Characterising the uncommon corticobasal syndrome presentation of sporadic Creutzfeldt-Jakob disease

Background: Corticobasal syndrome (CBS), which encompasses cortical sensory loss, alien limb, bradykinesia, rigidity, limb apraxia and dystonia, is the classic presentation of corticobasal degeneration (CBD). It may occur in other neurodegenerative disorders including sporadic Creutzfeldt-Jakob disease (sCJD). Current CBD diagnostic criteria outline features of CBS but fail to distinguish CBD from other causative pathologies.

Objectives: To characterise the CBS presentation of sCJD (sCJD-CBS) in the context of existing CBD diagnostic criteria.

Method: Data of two new cases of sCJD-CBS and seven patients identified from the Australian National Creutzfeldt-Jakob Disease Registry database was reviewed. Additional data from 11 published cases was incorporated to illustrate the natural history of sCJD-CBS. Comparison was made with pathologically diagnosed CBD cases with ante-mortem CBS presentation (CBD-CBS).

Results: sCJD-CBS accounts for 1.8% of all Australian sCJD cases. Compared to CBD-CBS, disease progression is more rapid in sCJD-CBS (median time to diagnosis 48 vs.1.5 months, p < 0.001; and disease duration until death 68 vs. 5 months, p < 0.001). Although no clinical features separate the two, alien limb and myoclonus tend to occur early in sCJD-CBS following initial 'sensory' disturbance in the affected limb. Consistent with sCJD, distinctive diffusion weighted imaging (DWI) abnormalities on magnetic resonance imaging may also occur in sCJD-CBS.

Conclusion: sCJD should be suspected in patients presenting with CBS when clinical progression is rapid and accompanied by DWI abnormalities, even without cerebrospinal fluid 14-3-3 protein detection and electroencephalographic periodic sharp wave complexes. We propose the addition of rapid (<12 months) progression to akinetic-mutism or death and DWI abnormalities as exclusions in future CBD diagnostic criteria.