Objective: To present a case that illustrates the importance of considering asymptomatic celiac disease (CD) as a possible underlying cause in some cases of normocalcemic primary hyperparathyroidism.
Methods: We describe the clinical presentation, management, and outcome of a case of severe primary hyperparathyroidism manifesting with normocalcemia, likely attributable to the presence of asymptomatic CD.
Results: A 24-year-old woman presented with a 5-year history of generalized weakness, which had progressed until use of a wheelchair became necessary. She also had sustained low-trauma fragility fractures of the right tibia and left femur. She had no symptoms suggestive of CD. Physical examination revealed severe proximal myopathy. Laboratory data (and reference ranges) were as follows: serum calcium, 2.34 mmol/L (2.1 to 2.6); phosphorus, 0.91 mmol/L (0.90 to 1.50); alkaline phosphatase, 421 U/L (40 to 135); albumin, 37 g/L (35 to 45); parathyroid hormone, 874 ng/L (15 to 65); urine calcium, 3.76 mmol/d (2.5 to 8); and 25-hydroxyvitamin D, <13 nmol/L (22 to 116). She was treated with increasing doses of calcitriol, ergocalciferol, and calcium carbonate, but the serum calcium concentration did not increase substantially (reaching a maximum of 2.70 mmol/L on suprapharmacologic doses of these agents). Malabsorption was considered as an explanation for this apparent resistance to these medications. The result of antibody screening for CD was highly positive, and a distal duodenal biopsy confirmed the diagnosis of CD. A technetium Tc 99m sestamibi scan revealed uptake in the neck that was consistent with a single parathyroid adenoma, which was surgically removed. Treatment with a gluten-free diet, calcium carbonate, and ergocalciferol yielded remarkable clinical, biochemical, and radiologic improvement.
Conclusion: Asymptomatic CD may be the underlying cause for some cases of normocalcemic primary hyperparathyroidism, and it should be considered in this setting.