Principles of myelopathies in LA Flashcards
What are the 2 main types of osseous malformation/stenosis?
type 1: dynamic
type 2: absolute (constant compression)
What is dynamic stenosis/ CVM type 1?
when the neck is flexed or hyperextended, the vertebrae move excessively causing cord compression. commonly affects c3-c5 and most frequent in young animals
worse with flexion c3-c5 and extension c5-7
What is absolute stenosis/CVM type 2 (static)?
osseous changes in the vertebrae that cause spinal cord compression
usually affects older horses at c5-c7
osteoarthritic changes in the articular process joints as a result of congenital OCD
other malformed vertebrae
What are common abnormalities in the spine?
caudal extension of the dorsal vertebral lamina
caudal epiphyseal flare/ski ramo
step
What is the difference between intervertebral ratio radiographs in young vs older horses?
young: high sensitivity and specificity
old: much lower sensitivity and specificity
What is the tx in equine cervical vertebral malformation/stenosis?
pace diet (restricted growth of foal by limiting protein intake)
articular process joint medication
ventral stabilisation
What are the clinical signs of EHV1?
ascending paresis/ataxia
systemic signs: pyrexia, depression
bladder incontinence, tail paresis
urine scalding
occasionally cranial nerve signs
How is EHV1 transmitted?
inhalation
fomites
viral replication/shedding
within 24
sheds for 7-14 days
infection likely lifelong
What is the characteristic pathology of an EHV1 spinal cord?
haemorrhages secondary to vasculitis and thrombosis
secom=ndary to viral replication in endothelial cells and immune complex localisation in blood vessel walls
often symmetrical
What causes the extent of neurological deficit in EHV1 cases?
correlates to the extent of vascular compromise
What are the clinical signs of equine degenerative myeloencephalopathy EDM?
rare 6 months to 2 years
symmetric ataxia, weakness
hindlimbs more affected than forelimbs
hyporeflexia over trunk
What is the post-mortem pathology of the spinal cord in EDM?
neuronal fibre degeneration and demyelination in matter of ascending/descending tracts of spinal cord
mid thoracic region often worse affected
