Myelopathies Flashcards
Degenerative disc disease
Most common spinal problem in dogs, relatively infrequent clinical disorders in cats.
Hansen type 1
— chondroid degeneration —> decrease water binding abilities and commonly undergoes calcification.
— primarily occurs in small breed dogs, particularly in chondrodystrophic breeds.
— rapid onset of clinical signs (minutes to days)
Hansen type 2
— progressive thickening of the dorsal annulus fibrosus.
— usually occurs in non chroncrodystrophic larger breed dog.
— slow onset of clinical signs (weeks, months to years).
Both types have been reported in cats.
Cervical spondylomyelopathy (Wobbler syndrome)
Common disease of the cervical vertebral column in large to giant breed dog
Characterized by a dynamic and static compression of the cervical spinal cord, nerve rood deficits and neck pain.
Disc associated : more common in doberman
Osseous form : more common in giant breed such as Great Dane. Tend to be younger at the time of presentation.
Clinical presentation : chronic progressive history (several weeks to months) is typical. Acute presentation is usually associated with neck pain. Cause proprioceptive ataxia affecting all 4 limbs.
Degenerative myelopathy
Cause : degenerative disease of unknown etiology
Presentation : primarily affecting the thoracolumbar spinal cord of medium to large breed dogs > 5yo. Most commonly affected breed includes GS and boxers. Slowly progressive non painful T3-L3 myelopathy in middle aged to large breed dogs. Loss or proprioceptive ability (ataxia, toed dragging) is noted initially, followed but a gradual loss of voluntary function. Spinal reflex are typically normal to hyperreflexive. Late in the disease progress, urinary or fecal incontinence may develop. The disease usually progress over 6-12 months.
Other differentials of degenerative myelopathy
- Extradural synovial cyst
- Rottweiler leukoencephalopathy
- Leukodystrophies
- Hereditary ataxia
- Labrador retriever axonopathy
- lysosomal storage disease.
Atlanto axial instability
Absence of intervertebral disk in the AA joint - supported only by ligaments.
Cause : malformation of the dens (hypoplasia or aphasia)
Presentation : miniature and toy dog breeds, often less than 2yo. Onset of clinical signs can be acute or chronic. Can vary from neck pain with no neurological deficits to tetraplesia with respiratory difficulty.
Other causes of developmental myelopathy
Vertébral malformation, spinal dwarphism, cartilaginous exostoses, meningo/myomeningoceles, spinal arachnoid cyst, stenotic vertebral canal.
Extradural tumors
Primary is more common than secondary
Primary
— Dog : Osteosarcoma is the most common
— Cats : Lymphosarcoma is the most common
Secondary :
— Dog : carcinoma
Intradural/extradura tumor
Meningioma and MNST
Intramedullary tumors
Infrequent
Nutritional causes of myelopathy
Hypovitaminose A and methionine deficiency.
Discospondylitis
Infection of the intervertebral disc and surrounding vertebral end plates that is usually caused by bacteria
Most common bacteria : Staphylococcys spp
Any vertebral level can be affected but L7-S1 space is one of the most common.
Myelitis and meningomyelitis
Clinically differentiated by the presence of pain
Clinical signs depend of the affected region and include paresis or paralysis, pain and proprioceptive deficits. Subacute and chronic presentation are seen.
Consistent feature is asymmetric deficits
Fibrocartilaginous embolie myelopathy
Common syndrome caused by embolisation or arterial and or venous supply to an area of the spinal cord.
This disease usually affects non-chondrodystrophic dogs, principally large to giant breed dogs. Also possible in smaller breeds and in cats.
history of peracute to acute onset and progression of clinical signs.
Most patients will reach peak severity of neurological dysfunctions within 24 hours.
Common spinal hyperesthesia.
Deficits are often moderate to strongly asymmetric and the clinical signs are typically not progressive after the first 24 hours.
