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|Year : 2016 | Volume
| Issue : 5 | Page : 1088-1089
Early diagnosis of Varicella-zoster virus sciatic neuropathy by MRI neurography
Eugenia Rota1, Nicola Morelli1, Elena Belloni2, Paola Scagnelli2
1 Department of Neurology, Guglielmo da Saliceto Hospital, Piacenza, Italy
2 Department of Radiology, Castel San Giovanni Hospital, Castel San Giovanni, Italy
|Date of Web Publication||12-Sep-2016|
Department of Neurology, Guglielmo da Saliceto Hospital, Piacenza
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Rota E, Morelli N, Belloni E, Scagnelli P. Early diagnosis of Varicella-zoster virus sciatic neuropathy by MRI neurography. Neurol India 2016;64:1088-9
A 76-year-old woman presented with acute-onset right foot drop. Upon medical examination, leg weakness and sensory deficit were detected in the entire right sciatic nerve territory. The patient had complained of a tender and vesicular skin eruption prior to the onset of leg weakness, leading to the diagnosis of Varicella-zoster virus infection, which was confirmed by serology.
Five days after the clinical onset of the disease, the electroneuromyography (ENMG) was unremarkable, except for a reduced recruitment pattern in the muscles clinically affected by weakness.
The magetic resonance imaging (MRI) neurography is an emerging technique in the diagnostic algorithm of peripheral nerve damage that can be broadly divided into anatomic (high-resolution two-dimensional and three-dimensional spin echo-type imaging: conventional T2-based) and functional (diffusion-based) techniques.
The MRI revealed enlargement of the right sciatic nerve, with edema, and abnormal contrast enhancement [Figure 1],[Figure 2],[Figure 3], which may be attributable to impaired axonal transport. The patient was administered acyclovir intravenously for 10 days, during which time the clinical picture remained steady.
|Figure 1: Coronal T1-weighted image showing the two sciatic nerves. This Turbo-Spin-Echo acquisition allowed us to delineate the appearance and the course of the sciatic nerve in the coronal plane precisely. We can observe that the right sciatic nerve is enlarged (latero-lateral diameter: 0.77 cm), compared to the contralateral nerve (latero-lateral diameter: 0.37 cm)|
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|Figure 2: Coronal T2-weighted image with fat tissue saturation (STIR), showing that the right sciatic nerve (see arrows) is enlarged and hyperintense, suggesting the presence of edema. The STIR sequence is characterized by excellent suppression of tissues with low water content and enhancement of tissues with high water content (associated with edema)|
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|Figure 3: Gadolinium-enhanced axial T1-weighted image with fat tissue saturation, showing that the right sciatic nerve is characterized by abnormally high contrast medium uptake (see arrows). This Gradient-Echo acquisition allowed us to evaluate the hyperintensity of the nerve on a hypointense background accurately, with fast acquisition times|
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Four weeks after the onset of the symptomatology, the ENMG showed axonal damage and active denervation in the territory of the right sciatic nerve, which was more evident than that seen in the territory of the deep peroneal nerve.
MRI neurography is an promising imaging tool for the assessment of peripheral nerve damage; its value, compared to clinical and neurophysiological diagnostic methods, deserves further evaluation.
Our data suggest that MRI neurography may provide an early diagnosis of axonal neuropathy in its acute stage before electroneuromyography alterations become evident. It also provides a reliable anatomic-pathological localization, which has a good correlation with ENMG results. Hence, we suggest that the two methods be used as complementary tools in different stages of the diagnostic work-up of peripheral neuropathies.
The authors thank Mrs. Barbara Wade for her linguistic advice.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest
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[Figure 1], [Figure 2], [Figure 3]