Opsoclonus-myoclonus syndrome in anti-N-methyl-D-aspartate receptor encephalitis

Abstract

Background: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis has been recently reported as autoimmune/paraneoplastic encephalitis, affecting mostly young females.

Objective: To describe opsoclonus-myoclonus syndrome in association with anti-NMDAR antibodies.

Design: Case report.

Setting: Geneva University Hospital. Patient A 23-year-old woman with opsoclonus-myoclonus syndrome.

Results: Two weeks after an episode of gastroenteritis, the patient developed symptoms of depression associated with psychomotor slowing, progressive gait instability, and opsoclonus-myoclonus. Cerebrospinal fluid examination showed mild lymphocytic pleocytosis and intrathecal IgG synthesis with oligoclonal bands. The patient's condition worsened rapidly to an akinetic mutism, followed by a period of agitation, delirium, and hallucinations. These gradually subsided; however, a frontal behavior and executive dysfunction persisted 5 months after symptom presentation. No tumor was found. Anti-NMDAR antibodies were found in the cerebrospinal fluid.

Conclusions: Opsoclonus-myoclonus may occur in patients with anti-NMDAR encephalitis. Prompt diagnosis of this disorder is important because after tumor removal and immunomodulatory therapies it has a relatively good prognosis.

Figure

Electroencephalography of a 23-year-old woman with opsoclonus-myoclonus syndrome. A, Recording on day 10 shows bursts of diffuse delta activity on a background of theta rhythm. The first marker indicates eye closure; the second marker, eye opening. B, Recording on day 60 shows a normal alpha activity with ocular artifacts in the frontopolar leads; the electrocardiogram shows tachycardia (100 beats/min). The marker indicates eye closure.