385 Ch 384. Prion Disease and Rare Causes of Dementia

Prion diseases (TSEs) = transmissible spongiform encephalopathies caused by misfolded prion protein (PrP); human prion diseases: sporadic CJD (sCJD ~ 85%) + familial (genetic CJD, GSS, FFI ~ 15%) + acquired (variant CJD from BSE, iatrogenic, kuru rare)；sCJD presentation: rapid progressive dementia + myoclonus + ataxia + visual changes + behavioral changes — death within months；diagnosis: MRI DWI (cortical ribboning + basal ganglia bright) + EEG (PSWCs — periodic sharp wave complexes, late) + CSF (RT-QuIC most accurate >> 14-3-3 protein, total tau) + brain biopsy/autopsy gold standard；no treatment；other rare dementias: HIV-associated neurocognitive disorder (HAND) + neurosyphilis + Whipple disease + autoimmune encephalitis (anti-NMDA-R, anti-LGI1) + paraneoplastic + chronic infections + heavy metals + leukodystrophies + mitochondrial + neurometabolic。