Abstract
Introduction: Antibodies against N-methyl D-aspartate receptor (anti-NMDAR) are directly pathogenic autoantibodies associated with encephalitis. Cases reporting the presence of anti-NMDAR antibodies associated with a demyelinating disease have been published, some without symptoms of NMDAR encephalitis.
The aim of our study was to describe characteristics of a demyelinating disease in patients with anti-NMDAR antibodies. Material and methods: Anti-NMDAR antibodies were investigated in the serum and cerebrospinal fluid of patients with clinically suspected autoimmune encephalitis by indirect immunofluorescence using cell-based assay on fixed cells transfected for the antigen.
The clinical course and MRI findings consistent with a demyelinating disease were assessed in accordance with the current diagnostic criteria. Results: Eleven patients with autoimmune encephalitis and positive anti-NMDAR were identified between 2012 to 2015.
Ten of them met criteria of NMDAR encephalitis, one patient had an acute onset (de novo status epilepticus) with MRI and CSF findings corresponding with acute disseminated encephalomyelitis and regression following corticosteroid treatment. Subsequently, due to MRI dynamics, this patient met the criteria of multiple sclerosis.
One patient with NMDAR encephalitis developed an optic neuritis 20 months later and MRI showed demyelinating changes with dissemination in time and space. Following corticosteroid and azathioprine treatment, the patient is clinically stable but with persisting MRI disease activity.
In both patients, demyelinating lesions were also identified in the spinal cord. Conclusion: In patients with an atypical manifestation of a demyelinating disease (prominent psychiatric or cognitive symptoms, seizures or extrapyramidal signs) anti-NMDAR testing should be performed and an appropriate immunotherapy should be started in positive cases.
In some patients, NMDAR encephalitis may result in an onset of a demyelinating disease.