Orbital inflammation following zoledronic acid infusion

Bisphosphonates, including zoledronic acid, are widely used for the treatment of osteoporosis, Paget's disease, and malignant bone metastases by inhibiting osteoclast-mediated bone resorption. While bisphosphonates are commonly associated with mild side effects such as fever, more severe complications like osteonecrosis of the jaw and hypocalcemia are less common but possible. A rare but clinically significant potential adverse effect that has previously been reported is orbital inflammation (OI), with patients presenting with symptoms of eye pain, orbital swelling, and conjunctival injection.

This case report details the experience of a 76-year-old man who developed OI after his first zoledronic acid infusion for osteoporosis. The patient presented with left eye pain, swelling, and diplopia 2 days post-infusion, along with systemic symptoms of chills and vomiting. MRI confirmed orbital inflammation, and elevated inflammatory markers were noted with no evidence of systemic infection or autoimmune disease. The patient was treated with IV methylprednisolone (1000 mg daily for 3 days), leading to significant symptom improvement within 12 h. A subsequent 7-week prednisone taper was well-tolerated, with full resolution of symptoms at follow-up.

This report underscores both the importance of recognizing rare events such as OI after ZA infusion and uncertainty about the best treatment regimen. While corticosteroids are the mainstay of treatment for OI, corticosteroids are deleterious for bone health and there is no consensus on optimal dosing or tapering duration. Given the clinical importance of bisphosphonates, clinicians should be aware of this potential adverse effect and consider standardized management protocols.