Red flags: clinical features that might indicate a CJD mimic
| Feature | Indicates |
| Fever | Infections, lymphoma |
| Seizures | Implies less likely to be CJD, infective and immune encephalitis, neoplasia, many other mimics |
| Hyponatraemia | VGKC encephalitis |
| Facial movement disorder | NMDA-R encephalitis, CNS Whipple’s disease |
| Modest progression | Implies less likely to be CJD, more likely to be a common neurodegenerative disorder |
| CSF pleocytosis | Infections, lymphoma, inflammatory, neoplastic |
| Contrast-enhancing lesions | Infections, lymphoma, inflammatory, neoplastic |
| MRI hyperintensities on T2-weighted imaging outside the striatum, thalamus and cortex | Vascular diseases, lymphoma, progressive multifocal leukoencephalopathy, encephalitis, extrapontine myelinolysis, others |
CJD, Creutzfeldt–Jakob disease; CNS, central nervous system; CSF, cerebrospinal fluid; NMDA-R, N-methyl-D-aspartate; VGKC, voltage-gated potassium channel.