INSUFFICIENCY FRACTURES DUE TO HYPOPHOSTEMIC OSTEOMALACIA CAUSED BY ADEFOVIR INDUCED FANCONI'S SYNDROME

In patients with chronic hepatitis B infection with high viral loads, Adefovir dipivoxil (ADV) is a commonly used antiviral drug (1). Though studies have shown 10 mg day dosage of ADV to be safe, very rarely, long term treatment can result in Fanconis syndrome, a generalized dysfunction of the renal proximal tubular cells (2). In Fanconis syndrome there is impaired reabsorption of important metabolites with increased urinary loss of phosphate leading to generalized osteopenia and osteomalacia causing multiple insufficiency fractures (1). Here we report a case of multiple insufficiency fractures caused by hypophosphatemic osteomalacia due to Fanconis syndrome as a result of long term usage of ADV at the dose of 10mgday. In the setting of chronic hepatitis B infection causing chronic liver disease, bony metastases from hepatocellular carcinoma could be a close differential to multiple insufficiency fractures and needs to be carefully ruled out. Through this case we would like to indicate that even a conventional dose of 10mgday of ADV in patients with chronic hepatitis B infection can cause hypophosphatemic osteomalacia associated with Fanconi's syndrome. We recommend that patients treated with long-term ADV should be carefully monitored for the occurrence of ADV-induced Fanconi's syndrome.