Letter to the editor concerning “hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature” by S. Ben Amor et al. (Eur Spine J. 2013, Jun 1)
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KeywordsSpinal Cord Transcranial Magnetic Stimulation Corticospinal Tract Motor Evoke Potential Spastic Paraparesis
To the Editor,
We read with great interest the article by Ben Amor et al.  published in the European Spine Journal entitled “Hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature”. The authors state in their paper that there is no special diagnostic tool for hepatic myelopathy (HM), and that the diagnosis has to be established on clinical grounds after exclusion of other possible entities. However, in our opinion, there is a noticeable omission in this important article. Our previous study  revealed that motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) may be very helpful in the diagnosis of this rare complication of chronic liver diseases that is usually associated with a portosystemic shunt and likely to be overlooked. The authors demonstrated that central motor conduction studies by means of TMS are sensitive, accurate and easily applicable methods for detecting even a subclinical damage of the corticospinal tract. The threshold for corticospinal electrophysiological abnormalities was below that for clinical and/or radiological changes. Spinal cord involvement was evident even at the preclinical stage and became more overt as the disease progressed. Most of the examined patients did not have clinical symptoms and presented only physiological subclinical abnormalities.
MEP studies may thus disclose an impairment of the corticospinal pathways even before HM is clinically manifest and enable an early diagnosis of HM. Since, liver transplantation (the first therapeutic option) should be performed before spinal cord damage becomes irreversible [3, 4, 5], the diagnosis of HM must be established as early as possible to enhance the chance of a complete recovery of the spinal cord. Therefore, we believe that such an important examination, which is at present widely and easily performed in the most neurophysiology laboratories, cannot be neglected. We found important to highlight that, especially in a review article on HM, this important diagnostic tool should be included and discussed.
Conflict of interest
- 1.Ben Amor S, Saied MZ, Harzallah MS, Benammou S (2013) Hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature. Eur Spine J [Epub ahead of print]Google Scholar