Key takeaways:

• Researchers enrolled 188 patients with rapidly progressive dementia, three of whom were identified as abrupt onset.
• Screening for abrupt-onset dementia should consider vascular, toxic/metabolic, autoimmune and structural disorders.

DENVER — While rare and associated with a limited differential diagnosis, abrupt-onset dementia may be treatable with prompt recognition and early intervention, according to a poster at the American Academy of Neurology annual meeting.

“The research was based on a few cases we had in a different cohort, who manifested with dementia within a few hours and we wanted to find the reason for it,” Yoav Piura, MD, a postdoctoral fellow in the department of neurology at the Mayo Clinic in Jacksonville, Florida, told Healio.

Seeking to determine the frequency and causes of abrupt-onset dementia, Piura and colleagues sought to refine the concept by examining clinical characteristics, etiologies and treatability, given prior research established only a guideline for those with sharp declines in cognitive function.

They conducted a prospective observational study from February 2016 to September 2023 and included 188 individuals with rapidly progressive dementia (with those logging 7 or fewer days from first symptom to onset of RPD labelled as abrupt onset) at the Mayo Clinic in Florida as well as Washington University in St. Louis.

Researchers also performed a review of existing literature to aid their understanding of causes and long-term outcomes associated with the condition, and identified 55 cases from 47 articles.

According to results, three patients in the analysis cohort met criteria for abrupt-onset dementia, with brain MRI demonstrating lesions associated with autoimmune and vascular causes, including acute infarction and restricted diffusion.

Of the 55 cases analyzed in the literature review, causes of abrupt-onset dementia included vascular (n = 24), toxic/metabolic (n = 14), autoimmune/inflammatory (n = 12) and structural (n = 5) disorders. In addition, brain MRI lesions within Papez circuit structures were common among affected patients, with most lesions identified in the hippocampus and fornix.

Early recognition of patients with treatment-responsive causes may lead to early intervention and improved outcomes, researchers wrote.

“Clinical relevance goes in two ways: the first is for understanding the syndrome and what causes it,” Piura said. “The other one is to understand if it’s treatable, and if so, how can we do it and benefit the people who suffer from it.”