Authors :
Presenting Author: Jamie Cheng, BA – The Warren Alpert Medical School of Brown University
Gabrielle Lindley, MD – The Warren Alpert Medical School of Brown University
seo Youn Chang, MD – The Warren Alpert Medical School of Brown University
Julie Roth, MD – The Warren Alpert Medical School of Brown University
Rationale:
Faciobrachial dystonic seizures (FBDS) are characteristic early features in leucine-rich glioma inactivated-1 antibody (LGI1) encephalitis. However, atypical features such as continuous and episodic leg movements (crural features); basal ganglia MRI changes; and preserved cognition can cloud initial diagnosis. This case highlights an atypical presentation within the clinical-radiographic spectrum of LGI1 autoimmunity, FBCDS.Methods:
With verbal and written consent, a 69-year-old male with history of diabetes mellitus presented with two months of brief (10–15 sec), recurrent episodes of unilateral facial grimacing and ipsilateral arm dystonia, and alternating sides (à bascule), occurring every 5–10 minutes, with speech arrest. He also described nearly continuous, bilateral leg movements while awake, along with transient leg weakness recently leading to a fall. Cognition was normal.Results:
Continuous video-EEG showed no electrographic correlate during FBDS or crural episodes (Figure 1); bitemporal slowing was observed interictally. Serum sodium of 128-131 mmol/L (normal 135–145 mmol/L) was noted. MRI revealed symmetric T2 hyperintensities in the bilateral basal ganglia (Figure 2), an unusual finding in LGI1 encephalitis. LGI1 antibodies were elevated in CSF (1:160, normal < 1:10) and serum (1:2560, normal < 1:10), confirming LGI1 autoimmune encephalitis. Immunotherapy with IV methylprednisolone (1g/day x5 days) followed by IVIG (0.4 g/kg/day x3 days) resulted in near-immediate resolution of the crural motor episodes and marked improvement of the FBDS episodes, for which baclofen was added.