This term applies to a condition with many etiologies. Syringomyelia is characteristic of linear fluid collections within the spinal cord but outside the central canal. Hydromyelia applies to conditions where the enlarged collection is within the central canal.
Syringohydromyelia can be classified in several different ways such as traumatic vs. non-traumatic. The latter associated with Chiari malformations, neoplasms, arteriovenous malformations (AVM), arachnoiditis or spinal dysraphism. There is also an idiopathic (of unknown cause) form.
MRI is the investigation of choice when dealing with syringohydromyelia. Treatment is based on the etiology of the syrinx (the cyst within the spinal cord) and whether it is clinically significant and/or progressive. There is no medical therapy and neurosurgical consultation is appropriate.