Two Case Reports of Zoledronic Acid-Induced Acute Anterior Uveitis

Zoledronic acid, or zoledronate, is a nitrogen-containing bisphosphonate widely used to treat osteoporosis and metastatic bone disease. It inhibits osteoclast function by binding to hydroxyapatite, reducing bone resorption and increasing bone mineral density. Despite its proven efficacy in increasing bone mineral density and reducing the incidence of fractures, adverse effects have been documented, including ocular side effects such as acute anterior uveitis. It's well known that osteoporosis primarily affects postmenopausal women and represents a significant economic burden in health care systems due to continued fragility fractures. In this case series, we present two cases of postmenopausal women who have been diagnosed with severe osteoporosis. The first case is a 71-year-old woman with a history of rheumatoid arthritis, and the second is a 67-year-old patient with a history of congenital hip dysplasia. Both patients received IV zoledronic acid for osteoporosis treatment. Within a few days after infusion, both developed symptoms consistent with Zoledronic acid-induced uveitis (ZAIU), including ocular pain, redness, photophobia, and blurred vision. Evaluations included bone densitometry, which confirmed severe osteoporosis, and phosphocalcic metabolism profiles-ocular symptoms, which led to ophthalmology consultations, where ZAIU was diagnosed through biomicroscopy and physical examination. Treatment included ophthalmic corticosteroids, with a posterior patient experiencing symptom resolution without sequelae. However, the occurrence of ZAIU led to a reconsideration of bisphosphonate therapy. Although the incidence of ZAIU following zoledronic acid administration is low, it raises important considerations about managing osteoporosis in susceptible patients. The literature suggests vigilance for ocular side effects and a careful balance between the benefits and risks of bisphosphonate therapy.