A case of acquired fanconi's syndrome and hypophosphatemic osteomalacia induced by prolonged adefovir therapy for chronic hepatitis B

Abstract

A 54-year-old male with chronic hepatitis B infection was referred to our hospital in October 2012 to exam the cause of chest wall pain, hip joint pain and renal impairment Adefovir dipivoxil (ADV) 10 mg a day had been added to lamivudine (LAM) 100 mg a day in 2004 due to lamivudine resistance. Laboratory data on his first visit to our hospital showed elevated serum creatinine, elevated serum alkaline phosphatase, low serum uric acid and phosphate level. Urinalysis showed proteinuria and glucosuria. Urinary uric acid and Β2 microglobulin were elevated. A whole body bone scintigraphy revealed an abnormal distribution of 99mTc uptake, with characteristic changes compatible with osteomalacia. From these results, we diagnosed acquired Fanconi's syndrome and osteomalacia in this patient. Concomitant with this diagnosis, we suspected that ADV was the cause of the Fanconi's syndrome, and ADV and LAM were changed to entecavir 1 mg a day. After stop of ADV and treatment with calcitriol, his bone pain improved within a few months His laboratory data have also improved gradually and abnormal 99mTc uptake has disappeared. Several hypophosphatemic osteomalacia cases induced by ADV have been reported. In previously reported cases, however, a process of recovery in detail was not described. So we report a detail clinical course of patient with osteomalacia associated with Fanconi's syndrome due to ADV therapy. © 2014 The Japan Society of Hepatology.