Neurology -- Correspondence for Goh et al., 71 (5) 351-356

Correspondence published:

Presyrinx in children with Chiari malformations: Sabrina Ravaglia, Arrigo Moglia, Enver I. Bogdanov (Kazan State Medical University, Kazan, Russia) (29 August 2008)

Presyrinx in children with Chiari malformations 29 August 2008

Sabrina Ravaglia,
Institute of Neurology "C. Mondino"
via Mondino 2, 27100 Pavia, Italy,
Arrigo Moglia, Enver I. Bogdanov (Kazan State Medical University, Kazan, Russia)
Send Correspondence to journal:
Re: Presyrinx in children with Chiari malformations

sabrina.ravaglia{at}mondino.it Sabrina Ravaglia, et al.

Goh et al. report that only two out of six children with presyrinx and Chiari malformation had symptoms related to myelopathy. [1]
Although classically considered a neurosurgical condition, neurologists should also be aware of presyrinx and consider its possible paucisymptomatic picture and co-existence with a number of spinal cord medical disorders. Goh et al. also alluded to, but did not report the clinical detail of, five additional cases with an alleged presyrinx associated with spinal cord inflammation or tumors.
We previously reported a patient with a MRI-documented presyrinx associated with myelitis. [2] The suspect of a presyrinx was prompted by the following clues: a Chiari type I malformation; mild clinical symptoms of myelopathy in spite of MRI findings showing extensive longitudinal spinal cord edema; and, later, development of spinal cord cavitation. This cavitation disappeared with steroid treatment and surgical intervention was unnecessary. Steroid-induced reversion of the syrinx excluded the presence of a myelomalacic cavitation and suggested a pathogenic role for inflammation.
Our experience suggests that spinal cord inflammatory injury may trigger an otherwise silent structural abnormality, leading to the development of a presyrinx. This confirms the hypothesis that presyrinx derives from intra-parenchymal accumulation of extracellular fluid. [1] During inflammation, impairment of the blood-spinal cord barrier can lead to accumulation of protein-rich, osmotically active fluid that can further drive water into the interstitial compartment. Venous congestion can block fluid re-absorption preciptating a cycle that leads to expansion of the extracellular edema. In addition, changes in aquaporins expression induced by spinal cord disease of various etiologies, including inflammation, have recently been proposed to play a role in the development of presyrinx in an experimental model. [3]
We think that presyrinx should be considered in the differential diagnosis of myelopathy, not only in association with major structural malformations, but also with milder abnormalities. For instance, small posterior fossa, Chiari type 0 malformation, small spinal canal or foramen magnum can become relevant in association with a myelopathic condition that impairs the blood-spinal cord barrier. On the other hand, the presyrinx-associated edema can dramatically worsen the MRI findings of a myelitis, thus leading to the false impression of a much more extensive lesion.
Evaluation of aquaporin expression, kine-phase contrast MRI, and simultaneous measurement of mechanical, oncotic and osmotic pressures in the spinal cord cavity and subarachnoid space can help elucidate the pathophysiology of the edema formation in both inflammation- and compression-associated syringomyelia.
References
1. Goh S, Bottrell CL, Aiken AH, Dillon WP, Wu YW. Presyrinx in children with Chiari malformations. Neurology. 2008 Jun 18.
2. Ravaglia S, Bogdanov EI, Pichiecchio A, Bergamaschi R, Moglia A, Mikhaylov IM. Pathogenetic role of myelitis for syringomyelia. Clin Neurol Neurosurg. 2007;109:541-546.
3. Nesic O, Lee J, Ye Z, et al. Acute and chronic changes in aquaporin 4 expression after spinal cord injury. Neuroscience 2006;143:779-792.
Disclosures: The authors report no disclosures.
Editor�s Note: The authors of the article were offered the opportunity to respond but declined.