Multiple Spontaneous Vertebral Fractures in a Younger Post-menopausal Woman Upon Stopping Denosumab Therapy

Denosumab is a widely used medication for the treatment of osteoporosis. It has been observed in recent years that abruptly stopping denosumab leads to an increase in bone turnover markers, a decrease in bone mineral density, and a higher incidence of vertebral fractures. We present the case of a 53-year-old woman with few comorbidities and no prior fragility fractures who experienced 4 spontaneous and severely debilitating vertebral fractures 5-months post denosumab discontinuation. At the time of her fractures, she was found to have markedly elevated bone turnover markers, despite bone mineral density that was not significantly changed from measurements done while on denosumab treatment. She went on to be treated with an alternative antiresorptive agent, risedronate, and had substantial declines in her bone turnover markers, along with clinical improvement in her back pain. She experienced no further fractures while on treatment. Abrupt discontinuation of denosumab without starting an alternative antiresorptive agent can lead to spontaneous vertebral fractures. These fractures can occur in young patients with no prior history of fragility fractures and can be severely debilitating. An alternative antiresorptive agent should be started in the case of denosumab discontinuation.