Adefovir Dipivoxil-induced Osteomalacia: A Rare Case of Misdiagnosis due to Concurrent Thyroid Tumor

Abstract

Background: Both the administration of adefovir dipivoxil and the elevation of primary parathyroid hormone can result in serum
electrolyte abnormalities and the development of metabolic bone disease. Adefovir dipivoxil-induced osteomalacia is a clinical disease that is
rarely seen and often leads to misdiagnosis. Case presentation: In this case, the patient developed osteomalacia due to renal tubular toxicity
caused by chronic use of adefovir dipivoxil. The drug indirectly affected the secretion of parathyroid hormone (PTH). Coincidentally, the patient also had a tumor below the thyroid, leading to a misdiagnosis. Conclusion: Osteomalacia caused by adefovir dipivoxil is a clinically rare
disease, and it is important not to overlook it as it may lead to misdiagnosis. Hence, in cases where laboratory tests reveal abnormal parathyroid hormone levels, it is crucial to inquire about the patients detailed medication history. This is applicable even in situations where there is
evidence suggesting primary hyperparathyroidism.