Unilateral optic neuritis, scleritis and exudative retinal detachment due to recurrent orbital pseudotumor

Abstract

Idiopathic orbital inflammation, also known as orbital pseudotumor, describes a spectrum of idiopathic, non-neoplastic, non-infectious, space-occupying orbital lesions without identifiable local or systemic cause. The condition occurs mainly in young adults who may present with acute pain, proptosis, chemosis and limitations of extraocular movements. Decreased vision due to optic nerve infiltration and macular edema as a result of scleritis is less common sequel of orbital pseudotumor. Herein, we present a case of unilateral orbital pseudotumor in a young male who presented with chief complaints of painful decreased vision which was attributed to optic neuritis and macular edema as a result of scleritis. Imaging studies were helpful in the establishment of the correct diagnosis and patient’s complaints improved with administration of systemic corticosteroids.

Introduction

After Graves’ disease and lymphoproliferative disorders, orbital pseudotumor, is the 3rd most common ophthalmologic disease of the orbit which accounts for approximately 8–11% of all the orbital processes. For example, among the 1264 patients referred to Wills Eye Hospital for a suspected orbital mass, inflammatory lesion accounted for 11% of the histopathologically proven cases.¹The current concept of orbital pseudotumor defines it as an idiopathic inflammatory process made up of pleomorphic inflammatory cellular response and a fibrovascular tissue reaction. Histopathological analysis shows a spectrum of granulomatous inflammation, admixed with non-granulomatous inflammation and fibrosis.^2,3 The ocular manifestations of orbital pseudotumor may include periorbital edema, erythema, proptosis, ptosis, diplopia and pain with eye movements.^3–5 Decreased vision due to optic nerve infiltration, and macular edema as a result of scleritis is less common sequel of orbital pseudotumor.^6,7 Herein, we present a case of unilateral orbital pseudotumor in a young male who presented with chief complaints of painful decreased vision which was attributed to optic neuritis and macular edema as a result of scleritis. Imaging studies were helpful in the establishment of correct diagnosis and patient’s complaints improved with administration of systemic corticosteroids.

Case report

A 20-year-old male presented with a two week history of decreased vision and severe right-sided orbital pain with eye movements. His past history was significant for having minimal proptosis on the same side for which he had been diagnosed to have an orbital pseudotumor 4 months earlier but no treatment was offered. On examination his VA was 20/25 in OD and 20/20 in OS, his intraocular pressure was 17 mmHg in OD and 16.5 mmHg in OS. There was no relative afferent pupillary defect. There was 4–5 mm of right-sided proptosis (Fig. 1A and B). On slit-lamp examination, there was evidence of dilated scleral vessels on the right side, anterior chamber was deep, there was no inflammation and his lens was clear. Fundus examination revealed evidence of exudative retinal detachment at the macular area on the right side. Slit-lamp and fundus examinations on the left side were normal. Right-sided ultrasonography (U/S, B-scan) revealed evidence of posterior scleritis along with retinal detachment and T-sign. Spectral Domain Optical Coherence Tomography (OCT) of the macula of the OD revealed evidence of macular detachment (Fig. 1C and D). Computed tomography (CT) scan of the brain and orbits was compatible with right orbital pseudotumor as is evident by the enlarged recti muscles and proptosis. The optic nerve appeared to be diffusely thickened along its orbital course (Fig. 2A–D). The patient was started on systemic corticosteroids that resulted in dramatic improvement of his symptoms. On the third day his vision had improved to 20/20 along with exudative retinal detachment as well as right-sided proptosis.

Figure 1.

External photograph of a 20-year-old male with right eye proptosis and dilated scleral vessels (A and B). U/S (B-scan) revealed evidence of diffuse sclera thickening along with macular detachment (C) which was confirmed by spectral domain OCT of the macula of the right eye (D).

Figure 2.

Computed tomography scans (axial, A; sagittal, B and coronal views, C and D) of the same patient demonstrating evidence of right eye thickened extraocular muscles as well as optic nerve along its orbital track.

