Abstracts

Rationale: Steroid-responsive Encephalopathy with Autoimmune Thyroiditis (SREAT) can present in many ways including cognitive or behavioral changes, psychosis, stroke-like signs, tremor, myoclonus, stupor and seizures. Seizures can be focal motor, tonic, generalized tonic clonic and myoclonic in type. Given the increasing recognition of inflammation in seizures and epilepsy, as well as the association of seizures and epilepsy with inflammatory disorders, we report a case of epilepsia partialis continua (EPC) as the presenting manifestation of SREAT. Methods: A 62 year old lady with hypothyroidism on levothyroxine treatment was transferred from an outside hospital for several weeks of repetitive myoclonic movements of the right hemi-body. Consciousness was preserved and there was no involvement of the left side. Continuous video Electroencephalography (cVEEG) showed frequent left centroparietal periodic sharp waves, temporally related to the myoclonic jerks as well as intermittent focal seizures over the same region. Anti-epileptic drug therapy including levetiracetam, dilantin, and klonopin resulted in no clinical or electrographic changes. Results: Magnetic Resonance Imaging (MRI) of the brain revealed diffuse white matter changes without enhancement, as well as restricted diffusion along the left sensorimotor cortex. Cerebrospinal fluid testing showed mild pleocytosis (WBC 16, RBC 340 with normal protein). Extensive laboratory testing was significant for an elevated thyroid stimulating hormone (TSH- 9.24 uIU/ml). The patient was started on intravenous high-dose steroids for possibility of a steroid-responsive encephalopathy. By the second day of steroid treatment, she showed significant decrease in the repetitive myoclonic movements. The abnormal movements ceased by the third day of steroid treatment. The patient was discharged on a prednisone taper, and her thyroperoxidase (TPO) antibody returned as positive (165.1 U/ml) prior to discharge.Conclusions: We report a case of steroid-responsive encephalopathy with autoimmune thyroiditis presenting as EPC. Our case highlights the importance of considering autoimmune etiologies in refractory seizures including EPC, because there is a therapeutic benefit that can be offered with high-dose corticosteroids.