Crohn's disease is frequently associated with hypocalcaemia following poor calcium intake and decreased intestinal calcium absorption due to malabsorption-related vitamin D deficiency. Severe hypercalcaemia found in Crohn's disease is an unusual clinical entity. We chronicle here the case of a patient who developed hypercalcaemia with elevated 1,25-dihydroxyvitamin D during Crohn's disease exacerbation. Furthermore, we conducted a systematic literature search of MEDLINE, Cochrane, Embase, and Scopus databases regarding 1,25-dihydroxyvitamin D-associated hypercalcaemia in Crohn's disease. A comprehensive review of the search results yielded a total of five case reports only. The data on patient demographics, clinical features, serum calcium levels, Crohn's disease activity site, treatment strategy, hypercalcaemia resolution time and outcomes were collected and analysed. This paper illustrates that Crohn's disease should be added to the list of granulomatous disorders responsible for 1,25-dihydroxyvitamin D-mediated hypercalcaemia. Physicians should maintain a high index of clinical suspicion for this potential complication for prompt management.