Denosumab improves clinical manifestations of hypophosphatem
A 60-year-old Japanese man had been receiving low-dose adefovir dipivoxil (10 mg/day) to treat chronic hepatitis B for approximately 5 years. He presented to an orthopedic surgeon with severe pain of the right hip and no trauma history, and fracture of the neck of the right femur was identified. In addition, 99mTc-hydroxymethylene diphosphate scintigraphy revealed significantly abnormal uptake in the bilateral ribs, hips, and knees, and he was therefore referred to our university hospital for evaluation of multiple pathological fractures.

Hypophosphatemic osteomalacia was diagnosed due to Fanconi syndrome induced by adefovir dipivoxil therapy. Although the patient’s adefovir dipivoxil dose was reduced and calcitriol (active vitamin D3) was added, he did not respond and continued to complain of bone pain. Several bone resorption markers and bone-specific alkaline phosphatase were also persistently elevated. Therefore, denosumab was added to vitamin D3 supplementation for treatment of excessive bone resorption. Two months after initiation of denosumab, his hip and knee pain was relieved, along with a decrease in serum alkaline phosphatase and some bone resorption markers.

Source: Journal of Medical Case Reports 2019 13:99

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