Sporadic lower motor neuron disease with a snake eyes appearance on the cervical anterior horns by MRI

Sasaki, Shoichi

doi:10.1016/j.clineuro.2015.06.006

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…In Case 4, which demonstrated rapidly progressive and asymmetric thoracic limb weakness and muscle atrophy from a central cord syndrome, no etiology for the SEM-like phenotype was identified. In humans, both adult-onset sporadic lower motor neuron disease (LMND) or Hirayama disease can have clinical, electrophysiologic, and SEM findings that overlap with those observed in Case 4 (21, 22). Although it is possible that the canine SEM-like phenotype with no identifiable etiology could be a manifestation of a sporadic variant of canine spinal muscular atrophy, the age of onset, clinical presentation and progression, MRI appearance, focal distribution and neuropathologic features of lesions we observed in Case 4 were not consistent with any currently described variant of canine LMND (23–25).…”

Section: Discussionmentioning

confidence: 99%

“…Although it is possible that the canine SEM-like phenotype with no identifiable etiology could be a manifestation of a sporadic variant of canine spinal muscular atrophy, the age of onset, clinical presentation and progression, MRI appearance, focal distribution and neuropathologic features of lesions we observed in Case 4 were not consistent with any currently described variant of canine LMND (23–25). In addition, unlike Case 4, human adult-onset sporadic LMND has a more favorable outcome with signs being very slowly progressive or even spontaneously abating in some patients (21). In Hirayama disease, forward displacement of the cervical dural sac and compressive flattening of the lower cervical cord occurs during neck flexion (22).…”

Section: Discussionmentioning

confidence: 99%

“…Numerous studies in humans have attempted to associate different types and severities of ISC, including SEM, with patient prognosis. Several investigations in humans have implicated that SEM is an irreversible change associated with a poor prognosis for neurological recovery (9, 13, 26), while others suggest that SEM may be reversible depending on the cause or in the presence of early therapeutic intervention (12, 21). To further elucidate the pathogenesis of the SEM-like phenotype, performance of dynamic or vascular cervical imaging examinations should be considered if this type of ISC is identified on static MR images.…”

Section: Discussionmentioning

confidence: 99%

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Canine Snake-Eye Myelopathy: Clinical, Magnetic Resonance Imaging, and Pathologic Findings in Four Cases

et al. 2019

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Intramedullary signal change (ISC) is a non-specific finding that is frequently observed on magnetic resonance imaging (MRI) examinations of the canine spinal cord. ISC can represent a variety of primary pathological processes such as neoplasms or myelitides or secondary changes such as edema, cysts, gliosis, or myelomalacia. An unusual phenotype of ISC is the “snake-eye” myelopathy (SEM), which refers to bilaterally symmetric T2 hyperintensities preferentially affecting the ventral horn gray matter on transverse MR images, which resemble a pair of snake's eyes. The pathophysiology of SEM is poorly understood in humans, and this imaging finding may be associated with cervical spondylotic myelopathy, spinal cord ischemia, ossification of the posterior longitudinal ligament, amyotrophic lateral sclerosis, and Hirayama disease. Here we describe four dogs with cervical MRI examinations consistent with an SEM-like phenotype. All dogs initially presented with a central cord syndrome or tetraparesis referable to a C6-T2 neuroanatomic localization, which was attributed to disc-associated spinal cord compression in three cases, while one dog had the SEM-like phenotype with no identifiable etiology. Once the SEM-like phenotype was present on MRI examinations, dogs demonstrated insidious clinical deterioration despite therapeutic interventions. Deterioration was characterized by lower motor neuron weakness and neurogenic muscle atrophy progressing to paralysis in the thoracic limbs, while neurological functions caudal to the level of the SEM-like lesion remained largely preserved for months to years thereafter. Neuropathological features of the SEM-like phenotype include multisegmental cavitations and poliomyelomalacia of laminae VI-IX of the caudal cervical spinal cord, although the lesion evolved into pan-necrosis of gray matter with extension into the adjacent white matter in one case with an 8 years history of progressive disease. Although the pathophysiology of SEM remains unknown, the topographical distribution and appearance of lesions is suggestive of a vascular disorder. As the SEM-like phenotype was uniformly characterized by longitudinally and circumferentially extensive neuronal necrosis, results of this small case series indicate that dogs with clinical signs of central cord syndrome and the SEM-like phenotype involving the cervicothoracic intumescence on MR examinations have a poor prognosis for the preservation or recovery of thoracic limb motor function.

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