Encéphalite limbique avec anticorps anticanaux potassiques voltage dépendants et troubles sévères du sommeil

Abstract

Introduction Voltage-gated potassium channels (VGKCs) antibodies are associated with neuromyotonia, limbic encephalitis and Morvan syndrome. Case report We report the case of a patient who, after three weeks of fever, presented an anamnestic syndrome, associated with confusion and partial seizures. MRI showed left hyperintensity of mesial temporal structures on Flair images and right hippocampal atrophy on T1 weighted sequences. Laboratory tests only showed high level of anti-TPO antibodies. Thus, the patient was considered as having Hashimoto's encephalopathy. She was treated with intravenous methylprednisolone with no improvement of symptoms. On the contrary, the patient suffered from insomnia, deep diurnal drowsiness and complete disappearance of REM sleep. Episodes of hypothermia and severe hyponatremia were recorded. Serum VGKC antibodies were found at high level. After intravenous immunoglobulin treatment followed by methylprednisolone, we noted remarkable improvement of clinical status. Polysomnography showed reappearence of REM sleep. Conclusion This case report broadens the spectrum of clinical manifestations associated with VGKC antibodies and suggests that VGKC are implicated in regulation of sleep. The potential pathophysiological mechanisms linking sleep disturbances and VGKC antibodies are discussed.