Optic neuritis associated with anti-NMDA receptor antibody in the remission phase of anti-NMDA receptor encephalitis

Optic neuritis associated with seronegative autoimmune encephalitis: a case report

Optic neuritis is an inflammatory demyelinating disorder that primarily affects the optic nerve and is often associated with multiple sclerosis. While it is rare for optic neuritis to be accompanied by autoimmune encephalitis, it can occur in some cases. A 65-year-old woman with bipolar disorder presented with a progressively altered mentality. Magnetic resonance imaging of the brain showed no definite abnormal findings. Electroencephalography revealed nonconvulsive status epilepticus. Cerebrospinal fluid study and autoimmune and paraneoplastic encephalitis antibodies were negative. The patient was diagnosed with seronegative autoimmune encephalitis and treated with methylprednisolone, intravenous immunoglobulin, and rituximab. Her condition gradually improved except for persistent blindness on the left side. This case highlights the importance of considering autoimmune encephalitis even in the absence of identifiable pathogenic antibodies when clinical manifestations and response to immunotherapy support such a diagnosis.

Atypical Optic Neuritis: The Potential Red Flags

BACKGROUND

Many potential causes of optic nerve inflammation exist, including typical and atypical causes, which require different management strategies.

OBJECTIVE

The objective of this study is to identify red flags that help differentiate typical from atypical optic neuritis (ON).

MATERIALS AND METHODS

This prospective study included 66 patients (100 eyes) with immune-mediated ON from January 2016 to June 2019, carefully excluding the nonimmune causes. The clinico-radiological features, investigations, therapy, and outcome were analyzed.

RESULTS

We evaluated 33 cases each of typical and atypical ON. The typical group included 29 idiopathic ON and four associated with multiple sclerosis. Atypical ON included 19 neuromyelitis optica (NMO), seven MOG-associated ON (MOG-ON), and others due to Sjogren's syndrome, granulomatous polyangiitis, sarcoidosis, and IgG4 disease. Atypical ON occurred significantly and more frequently with extremes of ages (<10 or >70 years), bilateral simultaneous or severe vision loss with early disc pallor, multiple attacks, symptoms/neuro-imaging indicating non-MS disease e.g., long segment ON/myelitis, large confluent lesions, the involvement of optic tract, chiasma, area postrema or diencephalon, and (pachy) meningitis. Systemic involvement and poor outcomes despite steroids and second-line immunosuppression were observed more often in the atypical ON.

CONCLUSIONS

The red flags indicating atypical ON are onset at extremes of age, multiple attacks, bilateral simultaneous or severe to very severe vision loss, early disc pallor, neurological symptoms, or imaging abnormalities suggesting non-MS disease, systemic involvement, and poor steroid responsiveness. The awareness might help the clinician promptly identify and escalate therapy to ensure a better outcome.

Recurrent Optic Neuritis in Paediatric Anti-N-Methyl-D-Aspartate Receptor (Anti-NMDAR) Encephalitis: Case Report and Literature Review

Optic neuritis associated with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis poses a novel challenge and is recognised as being part of overlapping antibody-associated demyelinating syndromes. We report a case of a 10-year-old girl who first presented with anti-NMDAR encephalitis and later developed four episodes of left optic neuritis. Blurring of vision, pain on eye movement, and headache were the striking features in all episodes of optic neuritis. For each recurrent episode of optic neuritis she was treated with intravenous methylprednisolone, following which visual acuity, colour vision, and visual field improved to normal. Neuroimaging was unremarkable. Myelin oligodendrocyte glycoprotein and aquaporin-4 antibody tests were negative. She developed a relapse of anti-NMDAR encephalitis after recurrent episodes of optic neuritis despite being on azathioprine. Intravenous immunoglobulin and cycles of cyclophosphamide were started, and she has been free from optic neuritis and encephalitis for more than one year since. Optic neuritis and anti-NMDAR encephalitis are reversible with intensive immunotherapy. Early and accurate diagnosis can lead to better management of this condition.