Celiac disease manifesting as isolated hypocalcemia

Area of Science:

• Gastroenterology
• Endocrinology
• Nutritional Science

Background:

• Celiac disease is an autoimmune disorder triggered by gluten ingestion, primarily affecting the small intestine.
• It often presents with gastrointestinal symptoms but can manifest with extraintestinal complications, including metabolic bone disease.
• Calcium malabsorption is a known complication, typically associated with vitamin D deficiency.

Observation:

• A 36-year-old woman presented with hypocalcemia and hypocalciuria, despite normal serum 25-hydroxyvitamin D and elevated 1,25-dihydroxyvitamin D.
• She exhibited secondary hyperparathyroidism refractory to standard calcium and vitamin D supplementation.
• Intestinal biopsy confirmed celiac disease, and bone density was in the osteopenic range.

Findings:

• The patient's hypocalcemia was attributed to isolated calcium malabsorption, a consequence of proximal small intestine involvement in celiac disease.
• Treatment with a strict gluten-free diet normalized serum calcium and parathyroid hormone levels.
• Bone mineral density significantly improved following dietary intervention.

Implications:

• This case highlights that primary intestinal calcium malabsorption, independent of vitamin D deficiency, can be an early manifestation of celiac disease.
• It underscores the importance of considering celiac disease in patients with unexplained hypocalcemia and hypocalciuria, even with adequate vitamin D status.
• Early diagnosis and gluten-free dietary management are crucial for resolving metabolic bone complications associated with celiac disease.