A Rare Presentation of Zoledronate-Induced Systemic Inflammatory Response.

Zoledronic acid is a bisphosphonate commonly used to treat various conditions involving bone loss. While it is generally well-tolerated, the occurrence of severe inflammatory reactions is rare. We present the case of an 82-year-old female who developed a severe immune reaction, including weakness and tenderness in her upper and lower extremities, following a single dose of zoledronic acid infusion for the treatment of osteoporosis. The onset of symptoms occurred one week after the infusion and persisted, progressively worsening over time, leading to functional impairment and the need for a walker for ambulation. Laboratory studies revealed an elevated erythrocyte sedimentation rate while other autoimmune markers were within normal limits. Differential diagnosis included an adverse reaction to zoledronic acid or underlying polymyalgia rheumatica. The patient showed significant improvement with a prednisone taper, suggesting an immune-mediated response. This case highlights the importance of considering severe immune reactions as a potential side effect of zoledronic acid and emphasizes the need for further research to better understand the underlying mechanisms and optimize patient management.