|LETTER TO THE EDITOR
|Year : 2015 | Volume
| Issue : 6 | Page : 840-841
Pulvinar/hockey stick sign in Creutzfeldt - Jakob disease
Eswaradass Prasanna Venkatesan, Kalidoss Ramadoss
Department of Neurology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India
|Date of Web Publication||19-Nov-2015|
Eswaradass Prasanna Venkatesan
Department of Neurology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Venkatesan EP, Ramadoss K. Pulvinar/hockey stick sign in Creutzfeldt - Jakob disease. Med J DY Patil Univ 2015;8:840-1
Here, we describe a 58-year-old female came with a history of insidious onset of memory decline, difficulty in identifying close relatives, and unsteadiness of gait progressing rapidly over 3 months. On examination, patient was conscious but had poor attention, and detailed lobar functions could not be done. Her Mini Mental State Examination was only seven. On examination, she had ataxic gait, the stimulus sensitive myoclonus with no pyramidal or extra pyramidal signs. Since the patient had myoclonus and rapidly progressing dementia Creutzfeldt - Jakob disease (CJD) was suspected. Electroencephalography done showed bilateral diffuse slowing. Cerebrospinal fluid analysis for 14-3-3 could not be done due to financial constraints. Diagnosis of CJD was made with the help of magnetic resonance imaging (MRI).
Creutzfeldt - Jakob disease is a rare transmissible spongiform encephalopathy caused by proteinecious infectious particle called PrP (prion).  A number of CJD subtypes are recognized. The most common is sporadic CJD (sCJD), which is found worldwide and has an incidence of about one per million annually. In 1996, a new clinicopathologically distinct form was described and named variant CJD (vCJD) and most patients have been residents of the United Kingdom.  MRI is indispensable in making diagnosis and ruling out other conditions. Bilateral symmetrical abnormal high signal intensity in the posterior thalamus is the pulvinar sign and in dorsomedial thalamic nuclei and pulvinar is the "hockey-stick" sign [Figure 1]a and b]. 
|Figure 1a: Magnetic resonance imaging diffusion-weighted images shows diffusion restriction in bilateral medial thalami, basal ganglia and cortical ribbon sign.|
Figure 1b: Magnetic resonance imaging diffusion-weighted images shows diffusion restriction in bilateral medial thalami (hockey-stick sign), basal ganglia and cortical ribbon sign
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Characteristic findings in sCJD on MRI are best seen on diffusion-weighted images (DWI) and to a lesser extent on fluid-attenuated inversion recovery (FLAIR) images and are 91% sensitive and 95% specific for the diagnosis of sCJD. These findings include hyperintense signals within the cortical ribbon, basal ganglia, and thalamus. In sCJD, cortical ribboning is the most common MRI finding, followed by basal ganglia hyperintensities.
Magnetic resonance imaging features of vCJD were medial thalamic and periaqueductal grey-matter high signal, and the notable absence of cerebral atrophy. Present indications are that FLAIR sequences are most likely to show the abnormality. The pulvinar sign was originally defined simply as the hyperintensity of the pulvinar. In young patients, the normal basal ganglia are relatively hyperintense compared to old and rarely in sCJD patients can have pulvinar sign, and this could be mistaken for vCJD. Hence, the pulvinar sign is redefined as the hyperintensity of the pulvinar relative to the signal intensity of the anterior putamen. 
Here we describe a case of sCJD with pulvinar/hockey-stick sign mimicking vCJD. Hyperintensity of all deep gray-matter nuclei, with the pulvinar less bright than the anterior putamen and caudate, is a feature of sCJD, which is useful to differentiate it from vCJD. Our patient had a similar picture. In addition to pulvinar sign, lack of cerebral atrophy and younger onset favours vCJD. Further studies are needed to assess the radiologic-neuropathologic correlates in vCJD and sCJD. In the appropriate clinical context, the MRI identification of pulvinar sign is a useful noninvasive test for the diagnosis of vCJD and can avoid tonsillar biopsy. But it can rarely occur in sCJD like in our case, and it should not be misdiagnosed as vCJD.
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