Recurrent and Reversible, Bitemporal Field Defect from Presumed Chiasmitis in a Patient with Systemic Lupus Erythematosus

ABSTRACT

Systemic lupus erythematosus (SLE) is a chronic, recurrent and remitting autoimmune disease affecting mostly women and presenting between late adolescence and the fourth decade of life. Ocular manifestations may occur in one-third of patients with SLE, with keratoconjunctivitis sicca as the most common and optic nerve and retina abnormalities as the most severe. Neuro-ophthalmological manifestations occur in approximately 1% of patients with SLE, usually in the form of optic neuropathy. The purpose of this paper is to describe a patient who developed recurrent optic chiasmitis as an uncommon sign of disease activity in SLE.

Case report

A 29-year-old female was referred for ophthalmic evaluation because of the sudden onset of headache and blurred vision in both eyes (OU) upon awakening. The patient had a 3-year history of SLE diagnosed because of non-erosive arthritis, lymphopaenia and raised levels of anti-Sm and antinuclear antibodies. At presentation, systemic findings appeared to indicate the disease was under control with the use of acetylsalicylic acid, azathioprine and belimumab.

Upon ophthalmic examination, the best-corrected visual acuity (VA) was 20/150 in OU. Slit-lamp examination, tonometry, funduscopy and ocular motility findings were unremarkable. Optical coherence tomography (OCT) revealed peripapillary retinal nerve fibre layer and macular thickness measurements within normal limits. The pupils were equal in size and reacted sluggishly to light OU. Visual field (VF) examination showed bitemporal field loss, indicative of a chiasmal lesion (Figure 1a). Laboratory findings revealed only a mildly elevated erythrocyte sedimentation rate (36 mm/hr). Anticardiolipin and anti-aquaporin 4 antibodies were negative. The cerebrospinal fluid analysis was normal and no abnormalities were observed on magnetic resonance (MR) imaging (Figure 2) or MR angiography. Intravenous methylprednisolone was administered (1 g/day for three days), followed by significant visual improvement. Two weeks later, the VA was 20/25 OU and the VF was normal (Figure 1b). Subsequently, the patient was treated with monthly cyclophosphamide pulse therapy and oral prednisone for six months. After this period, cyclophosphamide was discontinued while oral prednisone was maintained (60 mg per day).

Figure 1.

Automated perimetry using the Humphrey 30–2 SITA standard test. (a): upon presentation, showing bitemporal hemianopia; (b): after first treatment, with normal findings; (c): upon recurrence of chiasmal involvement, showing inferior bitemporal field loss; and (d): after retreatment, with complete visual recovery

Figure 2.

Magnetic resonance imaging at the time of the first episode of visual loss, with no chiasmal changes. Left, T2-weighted image; Right, T1-weighted, contrast-enhanced image

One month later, while still on prednisone therapy, the patient complained of recurrent headache and bitemporal VF loss (Figure 1c). MR imaging (MRI) was again completely normal. Intravenous methylprednisolone and cyclophosphamide treatment were administered for three days, with marked improvement of headache and vision (Figure 1d). A repeat OCT scan was unchanged from the first examination. Despite the absence of any other manifestation of SLE, the occurrence of two episodes of optic chiasm-related visual loss indicated disease activity. The introduction of mycophenolate mofetil (1.5 g/day) combined with prednisone (20 mg/day) provided apparently adequate control, with no recurrence in the subsequent two-year follow-up period.

Discussion

Optic nerve involvement is uncommon in SLE. When it does occur, clinical manifestations are variable, including anterior ischaemic optic neuropathy, posterior ischaemic optic neuropathy, papillitis and retrobulbar optic neuritis, presumably as a result of an autoimmune-induced vaso-occlusive disease mechanism.^1–5 Chiasmal involvement, on the other hand, is extremely rare, with only eight cases reported in the literature. Our case is interesting, not only because of the chiasmal inflammation but also because the patient experienced two similar episodes eight months apart.

While the differential diagnosis of optic chiasm-related visual loss is most often due to suprasellar mass lesions, chiasmal inflammation is in itself a well-recognised condition in the literature and may be idiopathic, associated with granulomatous infiltration (tuberculosis, sarcoidosis, anti-neutrophil cytoplasmic antibody-positive vasculitis), lymphocytic inflammation, demyelinating diseases (idiopathic optic chiasmitis, multiple sclerosis, neuromyelitis optica) or histiocytic infiltration (xanthomatous hypophysitis and mucoceles of the paranasal air sinuses).⁶ All of these conditions were ruled out during clinical and laboratory investigations.

Although our patient presented normal MRI findings, in some previous SLE cases with optic pathway involvement, MRI showed enhancement or enlargement from the intraorbital optic nerve to the optic tract.^7,8 However, absence of abnormality on MRI has also been observed in previous cases of visual loss associated with SLE. In an MRI analysis of six SLE patients with vasculitis-related optic neuropathy, three patients had normal image findings.⁷ Also, Kawasaki and Purvin reviewed 20 cases of idiopathic chiasmal neuritis, three of which had normal MRI findings.⁸ Chiasmal involvement in SLE usually responds well to corticosteroid therapy⁹ and many achieve complete recovery, although severe permanent vision loss has also been reported.^10–12 In our patient, despite the absence of clinical complaints between the two episodes, the occurrence of visual loss suggests the disease was not well controlled.

The current case is relevant in that it describes optic chiasm involvement as a manifestation of SLE and the possibility of recurrence if the disease is not completely controlled. Awareness of this outcome is important for early recognition and adequate treatment, potentially preventing permanent visual loss.

Declaration of interest statement

The authors declare no conflict of interest.