Zoledronic acid-induced orbital inflammation: a diagnostic challenge

Introduction: Zoledronic acid is a bisphosphonate widely used for osteoporosis and other bone disorders. In rare cases, it can cause ocular inflammation mimicking orbital cellulitis. Case description: A 52-year-old woman developed right eye pain and swelling within 24 hours of her first zoledronic acid infusion. Examination revealed conjunctival redness and mild eyelid swelling without proptosis, ophthalmoplegia, or vision loss. Laboratory markers were largely normal. Computed tomography scan and magnetic resonance imaging showed preseptal and postseptal inflammation without abscess formation. Treatment with corticosteroids and antibiotics resulted in complete symptom resolution within one week. Conclusion: Zoledronic acid can induce rapid-onset orbital inflammation. Awareness of this rare adverse effect is essential to avoid misdiagnosis and ensure timely treatment. LEARNING POINTS: Bisphosphonate ocular toxicity may mimic common eye conditions but often resists standard treatment; clinicians should consider drug-induced causes in refractory cases.Temporal association with bisphosphonate therapy is crucial for diagnosis; rapid onset after infusion can indicate drug-induced orbital inflammation.Early corticosteroid therapy typically leads to full recovery, highlighting the importance of prompt recognition and management.