Pathogenetic role of myelitis for syringomyelia

Area of Science:

• Neuroscience
• Neurology
• Pathology

Background:

• Syringomyelia is typically linked to cerebrospinal fluid (CSF) flow obstruction.
• However, syringomyelia can occur without evident CSF obstruction, particularly with inflammatory spinal cord lesions (myelitis).
• Vasogenic edema and interstitial fluid accumulation are hypothesized as alternative mechanisms.

Observation:

• A prospective case series examined transient syringomyelia in patients with non-infectious myelitis (sarcoidosis, post-infectious, Devic's, MS).
• Syringes developed during acute myelitis, resolved with steroids, involved the central canal, and localized to the affected spinal segment.
• CSF flow obstruction was noted in only one patient; others lacked anatomical predispositions.

Findings:

• Syringomyelia associated with myelitis often lacks structural CSF flow block.
• Intrinsic medullary factors, including blood-spinal cord barrier breakdown and impaired fluid drainage, are implicated.
• Inflammation-triggered intramedullary processes are key drivers of syrinx formation.

Implications:

• This challenges the sole reliance on CSF obstruction models for syringomyelia.
• Highlights the importance of intrinsic spinal cord mechanisms in inflammatory conditions.
• Suggests new therapeutic targets focusing on spinal cord inflammation and edema management.