Agrypnia excitata: a clinical biomarker of acute relapse in anti-NMDAr encephalitis.

Sleep disorders have been described in anti-NMDAr encephalitis including insomnia, hypersomnia, narcolepsy, and sleep-disordered breathing. A patient presented with typical features of anti-NMDAr encephalitis associated with a right ovarian teratoma. After two months of clinical improvement with immunotherapy, the patient deteriorated. A 24-hour video EEG-polysomnography revealed a severe sleep quantity deficit, a total destruction of sleep architecture consisting of short clusters of N1 and rapid eye movement sleep stages, associated with motor and autonomic hyperactivity. These features were consistent with agrypnia excitata and were associated with disease reactivation due to a left ovarian teratoma. A new course of immunotherapy and surgery improved clinical symptoms and normalized sleep patterns. Agrypnia excitata, the most severe form of status dissociatus, was a sleep biomarker of disease relapse in this patient. Polysomnographic studies in the acute phase of anti-NMDAr encephalitis are lacking and are needed to better understand the evolution of sleep patterns.