Rapidly progressive young-onset dementias: neuropsychiatric aspects.

Rapidly progressive dementia (RPD) is roughly defined as neurocognitive decline resulting in dementia or death within 2 years. Although RPDs affect all age groups, many occur in patients with young-onset dementia. Although prion disease (eg, Creutzfeldt-Jakob disease) is often thought to be the prototypic rapidly progressive young-onset dementia, the differential diagnosis is broad and some etiologies may be treatable. Hence, an appropriate workup to determine the etiology of RPD is crucial to planning the appropriate management. This article reviews the differential diagnosis, diagnostic workup, and management considerations for this unique patient population.