8643 Acute Anterior Uveitis Complicating Zoledronic Acid Infusion

Disclosure: H.F. Belal: None. G.Y. Gandhi: None. Background: Zolendronic acid is a nitrogen-containing, third-generation intravenous bisphosphonate commonly used to treat osteoporosis, Paget’s disease, and solid tumor bone metastasis due to its antiresorptive properties. Well-recognized side effects of bisphosphoantes include acute phase flu-like symptoms, hypocalcemia, renal toxicity, and jaw osteonecrosis. Acute anterior uveitis is a rare but serious side effect of bisphosphonates that has been reported in 0.8-1.1% of patients. Clinical Case: A 75-year-old female with a history of malignant melanoma (s/p wide resection) and current tobacco use presented for evaluation of osteoporosis. She had premature menopause that had not been treated with estrogen. She had pronounced kyphosis and an antalgic gait. Laboratory workup revealed normal serum calcium, thyroid function, renal function, and vitamin D level. CT imaging revealed T5, T7, T11, and T12 vertebral compression fractures with up to 50% loss of height. DEXA scan was notable for a femur neck T score of -3.2. She was started on oral alendronate 70 mg once weekly. However, she discontinued it after one dose due to fatigue. She then received one dose of intravenous zolendronate 5 mg. Three days later, she developed fatigue, nausea, decreased appetite, severe bilateral eye pain, blurry vision and photophobia. She was urgently evaluated by ophthalmology and found to have severe bilateral acute anterior uveitis. She was treated with high-dose oral prednisone with the resolution of uveitis. Conclusion: The mechanism of bisphosphonate-associated ocular reactions is thought to be activation of T cells producing inflammatory cytokines and macrophages. Manifestations include ocular pain, blurred vision, photosensitivity with flares, hyperemia, ciliary spasms, and synechiae. The most common eye-related side effect is conjunctivitis. However, uveitis and scleritis are the most severe eye reactions which require discontinuation of bisphosphonate use. Onset is usually 2 to 4 days after infusion but can occur up to 7 days later. Uveitis and scleritis have fulfilled the WHO Causality Guide of Suspected Adverse Reactions criteria and are deemed certain side effects of bisphosphonates. Recommended treatments include ocular corticosteroids and cycloplegics. Systemic corticosteroids have been used in severe cases. Symptoms typically improve over four weeks of treatment with corticosteroids without long-term sequelae. Rates of complications are also higher when bisphosphonates are used for malignancy compared to osteoporosis. Intravenous forms, such as pamidronate and zoledronate, tend to have higher rates and faster onset of ocular inflammation. Clinicians should be aware of and counsel patients with risk factors for uveitis (i.e., rheumatological inflammatory disorders, smoking) of this rare side effect and instruct them to seek immediate ophthalmological care. Presentation: 6/3/2024