Abstracts

Rationale: The term “cyclic seizures” refers to a pattern of seizures recurring at regular time intervals and has been recently described predominantly in older, critically ill patients with acute or progressive brain injury.  Little information is available about the occurrence of cyclic seizures within the pediatric population.   Here, a case of cyclic seizures is described in a previously healthy 18-year old female with leucine-rich glioma-inactivated 1 (LGI1)-antibody limbic encephalitis.  This condition is associated with faciobrachial dystonic seizures which often lack an ictal surface EEG correlate. Methods: Initial continuous EEG interpretation was performed at the time of patient presentation.  The EEG was subsequently reanalyzed to identify trends not immediately evident by standard visual analysis.  A retrospective chart review was performed for clinical details including the patient’s clinical outcome. Results: The 18-year-old female initially presented to an outside hospital for headache followed by episodes concerning for seizure.  Events of concern consisted of twitching of the face and stiffening of extremities sometimes associated with alteration of awareness.  The patient gradually developed worsening mentation with intermittent confusion, memory impairment, and visual hallucinations evident even in the absence of any abnormal movements.  Initial neuroimaging, CSF studies, and routine EEG at the outside hospital were reportedly unremarkable and she was discharged with a diagnosis of psychogenic non-epileptic events.  Two weeks after symptom onset, she presented to our hospital for continued abnormal movements and changes in mental status.  She was somnolent but able to follow commands and answer questions appropriately.  EEG showed an age appropriate occipital dominant rhythm but had increased delta and theta frequency activity present in multiple brain regions.  Rare epileptiform discharges were seen in the right frontal region.  Numerous seizures lasting seconds in duration were recorded occurring cyclically every 1-2 minutes which consisted predominantly of myoclonus of the face and/or extremities (lower extremities more commonly involved than the upper extremities).  Less commonly brief periods of alteration of awareness were also seen.  Improvement in seizure burden was seen following administration of anti-epileptic medications.  MRI showed T2 changes in the right frontal operculum, right mesial temporal lobe, and bilateral hippocampi and cingulate gyri.  CSF was positive for elevated LGI1 antibodies.  Treatment included IV steroids, plasma exchange, IVIG, and rituximab with clinical improvement.  Seizures became well controlled within 2 months and routine EEG normalized shortly thereafter.  Less than 1 year after presentation, the patient performs all activities of daily living independently and has returned to school with some modifications. Conclusions: LGI1-antibody limbic encephalitis can be associated with cyclic faciobrachial dystonic seizures in the pediatric population.  Recognition of these seizures can be complicated by lack of a consistent ictal correlate on surface EEG.  While cyclic seizures tend to be associated with worse prognosis in older adults, this teenage patient has responded well to treatment, suggestive that age of onset and underlying etiology may be of prognostic significance.   Funding: Not applicable