Corticospinal involvement in patients with a portosystemic shunt due to liver cirrhosis

Abstract

Hepatic myelopathy (HM) is a rare complication of chronic liver diseases usually associated with a portosystemic shunt, causing a progressive spastic paraparesis, and is likely to be overlooked. Thirteen patients with liver cirrhosis associated with surgical or spontaneous portosystemic shunts were studied to determine the frequency and gravity of HM. Six patients exhibited clear-cut signs of spinal cord involvement and four of them exhibited varying degrees of disability. Neurological examination did not reveal any abnormalities in the other patients. Motor evoked potentials (MEPs) were measured in all patients; in five of them the examinations were done before and after orthotopic liver transplantation (OLT). The patients with clinical signs of spinal cord involvement exhibited severe neurophysiological abnormalities, whereas milder but unequivocal MEP abnormalities were found in four of the seven patients with normal clinical examination. The clinical and neurophysiological features of patients with slight MEP abnormalities improved after OLT, whereas the patients with a more advanced stage of disease (severe MEPs abnormalities) did not. Our findings indicate that MEP studies may disclose an impairment of the corticospinal pathways even before HM is clinically manifest and provide evidence that early diagnosis of HM and subsequent immediate liver transplantation have to be recommended.

Answer to the letter to the editor of R. Nardone et al. concerning “Hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature” (by Sana Ben Amor et al. (2013), Eur Spine J; DOI 10.1007/s00586-013-2828-z)

“…R. Nardone et al for their comments. We are in agreement that the motor evoked potentials (MEP) elicited by transcranial magnetic stimulation may be helpful in the diagnosis of hepatic myelopathy especially in patients with chronic liver disease associated with a portosystemic shunt [1]. But we think that MEP is not specific for this pathology.…”

“…On the other hand, MEP could be abnormal in cirrhotic patients before hepatic encephalopathy is clinically manifesting [4]. This complication is more frequent than hepatic myelopathy in patients with chronic liver disease [1].…”

Central motor and sensory conduction in patients with hepatic myelopathy

“…21 In contrast, Nardone et al 5 found an abnormal CMCT to the lower lumbar spinal segments and a normal CMCT to the upper cervical spinal segments, thus supporting localization of main dysfunction to the thoracic spinal cord. Moreover, another MEP study of HM patients indicated that the sites of higher vulnerability are located between the upper thoracic and the lumbar spinal cord.…”

“…In particular, nitrogenous products such as ammonia have been identified as a major contributor to the development of HM. 17 Interestingly, Nardone et al 5 found that clinical and MEP results of patients with a more advanced stage of disease (with markedly prolonged CMCT) were not substantially altered by liver transplantation, whereas patients with strong evidence of early-stage disease (minor CMCT abnormalities) exhibited clear neurophysiological and clinical improvement after liver transplantation. These MEP findings suggest that HM may be reversible if treated in the early stages of the disease, 18,19 whereas spinal cord dysfunction remains unchanged or is less likely to be reversed by liver transplantation in the later stages.…”

“…[1][2][3][4] Motor evoked potentials (MEPs) studies disclosed MEP abnormalities even in patients with normal clinical examination. 5 However, sensory function has poorly been explored in HM patients.…”