Successful Corticosteroid-Sparing Effect of Rituximab in the Treatment of Refractory Idiopathic Orbital Inflammatory Disease
A 61-year-old woman presented with symptoms of left-sided headache, peri-orbital pain and left-sided ocular protrusion. Examination revealed a decrease in her visual acuity from 6/6 to 6/24, which was associated with a left-sided relative afferent pupillary defect. Her left eye was proptotic by 3 mm on exophthalmometry, with associated ocular pain and conjunctival injection (fig. ). Extraocular movements were normal and intraocular examination proved unremarkable.\nBlood investigations including thyroid function tests, fasting blood glucose, liver and renal function tests, erythrocyte sedimentation rate and serum ACE were all normal, as was an immune screen including rheumatoid factor, antinuclear antibody and antineutrophil cytoplasm antibody.\nA provisional diagnosis of left IOID was made based on the clinical findings and negative blood investigations, and oral prednisolone was started at a dose of 60 mg/day. Her symptoms resolved rapidly and her vision and proptosis improved within days, supporting the diagnosis. However, she suffered a disease relapse when her prednisolone was tapered to 20 mg/day. Subsequent attempts at steroid sparing with mycophenolate mofetil 1 g b.i.d. and methotrexate 20 mg p.o. weekly proved ineffective over a period of 8 months. The patient started again at 60 mg/day prednisolone together with each second-line agent, but she was unable to get below 20 mg prednisolone without renewed disease activity. Measurement of IgG subclasses at this point demonstrated normal IgG4 levels, although this result may have been confounded by her concurrent treatment with corticosteroids and other immunosuppressive medication.\nShe then received 2 infusions of rituximab 1 g i.v. separated by an interval of 2 weeks. This effected disease remission within 4 weeks and enabled her prednisolone to be tapered to 7.5 mg o.d. without relapse over a period of 2 months. Nine months on, she remains in remission on 7.5 mg prednisolone only and maintains a visual acuity of 6/6 with no relative afferent pupillary defect, and no abnormalities on repeat MR scanning (fig. ).