To illustrate an atypical case of slowly progressive Creutzfeldt-Jacob disease (CJD) in a patient with prior diagnosis of Lewy Body Dementia (LBD), neurocognitive and psychiatric symptoms for 2 years, and positive RT-Quic

CJD is often described as a rapidly progressive and fatal neurodegenerative disorder caused by misfolded proteins (prions) in the brain. Clinically, patients with CJD present with rapid onset dementia and multifocal neurologic findings such as startle myoclonus. This condition can progress to akinetic mutism, somnolence, and death usually within 1 year of disease onset. We describe a patient with prior diagnosis of LBD and neurocognitive decline for 2 years who was ultimately found to have positive RT-Quic suggestive of prion disease. This case highlights the phenotypic variability of the disease and suggests that certain forms of this condition may have a more slowly progressive presentation than previously described.

Case report and literature review.

A 64-year-old man with prior diagnosis of LBD presented for acute on chronic decline in cognition, behavior, and self-care. His family described a 2-year history of paranoia, possible visual hallucinations, decline in short-and-long term memory, and impaired executive dysfunction with difficulty in organization and completing activities of daily living, such as paying the bills. On exam, the patient had delusionary thoughts, impaired cognition, and increased tone. MRI brain showed global cortical atrophy and cortical ribboning. CSF testing revealed mild protein elevation of 68 mg/dL and positive 14-3-3 protein. RT-Quic returned positive. He was diagnosed with probable atypical form of CJD.

CJD is often considered a rapidly progressive dementia. We report a patient with positive RT-Quic and slowly progressive neurocognitive decline for 2 years characterized mostly by cognitive and behavioral changes. As atypical, more slowly progressive and variant forms of CJD exist, the diagnosis of prion disease should be considered in patients with dementia.