Discussion

CJD belongs to a group of disorders referred to as transmissible spongiform encephalopathy. The clinical manifestations of CJD vary. Early-stage disease is characterized by behavioral change, deterioration in intellectual function and cerebellar dysfunction [9]. Approximately 90% of patients with CJD present with movement disorders; generalized myoclonus is common in advanced-stage disease [8]. However, other focal involuntary movements are rare, especially in early-stage disease. Dystonia as an early symptom of CJD is quite rare as well, but when present, it is usually unilateral with distal distribution. Several CJD cases presenting with focal dystonia have been reported [2, 3, 6]. In these reported cases, dystonia was associated with other movement disorders such as focal myoclonus, focal or generalized chorea, tremor and bradykinesia. Dystonia progressively evolved to hemidystonia or generalized dystonia with rapid deterioration in cognitive function in these patients. A few CJD cases with an atypical history of corticobasal degeneration, such as the alien hand phenomenon, apraxia and parkinsonism have also been reported [10–12]. Our patient presented with unilateral dystonia, which evolved to generalized dystonia during the course of the disease; in addition, there were superimposed myoclonic jerks with rapid deterioration in cognitive and motor function. Parkinsonism and other clinical features of corticobasal degeneration were not observed. In sporadic CJD, a bilateral symmetrical increased signal in the striatum on T2-weighted MR sequences is a distinctive finding; less commonly, asymmetrical involvement of the pallidum, thalamus and cerebral (especially occipital) cortex on T2 or proton density MR sequences is observed [13]. Some reports have shown typical MR findings of CJD [2, 6]. However, prior reports have not shown the corresponding lesion associated with focal dystonia or involuntary movement on MR images.