Diagnosis of TIO: Is Serum FGF23 Measurement always the Answer?

Indian Journal of Endocrinology and Metabolism ¦ Volume 24 ¦ Issue 2 ¦ March-April 2020 230 Sir, A 48-year-old perimenopausal woman presented with recurrent fractures of both right and left femur, precipitated by minimal trauma while walking, one in May 2017 and another in June 2018. She had consulted local hospital for the same and was under management for primary osteoporosis based on DEXA scan reports showing a T score of less than -2.5. She was started on IV zoledronic acid 1 year ago, with precipitation of acute bone pains. Following this, 3 months later, she was started on Inj. teriparatide 20 μg daily. However, she had been worked up for metabolic bone disease, which was considered negative by her treating team. There was, however, a marginal elevation of PTH levels (80 pg/ ml). Despite being on teriparatide, her bone pains had worsened which restricted her daily activity significantly; she was wheelchair bound for 2 months, at the time of presentation. On examination, while presenting at our center, the patient was nonambulant with severe proximal weakness and bone pains. Even slight involuntary movements associated with bone tenderness.