SAT-789 - Unilateral Retro-Orbital Cellulitis Following Bisphosphonate Infusion

Introduction:

Bisphosphonate is commonly used for the treatment of osteoporosis, bone metastasis, and multiple myeloma, osteitis deformans, and osteogenesis imperfecta. The most common adverse effects are acute phase reaction (flu-like symptoms, myalgia), hypocalcemia, osteonecrosis of the jaw, and atypical femoral fracture. A few cases of orbital inflammation have been reported after bisphosphonate infusion.

Case description:

A 66-year-old F with PMH of Sjogren syndrome on hydroxychloroquine and methotrexate, adenocarcinoma of the colon with liver metastasis, in remission, found to have osteoporosis by routine DXA imaging in May 2025. She received her first Zoledronic acid 5 mg infusion on 12/12/2025, experienced flu-like symptoms after that. She reported right retroorbital pain initially, later developed right upper eyelid swelling and redness; pain with eye movement, and diplopia associated with headache. She visited the primary care provider's office on 12/17/2025, referred to the ER for further evaluation. The Ophthalmology exam was significant for: swelling of the right upper and lower eyelid, conjunctival redness, right eye abduction defect, reduced upward and downward movement, and normal intraocular pressure. Her CRP was 1.43 (high); CT face with IV contrast showing evidence of right sided orbital cellulitis - fat stranding in the right retro-orbital, pre-septal periorbital region, and mild exophthalmos. CT venography showed patent dural venous sinuses. Due to her immunosuppressed conditions, she started on intravenous antibiotics of ceftriaxone and vancomycin. Following ophthalmology evaluation, the patient was started on prednisone 60 mg daily due to concern of bisphosphonate induced orbital inflammation. Her right sided orbital swelling, and vision improved the next day; vancomycin was discontinued after 24 hours. The patient was discharged with methyl prednisone with slow tapering. Endocrinology office visits 2 weeks following discharge showed improvement of ocular signs and symptoms.

Conclusion:

Ocular complications following bisphosphonate therapy are rare; seen more after infusion than oral administration. In a cohort study, the most common ocular adverse effect was dry eye 1.73%, cornea and ocular surface inflammations 0.97%, and uveitis found to be 0.17%. Mostly seen in first-time users, with coexisting inflammatory conditions associated with ocular involvements, typically occur within 24-72 hours but can range from a few hours to 3 years. In our patient, symptoms started after systemic bisphosphonate infusion and improved after prednisone. Her history of Sjogren syndrome is another potential risk factor for her ocular adverse effect. Recurrence of symptoms found on rechallenge with pamidronate disodium. Close ophthalmology follow-up, along with alternative therapy for osteoporosis, is recommended.

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