Poliomyelitis-like syndrome

Last revised by Frank Gaillard on 11 Jun 2022

Poliomyelitis-like syndrome, or polio-like paralysis, is an uncommon form of myelitis that presents similar to polio, due to non-poliovirus pathologies which selectively involve the anterior horn cells of the spinal cord and result in an anterior horn syndrome. Although it usually has an infective etiology, there are rare non-infective etiologies too.

Patients with poliomyelitis-like syndrome present with selective neurological deficits due to anterior horn involvement; acute flaccid paralysis and areflexia of the involved limb without sensory impairment 1-7

There are many causes:

MRI of the spine is the modality of choice for assessing for signal abnormality of the anterior horn cells

MRI typically reveals involvement of the ipsilateral anterior horn cells. If there is radioculomyelitis, there may be thickening of the ventral nerve roots of the cauda equina.

  • T2: hyperintense anterior horn cells 1-5
    • on axial imaging, this has the characteristic owl's eyes sign, which appears as thin anterior 'pencil-like' linear T2 hyperintensities 5
  • T1 C+ (Gd): generally no enhancement unless there is radicular involvement 1,3

Depending on the underlying etiology, there may also be imaging findings related to concurrent encephalitis.

The differential diagnosis is largely that of other causes of anterior horn syndrome or owl's eyes sign and includes: 

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