Discussion

The case described indicates that patients with orbital pseudotumor may present with a spectrum of complaints which may include decreased vision, proptosis and painful eye movements. Physical examination and imaging studies were helpful in narrowing the differential diagnosis and proper treatment (Figs. 1 and 2). In contrast to our case, isolated unilateral decreased vision without any other findings except the presence of optic neuritis in a case of orbital pseudotumor has been reported by Patankar et al.⁸ Their patient had presented with an isolated optic nerve inflammatory pseudotumor who had complaints of gradual progressive unilateral loss of vision. That patient showed a dramatic response to a trial of systemic corticosteroids with full recovery of his vision.⁸

Evaluation and management of patients with orbital pseudotumor are challenging and the importance of its inclusion in the differential diagnosis of orbital disorders is necessary.^1–5,7,9 At initial presentation, orbital infections, Grave’s ophthalmopathy and orbital pseudotumor can occasionally demonstrate overlapping clinical features. Orbital pseudotumor is often sub-classified on the basis of the anatomic target areas within the orbit.³ A 10-year retrospective review of 65 patients with orbital pseudotumors treated at the Massachusetts Eye and Ear Infirmary revealed isolated dacryoadenitis (n = 21), isolated myositis (n = 19), concurrent dacryoadenitis and myositis (n = 5), orbital apex syndrome (n = 6), and idiopathic inflammation involving the preseptal region, supra-orbital region, sclera, Tenon capsule, orbital fat or optic nerve (n = 14).⁵

On imaging studies, orbital pseudotumor may present with diffuse orbital mass, uveoscleral thickening, contrast enhancement of Tenon’s potential space, proptosis, thickened extraocular muscles and optic nerve enlargement.^2–5 According to the radiologic and surgical findings, focal mass within the orbit may be the most frequent finding (43%), followed by lacrimal gland enlargement (32%), diffuse orbital inflammation (10%) and myositis (8%); less common findings may be peri-neuritis (2%), scleritis (2%), acute inflammation (2%) and eyelid swelling (1%).^3,9 In addition to scleritis, orbital pseudotumor has been associated with systemic disorders, including rheumatoid arthritis, Crohn’s disease and systemic lupus erythematosis.^3–5,9 An unusual case of orbital pseudotumor presenting with bilateral exudative retinal detachment in a 9-year-old girl has been described. Prompt diagnosis and corticosteroid treatment resulted in good clinical response and significant visual recovery.⁶

Pathogenesis of orbital pseudotumor remains elusive, but infection, autoimmune disorder, and aberrant wound healings have been put forward as possibilities.³ Pathological findings may be non-specific and may only reveal benign lymphoid hyperplasia and inflammatory cell infiltration with necrotizing vasculitis.^2–5 The inflammatory cells comprise non-specific polymorphic, lymphocytic infiltrates with macrophages, polymorphonuclear leukocytes and eosinophils.^2–5 Biopsies obtained from the orbital tissue may show complement deposits and increased expression of HLA class-I antigens in the inter-muscular tissue and the biopsies from pseudotumor cases and Graves’ ophthalmopathy cases contain increased numbers of inter-muscular HLA class-II-expressing cells.^3,10 Proliferating cell nuclear antigen activity in conjunction with the ratio of B-/T-cells may be a helpful immunohistologic adjunct for differentiating purely inflammatory lesions of the orbit from lymphoid tumors.^3,7

Like our patient, systemic corticosteroid therapy is the cornerstone of managing orbital pseudotumors. Improvement with corticosteroid therapy is of diagnostic significance specifically a corticosteroid responsive orbital process is more likely to correspond to pseudotumor.^2–5 Our experience has shown that over 75% of patients show dramatic improvement within 24–48 h of the initiation of systemic corticosteroids. Other associated abnormal laboratory tests may also respond to systemic corticosteroid treatment. Normally, starting dosages of Prednisone 1.0–2.0 mg/kg/day are adequate. When improvement is noted, dosages should be continued with a slow tapering guided by clinical judgment.³ Intra-orbital injection of corticosteroid has been found to be a useful and an effective treatment of orbital pseudotumor and may be considered as a first-line treatment in selected patients.¹¹ Recurrences are common in orbital pseudotumor especially with bilateral disease process. Low-dose radiation may be considered for elderly patients or for those unresponsive to systemic corticosteroids or in whom steroids are contraindicated.^2–5 Other therapies with promises include cytotoxic agents, (Cyclophosphamide and Chlorambucil), immunosuppressants (Methotrexate, Cyclosporine, and Azathioprine), intravenous immunoglobulins, TNF-alpha inhibitor, monoclonal antibody (Infleximab and Adalimumab) and Mycophenolate Moftil.³