SUN-LB099 Hashimoto's Encephalopathy: The Needle in the Haystack

Abstract

Background: Hashimoto’s encephalopathy (HE) is a rare heterogeneous disorder first described in 1966 and presents with variable neuropsychiatric dysfunction, including cognitive decline, seizures, myoclonus, and psychiatric manifestations. HE is likely an autoimmune vasculitis rather than a thyroid dysfunction, and is steroid responsive. Clinical case: A 64-year-old Caucasian female with a past history of tobacco abuse presents with altered level of consciousness, left frontal headache, and a mechanical fall resulting in a radial fracture. No chest pain or syncopal episode. She was noted to have persistent confusion and flu-like symptoms for three days. Review of systems were otherwise negative. Patient does not take any medications. Surgical and social histories were unremarkable. Vital signs: BP 131/59, HR 97, RR 16, Tmax 103.4, Sat 97%. Neurologic examination revealed episodes of confusion with paraphasic speech errors. She was unable to correctly recall her name. No dysarthria, facial asymmetry, or motor deficits. Laboratories: WBC 19,100uL (4,000-10,000uL). Chemistries revealed normal electrolytes and hepatic function, coagulation studies, urinalysis, B12, TSH, and toxicology. Autoimmune and paraneoplastic etiologies were excluded. Lumbar puncture revealed elevated protein 102.7mg/dL (15-45mg/dL) and WBC 54/uL (0-10/uL) with 100% mononuclear predominance. Head CT revealed low attenuation in the right posterior temporal lobe. MRI brain without/with contrast revealed chronic ischemic vessel disease. EEG noted mild generalized slowing and disorganization. Patient was initially treated for viral encephalitis until CSF PCR analyses for a broad spectrum of pathogens was negative. Further serum studies including thyroglobulin antibody and thyroid peroxidase antibody were sent, noting values of 63.8U/mL (<60U/mL) and >1300U/mL (<60U/mL), respectively. She was treated with Methylprednisolone 250mg IV daily for three days and transitioned to a Prednisone 60mg daily taper. She had immediate and complete resolution of her symptoms within the first 24 hours of corticosteroid therapy. Conclusion: Hashimoto's encephalopathy is a diagnosis of exclusion as it can mimic meningitis, encephalitis, psychiatric disorders, stroke, vasculitis, and migraines. Persistent confusion and fevers may cause a delay in diagnosis. HE affects women predominantly in the 5-6th decade. Diagnosis can be made with an elevated anti-thyroid peroxidase antibody and/or antithyroglobulin antibody. Severity does not correspond with serum levels. HE responds well to corticosteroids, including 50-150mg Prednisone daily, with 90-98% response rate, and may take months for complete resolution of symptoms. Refractory cases may require immunosuppressive agents. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.