Cause or effect? Undetectable vitamin D in a patient with Crohn's disease.

Crohn's disease has been described as the "great mimicker" with a wide array of presentations. We describe a case of a teenager who presented with tetany and undetectable vitamin D as initial presentation of Crohn's disease. There are reports of adults in tetany due to electrolyte derangements in chronic gastrointestinal diseases secondary to malabsorption. However, the role of deficient vitamin D as it contributes to immune system dysfunction has only begun to be explored. Vitamin D is essential for calcium absorption, immune regulation, and gut epithelial barrier. This case report discusses vitamin D physiology and its potential mediation in the pathogenesis of inflammatory bowel disease.