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Abstract Details

Hashimoto Encephalopathy Presenting with Seizures and Uncommon EEG pattern - Case Report
Epilepsy/Clinical Neurophysiology (EEG)
P9 - Poster Session 9 (5:30 PM-6:30 PM)
Hashimoto encephalopathy (HE) or Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is a rare and controversial disorder, presenting with subacute neuropsychological symptoms and associated with elevated antithyroid antibodies.
Not applicable

Case Presentation: 60-year-old female with a past medical history of hypertension, hyperlipidemia, and colon cancer, presenting with a focal seizure cluster - left gaze deviation and left greater than right hemibody tonic-clonic activity. The evaluation included an EEG which revealed bifrontal (left greater than right) slowing as well as bifrontal sharp waves (again left greater than right) which at times occurred in a quasi-periodic fashion. Serum thyroperoxidase antibodies were high (81.5). Sedimentation rate, CRP, and ANA were also elevated.  CSF showed lymphocytic predominant pleocytosis (73), slightly elevated protein (51), normal glucose, and negative infectious and autoimmune panels. MRI brain revealed subtle indistinctness of the CSF adjacent to the right frontal lobe (anterior pole) and subtle pial enhancement. The thyroid gland was enlarged. The patient was treated with IVIG followed by IV methylprednisolone, with clinical improvement and resolution of EEG and MRI abnormalities. Several months after the initial presentation she developed subclinical hypothyroidism with elevated TSH.

Not applicable
EEG abnormalities in SREAT are very common (90-98%) but nonspecific. Most frequently EEG abnormalities include generalized slowing and GRDA (70%). Focal slowing, triphasic waves, and focal sharp waves occur less frequently. Even more rarely repetitive focal spikes/sharp waves, focal or generalized status epilepticus, and myoclonic seizures are seen. Resolution of EEG changes may parallel the clinical improvement with treatment although non-specific changes were still present in our patient despite treatment.  Epileptiform patterns in SREAT are not well described in the literature and may not correlate with imaging findings. We are presenting a case of SREAT with associated focal and periodic discharges, an uncommon finding in this condition. 
Hasmik Amirjanyan, MD
Dr. Amirjanyan has nothing to disclose.
Shivanee Sodani, MBBS Dr. Sodani has nothing to disclose.
Musab Zorlu, MD Dr. Zorlu has nothing to disclose.
Jose Antonio Montes-Rivera, MD, FAAN (UConn Health) Dr. Montes-Rivera has nothing to disclose.
Marie C. Eugene, DO (University of Connecticut Health Center) Dr. Eugene has nothing to disclose.