Isolated Faciobrachial Dystonic Seizure in Young Male with LGI1 Encephalitis

Background: LGI1 encephalitis is a rare autoimmune limbic encephalitis characterized memory loss, confusion, temporal lobe seizures and hyponatremia. Less often associated with REM sleep behavior disorder and peripheral nerve hyper-excitability syndrome (Morvan syndrome). Faciobrachial dystonic seizures (FBDSs) are a specific type of focal motor seizure characterized by brief tonic contraction of face, arm/or leg typically alternating sides, and occurring 10 to 100 times a day.

Case Presentation: We report a case of a 37-year-old male who presented to the OPD with a 5-day history of right faciobrachial motor tonic seizure with impaired and frequency up to 30 to 40 times a day without history of fever and headache. Examination findings were unremarkable except for the paroxysmal tightening and jerkiness involving right upper limb and facial region. Initial evaluation showed hyponatremia and MRI brain showed hyperintensity in both medial-temporal lobe with subtle contrast enhancement. Routine CSF testing was normal; and HSV 1 and 2 by PCR were negative. CSF study done on cell-based assay for LGI1 antibodies was positive leading to a diagnosis of LGI1 encephalitis. Before the diagnosis of LGI 1 encephalitis was made, the patient was managed with three antiseizure medications to which he responded poorly. Once the antibody LGI1 came positive, the patient was started on pulse-dose methylprednisolone followed by oral prednisolone and showed significant symptomatic improvement and discharged on oral prednisolone with antiseizure medications.

Conclusion: This case highlights the importance of considering LGI1 encephalitis in the differential diagnosis of even young adults presenting with isolated FBDS as early recognition and treatment can prevent the patient to develop features of encephalitis and therefore better outcomes.

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Artikel online veröffentlicht:
12. September 2024