Abstracts

Rationale: Extreme delta brush (EDB) pattern is predominantly associated with anti-N-methyl D-aspartate receptor (NMDAR) encephalitis. Emerging literature, however, has shown that it is seen in other autoimmune encephalopathies as well. Here, we present a pediatric case of Hashimoto’s encephalitis with this unique electrographic signature. Hashimoto’s encephalitis has in the past been shown to have non-specific changes on electroencephalogram (EEG) including slowing and possible ictal patterns. No previous case of delta brush associated with Hashimoto’s encephalitis has been published. Methods: A systematic review was completed of the delta brush pattern in encephalitis, and separately of Hashimoto’s encephalitis was performed using PubMed.  Search results were reviewed for incidents of delta brush pattern, along with the type of encephalitis.  Reports of Hashimoto’s encephalitis were reviewed for common EEG patterns noted.  One pediatric case of a 14-year-old female from our institution was reviewed.  Patient had no significant past medical history who presented to an outside facility with several days of headache and blurred vision, followed by new-onset seizures. She was transferred after being given lorazepam and started on levetiracetam and acyclovir.  On exam, she was found to be hypertonic and poorly responsive, without further focal features. She subsequently became febrile, demonstrated clonus on exam, and required intubation due to concern over airway protection. Results: Initial studies included Magnetic resonance imaging of her brain, cerebrospinal fluid analysis, and infectious disease screening, all of which were unremarkable. Autoimmune encephalopathy panel was also collected (eventually negative), with EEG revealing an EDB pattern without further electroclinical seizures. following admission. She was empirically started on methylprednisolone 1 gram/day (patient 73.7 kg) with rapid improvement.  Thyroid studies revealed a thyroid-stimulating hormone level of 2.59 uIU (0.35-4.94 uIU) and free thyroxine level of 0.6 ng/dL (0.7-1.5 ng/dL). Anti-thyroperoxidase (TPO) antibodies resulted at 534 IU/ml (0-26 IU/ml) and anti-thyroglobulin antibody was>2250 IU/ml (0-0.9 IU/ml). By established criteria, she was diagnosed with Hashimoto’s encephalitis based on an elevated plasma anti-TPO antibody level, favorable response to corticosteroid therapy, acute to subacute onset of encephalopathy, and a lack of an alternative etiology. Conclusions: While EDB is most commonly seen in anti-NMDAR encephalitis, we present a unique case of EDB in Hashimoto’s encephalitis. This further supports the notion that EDB is a potential biomarker for autoimmune encephalitis which, in the proper context, should warrant consideration of earlier treatment with corticosteroids. Funding: None