New onset steroid-responsive Hashimoto's encephalopathy in the older population: a scoping review

Hashimoto's encephalopathy (HE) is a rare autoimmune disorder which can mimic late-life neuropsychiatric symptoms as part of a dementia syndrome. Our objective was to review the clinical profile and management outcomes of new onset HE in older adults based on available literature.

We conducted a comprehensive search for studies on patients aged 65 years and older with newly diagnosed HE across multiple databases, including Medline, Web of Science, Wiley Online Library, and The Cochrane Library, covering publications up to January 2024. Clinical information was extracted and analyzed using Descriptive statistics.

Out of 608 articles screened, 45 articles detailing 51 patients were included. Majority of older patients (n = 48, 94.1%) were initially treated with steroids. Methylprednisolone 1 g/day was given in 37.2% (n = 19) for a minimum of 3 days before tapering. Some initiated a reduced dose of 500 mg/ day (n = 5, 9.8%) with similar outcomes. Response is favorable, with 56.8% (n = 29) returning to near baseline functional status, while 29.4% (n = 15) showed partial improvement.

Evidence from 51 cases highlight the disorder's variable course in the older population; often mimicking other age-related conditions leading to diagnostic challenges and delays in management. A tailored approach is required, balancing the benefits of immunomodulatory therapies with potential risks. Further research is essential to understand the mechanism of HE in the older population and enhance patient outcomes by developing standardized treatment protocols tailored to this vulnerable population.