A Pediatric Case of LGI1 Autoimmune Encephalitis Presenting with Faciobrachial Dystonic Seizures
Cheryl Fields1, Nagma Dalvi1, Susan Duberstein1, Donya Eizadkhah1, Solomon Moshe1
1Child Neurology, Childrens Hospital at Montefiore
Objective:
NA
Background:
15-year-old male presented with acute behavioral changes (agitation, confusion, declining grades), frequent falls, and abnormal movements involving the right corner of the mouth, cheek, arm and hand. His lower face appeared to be pulling to the right with concomitant flexion of the ipsilateral elbow and wrist in a motion that brought his hand close to his face
Design/Methods:
NA
Results:
Continuous EEG demonstrated approximately 70 seizures with either right or left rhythmic delta activity and superimposed spikes with associated twitching or dystonia in the contralateral arm or hand. MRI imaging showed T2 hyperintensity of the left hippocampus and amygdala. His seizures were controlled after loading 3 ASM's (lacosamide, levetiracetam, valproate)  followed by IVIG and methyl prednisolone administration. The diagnosis was confirmed by Mayo autoimmune encephalitis panel that was positive in the CSF and serum for LGI1 (leucine-rich glioma-inactivated 1) antibody.  
Conclusions:
LGI1 autoimmune encephalitis is the second most common autoimmune encephalitis after NMDA(N-Methyl-D-aspartate).  It is most commonly seen in middle aged men and estimated to occur in 0.83 per million. LGI1 autoimmune encephalitis is associated with multiple seizure types including focal seizures and tonic clonic seizures. The most distinctive feature of LGI1 autoimmune encephalitis is faciobrachial dystonic seizures that have been reported extensively in adult patients. LGI1 autoimmune encephalitis with seizures is exceedingly rare in the pediatric population. We found only 6 reported cases. Our case is the first reported faciobrachial dystonic seizures at presentation in a pediatric patient.  
10.1212/WNL.0000000000202690