What are the key clinical features that differentiate Creutzfeldt-Jakob disease (CJD) from other neurodegenerative disorders?

Key clinical features that differentiate Creutzfeldt-Jakob disease (CJD) from other neurodegenerative disorders include a rapidly progressive dementia combined with prominent myoclonus, cerebellar signs, and visual disturbances, often accompanied by akinetic mutism in later stages. Unlike typical neurodegenerative diseases such as Alzheimer's or Parkinson's, CJD progresses over weeks to months rather than years, which is a critical distinguishing factor NICE NG97.

Early clinical presentation often includes rapidly evolving cognitive decline with marked attention and executive dysfunction, alongside characteristic involuntary muscle jerks (myoclonus) and ataxia. These features are less common or develop more slowly in other dementias NICE NG97.

Additional differentiating signs include cortical blindness or visual field defects and extrapyramidal symptoms, which may mimic Parkinsonism but with a much faster progression. The presence of periodic sharp wave complexes on EEG and characteristic MRI changes (such as hyperintensity in the basal ganglia or cortical ribboning) further support the diagnosis of CJD over other neurodegenerative conditions NICE NG97.

Recent literature highlights that CJD can present with atypical or unusual clinical features, sometimes mimicking other neurological disorders, which complicates early diagnosis. However, the rapidity of progression and combination of myoclonus with rapidly progressive dementia remain key clinical clues Mead & Rudge 2017Baiardi et al. 2018.