Syringomyelia

From Dog
Syringomyelia visible on MRI imaging of a Cavalier King Charles Spaniel[1]

Syringomyelia is a rare neurological disease of dogs characterized by cavity or cyst formation within the spinal cord or brain.

This disease may occur as a primary congenital disoder, such as is observed in Cavalier King Charles Spaniels, or as a secondary disease such as chiari malformations[2].

Congenital syringomyelia (cavitation of the spinal cord parenchyma) and hydromyelia (dilatation of the central canal within the spinal cord) are relatively uncommon malformations of the spinal cord that result from incomplete closure or development of the neural tube[3].

This disease may occur in isolation or together (hydrosyringomyelia) and may be localized to a short segment of the spinal cord or along great distances.

Syringomyelia has been reported in association with:

Dynamic changes in cervical spinal cord intramedullary pressure with the neck in the flexed position have been postulated to play an important role in syrinx growth[7].

Hydrosyringomyelia may also occur secondary to edema of neoplasms, spinal cord trauma, vascular compromise, or inflammation[8]. Cervical hydrosyringomyelia with communication to the 4th ventricle has been observed in a dog with a nerve sheath tumor involving a C6 nerve root[9].

Syringomyelia is considered to result from a rupture of the ependymal lining of a dilated central canal with dissection of adjacent spinal cord parenchyma or is the result of edema collecting in the dorsal funiculi secondary to the hydromyelia.

Affected animals of various breeds (not including the Weimaraner breed with myelodysplasia) range in age from 12 weeks to 12 years.

Clinical signs include hemiparesis, scoliosis, torticollis or cervical pain[10][11]. Other signs persistent intense scratching at the shoulder or flank region, muscle atrophy of cervical epaxial muscles and/or thoracic limb muscles, weakness, especially in thoracic limbs, and decreased spinal reflexes[12].

Diagnosis is based on clinical signs and supportive CT or MRI analysis of the spinal column.

Blood tests and CSF analysis are usually unrewarding.

Myelography may revealed diffuse spinal cord enlargement and presence of contrast agent within the central canal (canalogram)[13].

Successful medical, e.g., long-term prednisolone and furosemide or surgical treatment, including syringotomy and drainage have been reported.

References

  1. Baywood Pets
  2. Rusbridge C, MacSweeny JE, Davies JV, et al (2000) Syringohydromyelia in Cavalier King Charles spaniels. J Am Anim Hosp Assoc 36:34-41
  3. Bailey CS. (1975) An embryological approach to the clinical significance of congenital vertebral and spinal cord abnormalities. J Am Anim Hosp Assoc 11:1975
  4. Malik R et al (1991) Abnormal control of urination and defaecation in a dog with myelodysplasia. Aus Vet Pract 21:178-180
  5. Bagley RS, Harrington ML, Tucker RL, et al (1996) Occipital dysplasia and associated cranial spinal cord abnormalities in two dogs. Vet Radiol Ultrasound 37:359-362
  6. Kirberger RM, Jacobson LS, Davies JV, et al (1997) Hydromyelia in the dog. Vet Radiol Ultrasound 38:30-38
  7. Tachibana S, Kitahara Y, Iida H, et al (1994) Spinal cord intramedullary pressure. A possible factor in syrinx growth. Spine 19:2174-2178
  8. Rossier AB, Foo D, Shillito J, et al (1985) Posttraumatic cervical syringomyelia. Incidence, clinical presentation, electrophysiological studies, syrinx protein and results of conservative and operative treatment. Brain 108:439-461
  9. Levitski RE, Lipsitz D, Chauvet AE. (1999) Magnetic resonance imaging of the cervical spine in 27 dogs. Vet Radiol Ultrasound 40:332-341
  10. Smith BA. (1995) Hydrosyringomyelia, hydrocephalus and scoliosis in a Rhodesian Ridgeback dog. Aus Vet Pract 25:79-86
  11. Levitski RE, Lipsitz D, Chauvet AE. (1999) Magnetic resonance imaging of the cervical spine in 27 dogs. Vet Radiol Ultrasound 40:332-341
  12. Rusbridge C. (1997) Persistent scratching in Cavalier King Charles spaniels. Vet Rec 141:179
  13. Johnson L, Rolsma M, Parker A. (1992) Syringomyelia, hydromyelia and hydrocephalus in two dogs. Prog Vet Neurol 3:82-86