Zoledronic acid-induced orbital inflammation
C. Start corticosteroids
This patient with multiple myeloma presented with acute unilateral orbital congestion and ophthalmoplegia and was initially treated for presumed orbital cellulitis. His condition worsened despite treatment with broad-spectrum intravenous antibiotics, thus raising suspicion for an alternative etiology. Although invasive fungal sinusitis was considered on the differential diagnosis due to his immunocompromised state, neither bedside nasal endoscopy nor computed tomography of the sinus was suggestive of the disease. Therefore, antifungals were not started (choice A), and sinus biopsies were not pursued (choice B).
An inflammatory etiology was considered, given the multifocal involvement observed on imaging (right orbit, left sphenoid sinus, masticator space). On further probing, the patient reported he received his first infusion of zoledronic acid, a bisphosphonate, as part of his treatment for multiple myeloma 3 days prior to presentation. Given the acute onset of symptoms within 72 hours of the first zoledronic acid infusion, a diagnosis of orbital inflammatory disease due to bisphosphonate infusion was suspected. Treatment with intravenous pulse methylprednisolone was initiated (choice C). Due to the suspected etiology and the acute nature of the presentation, an orbital biopsy would not be the best next option (choice D).