This article presents a practical and informative approach to the evaluation of a patient with a rapidly progressive dementia (RPD).
Prion diseases are the prototypical causes of RPD, but reversible causes of RPD might mimic prion disease and should always be considered in a differential diagnosis. Aside from prion diseases, the most common causes of RPD are atypical presentations of other neurodegenerative disorders, curable disorders including autoimmune encephalopathies, as well as some infections, and neoplasms. Numerous recent case reports suggest dural arterial venous fistulas sometimes cause RPDs.
RPDs, in which patients typically develop dementia over weeks to months, require an alternative differential than the slowly progressive dementias that occur over a few years. Because of their rapid decline, patients with RPDs necessitate urgent evaluation and often require an extensive workup, typically with multiple tests being sent or performed concurrently. Jakob-Creutzfeldt disease, perhaps the prototypical RPD, is often the first diagnosis many neurologists consider when treating a patient with rapid cognitive decline. Many conditions other than prion disease, however, including numerous reversible or curable conditions, can present as an RPD. This chapter discusses some of the major etiologies for RPDs and offers an algorithm for diagnosis.
Address correspondence to Dr Michael D. Geschwind, University of California, San Francisco, Memory and Aging Center, Box 1207, San Francisco, CA 94143-1207, firstname.lastname@example.org.
Relationship Disclosure: Dr Geschwind serves on the board of directors for San Francisco Bay Area Physicians for Social Responsibility and serves as a consultant for Advance Medical, Best Doctors Inc, the Franciscan Physician Network, the Gerson Lehrman Group Inc, Lewis Brisbois Bisgaard & Smith LLP, MEDACorp, and Quest Diagnostics. Dr Geschwind receives personal compensation as a speaker for grand rounds lectures and receives research/grant support from Cure PSP, the Michael J. Homer Family Fund, the National Institute on Aging, Quest Diagnostics, and the Tau Consortium.
Unlabeled Use of Products/Investigational Use Disclosure: Dr Geschwind reports no disclosure.