Acute orbital inflammatory syndrome secondary to an ANCA-positive small-vessel vasculitis: a case report and review of the literature.

A 61-year-old man presents with sequential painful bilateral proptosis within 36 h and orbital compartment syndrome resulting in complete loss of vision bilaterally. Sequential urgent lateral canthotomy and cantholysis were performed to reverse the compartment syndrome. Orbital imaging showed non-specific orbital inflammation. Biopsies showed necrotizing inflammation and bloodwork was positive for c-ANCA. The patient was therefore treated with prednisone and cyclophosphomide and showed good recovery of vision in one eye, and had no recurrence of orbital inflammation. ANCA-associated orbital vasculitides are rare, but must be kept in mind in the differential diagnosis of acute orbital inflammatory syndromes.