Case Presentation: A 59-year-old previously healthy female presented to the emergency department with progressive cognitive decline, psychomotor retardation, and both auditory and visual hallucinations of subacute onset for which she was previously admitted to inpatient care at two separate hospitals. Extensive testing during these admissions were negative for: infection, metabolic derangement, hematologic malignancy, toxins, heavy metals, and illicit drugs. Extensive imaging was ultimately negative for: cerebrovascular ischemia, CNS demyelinating lesions, and tumors. CSF studies were negative for: elevated protein, cell count, IgG, oligoclonal bands, nor anti-neuronal antibodies. Autoimmune serologies showed elevated anti-thyroglobulin and anti-thyroperoxidase antibodies. Neurology was consulted and considered her presentation consistent with Steroid Responsive Encephalopathy with Antibodies to Thyroid (SREAT), also known as Hashimoto’s Encephalopathy. She was started on IVIG and discharged with an oral steroid taper. Two weeks later she presented again to the emergency department for persistent psychiatric and behavioral derangement. She was admitted and started on a repeat IVIG course in addition to high-dose IV steroids, however there was concern for transient worsening of the patient’s neuro-behavioral symptoms.A multidisciplinary review with neurology and psychiatry determined extended-duration steroid and antipsychotic therapy as the most optimal treatment plan. The patient eventually began to demonstrate significant reduction in her psychosis. She was discharged on hospital day ten with an oral steroid taper and antipsychotic medication, olanzapine. Follow up at sixty days post-discharge revealed a return to near-baseline levels of independence without evidence of ongoing psychosis although there was mild residual cognitive impairment on screening examination.

Discussion: SREAT was first described in 1966 by British neurologist Lord W. R. Brain and remains a controversial and poorly understood pathologic entity with an estimated prevalence of 2.1 per 100,000 persons. Given its rarity and protean manifestations it remains a diagnosis of exclusion [1]. SREAT’s most common features include convulsions, memory impairment, speech disorders, motor deficits, and psychiatric symptoms consistent with depression, mania, or psychosis [2]. A key feature of SREAT is its positive response to steroids. However, steroids may also precipitate psychosis in a dose dependent manner [3]. Thus, in certain cases immunosuppressive treatment of SREAT has the potential transiently worsen psychosis in lieu of expected improvement. This may lead to increased diagnostic uncertainty resulting in unnecessary additional testing and lengthy admissions.

Conclusions: Hospitalists must recognize that the treatment for SREAT may result in short term worsening of psychiatric symptoms leading to additional testing as well as a potential loss of trust with family. A multidisciplinary approach may be beneficial in helping to achieve an optimum balance between competing medical interests (ie ‘do no harm’ while also treating the patient). In this case, a continued adherence to high-dose immunosuppression in combination with anti-psychotic therapy was vital to improving patient adherence to medical therapy and ultimately resulting in a positive outcome.