Rare case of isolated optic neuritis due to systemic lupus erythematosus (SLE)

Dear Editor,

We want to share a unique clinical presentation observed in our practice that highlights the importance of a detailed evaluation of the wide spectrum of causes leading to optic neuritis. In this case, SLE presented as an isolated optic neuritis (ON).

ON is characterized by inflammation of the optic nerve, causing varying degrees of vision loss. The mechanisms underlying optic neuritis are diverse and can include either demyelinating or axonal damage due to infections, immune-related conditions, toxins, or paraneoplastic disorders¹. Neuro-ophthalmic manifestations of SLE are rare, with a prevalence of 3.6%², and only 1% of patients have optic nerve or optic chasmal involvement^3,4. Optic neuritis described in lupus patients can present as acute or progressive, painless or painful vision loss, depending on the location of the pathology. The etiology of optic nerve involvement varies from demyelination to vaso-occlusive disease and axonal necrosis. We encountered a 48-year-old female patient presenting with a history of subacute onset, progressive, painless visual loss over the past year without any history suggestive of infective, toxic, or immune-related illnesses. The patient’s vision was severely impaired, which was reduced to hand movements and counting fingers at a distance of 1 foot. Ophthalmological examination revealed bilateral optic disc pallor, indicative of optic atrophy, and bilateral pupillary responses were sluggish. The rest of the neurological examination was noncontributory.

MRI revealed attenuation of retrobulbar segments of bilateral optic nerves with altered signal intensity over an approximate 1.3 cm long segment. VEP demonstrated bilateral prolonged P100 latency, with 127 ms in the right and 126 ms in the left eye. The patient tested positive for anti-nuclear antibody (ANA) by the immune-fixation (IF) method, showing a speckled pattern with a titer of 1:200. The serum neuromyelitis optica-myelin oligoclonal glycoprotein (NMO-MOG) panel was negative. Oligoclonal bands (OCBs) were positive in both serum and CSF, indicating a systemic autoimmune disease process.

Anti-Smith antibody levels measured by enzyme-linked immunosorbent assay (ELISA) were positive with a value of 40.79 (>20 being positive), showing a specificity of 96–98% for SLE. Additional investigations revealed low C4 and normal C3 levels. The retinal nerve fiber layer (RNFL) of the optic nerve was also thinned. Thus, these findings confirm the diagnosis of bilateral optic neuritis secondary to SLE, presenting as an isolated syndrome.

SLE-related ON follows a different course and requires distinct management compared to idiopathic or other autoimmune-related ON⁵. The prognosis and visual outcomes in SLE-related ON are directly influenced by specific and prolonged treatment compared to primary demyelinating insult. Timely identification of the disease and early treatment are crucial for achieving better visual outcomes and improving prognosis.

This case highlights the importance of considering vasculitis as a differential diagnosis for bilateral painless visual loss apart from demyelinating causes. A thorough vasculitis workup should be a mandatory part of the diagnostic process. Timely administration of appropriate immunosuppressive drugs can help prevent further damage and potentially aid in the recovery of vision loss.