Spinal Cord Disease - Overview Flashcards
what order does functional loss occur in
- proprioception
- general proprioceptive ataxia - motor
- ambulatory paraparesis
- non-ambulatory paraparesis
- non-ambulatory tetraparesis
- paraplegia - sensory
- superficial vs deep nociception
paresis (paretic) vs paralysis (plegia)
paresis (paretic): some motor function but decreased strength
- ex. paraparetic - hind limb weakness +/- ambulatory
paralysis (plegia): unable to walk and has no motor function
- ex. paraplegia - hind limbs completely paralyzed
what are the phases of acute spinal cord injury
biphasic
primary: contusion, laceration, compression, or traction (direct mechanical injury)
secondary: vascular, electrolyte, and biochemical changes, edema, loss of energy metabolism
what is the outcome of secondary acute spinal cord injury
necrosis and apoptosis
caused by lack of perfusion, hyper-saturation of Na/Ca, ischemia, etc
can lead to myelomalacia in cases of severe acute spinal cord injury
myelomalacia
spinal cord liquefaction from necrosis and apoptosis (secondary injury)
ascending/descending from the lesion itself
develops within 3-7 days
occurs in 10-20% of dogs with severe spinal cord injury (paraplegic w/ no pain perception)
signs of myelomalacia
- shift from UMN –> LMN signs
- flaccid abdomen
- loss of cutaneous trunci
- respiratory failure
localization of spinal cord lesions based on spinal reflexes
C1-C5: UMN signs in TL and PL
C6-T2: LMN signs in TL, UMN in PL
T3-L3: normal TL, UMN in PL
L4-Cd: normal TL, LMN in PL
T3-L3 myelopathy - classic presentation
normal thoracic limbs
UMN signs in pelvic limbs
- normal to exaggerated PLs
CS:
- paresis/plegia in PLs
- CP deficits in PLs
- proprioceptive ataxia in PLs
- +/- hyperesthesia
schiff-sherrington
acute, severe T3-L3 spinal cord injury leading to disruption of inhibitory interneurons to motor neuron of thoracic limb extensor muscles
thoracic limbs: rigid extension
pelvic limbs: paresis
spinal shock
immediate loss of spinal cord function caused by cessation of tonic input to spinal neurons from excitatory descending pathways
thoracic limbs: normal
pelvic: LMN signs (flaccidity)
temporary condition - resolved in hours/days
neurogenic shock
loss of sympathetic tone leading to decrease BP and HR from unopposed vagal tone
seen with severe traumatic injury
what is the most reliable prognostic indicator for spinal cord injury
presence of nociception
loss of deep pain = poor prognosis
- indicates IVD herniation
- 10-20% will develop myelomalacia
if loss of nociception caused by spinal fracture –> grave prognosis
what are the components of the vertebral column
bony + soft tissue (NP + AF)
cartilaginous endplates between each vertebrae
general DAMNITV scheme for spinal cord injury
D: IVDD
A: vertebral malformations
N: meningiomaa, PNST, lymphoma, histiocytic sarcoma, glioma
I: MUO/SRMA, infectious meningomyelitis, discospondylitis
T: vertebral fracture/luxation
V: fibrocartilaginous embolism, infarctions, ANNPE
how to narrow down differentials for spinal cord injury
- timeline: acute vs chronic
- progression: progressive vs non-progressive
- symmetry: symmetrical (anomalous, metabolic) vs asymmetrical (degen., neoplasia, inflammatory, vascular, trauma) signs
- +/- hyperesthesia
- neuroanatomic localization
