Compression of Central Nervous System
- Compression may arise within or outside the spinal cord.
- Causes of compression include:
- Abscess
- Abscesses may be extradural, vertebral or intervertebral.
- Fracture of vertebral bodies
- Traumatic fracture
- Pathological fracture, due to abscess, metabolic causes or neoplasia.
- Neoplasia
- Intervertebral disk disease
- Prolapsed disks can cause acute or chronic compression.
- Malformations
- Wobbler horses
- Caused by stenotic myelopathy.
- The vertebral canal narrows due to malformation and malarticulation of the cervical vertebrae (usually C3-C4)
- Cervical vertebral malformation-malarticulation in dogs has a similar pathogenesis to wobbler horses
- Atlantoaxial subluxation of toy dogs.
- A hypoplastic dens leads to subluxation.
Pathology
- Lesions associated with focal compressive spinal cord injury are similar regardless of cause.
Gross
- The spinal cord may be indented or flattened.
Histological
- The myelin sheath may balloon in all funiculi.
- Axonal swelling and loss is seen.
- Macrophages appear within days and remove debris within myelin "digestion chambers".
- Neuronal loss, gliosis, malacia and oedema may also be apparent.