An Overlooked Medication-Induced Celiac Flare Complicating Treatment of Osteoporosis

Background/Objective: Celiac disease, an immune reaction to gluten causing nutrient malabsorption, and long-term glucocorticoid therapy adversely affect bone metabolism and increase fracture risk. Case Report: A patient with long-standing celiac disease on a strict gluten-free diet and long-term glucocorticoid therapy status post kidney transplant for Sjo<euro>gren syndrome-induced interstitial nephritis presented for management of osteoporosis. Initial evaluation was notable for secondary hyperparathyroidism, which resolved after switching to a gluten-free calcium citrate supplement. Given normal serum total alkaline phosphatase (ALP) and parathyroid hormone (PTH), she began treatment of osteoporosis with abaloparatide. Two months later, she reported abrupt onset of diarrhea with significant weight loss. Biochemical investigation revealed a threefold increase in serum ALP level. As a precaution, abaloparatide was suspended, yet symptoms persisted with elevated ALP and PTH levels. Endoscopy revealed a celiac flare. The clinic-based pharmacist found that her pharmacy had inadvertently dispensed prednisone tablets containing wheat starch. A switch to a gluten-free formulation led to rapid resolution of the diarrhea with weight regain. Serum ALP and PTH levels normalized, and abaloparatide was resumed without biochemical abnormalities. Discussion: An unintended switch to a gluten-containing prednisone formulation resulted in uncontrolled celiac disease causing calcium malabsorption, secondary hyperparathyroidism, elevated ALP levels, and an interruption in osteoporosis therapy. Common supplements and drugs can be a hidden source of gluten. Collaboration with a clinic-based pharmacist enhances the detection and prevention of medication-induced adverse reactions. Conclusion: This case highlights the importance of a careful review of gluten-containing medications and supplements in patients with celiac disease. (c) 2024 AACE. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).