Spinal Cord Disorders Flashcards
LMN lesion
- focal weakness
- severe focal atrophy
- fasciculations may be present
- decreased muscle tone and dec MSR
UMN lesion
- diffuse weakness
- mild atrophy
- no fasciculations
- INC muscle tone (spasticity)
- INC MSR
- clonus
- pathological reflexes (Babinski sign)
C5,C6
deltoids, biceps
C7,C8
triceps
C8,T1
interossei, flexor digitorum (finger flexors)
L2,3,4
iliopsoas (hip flexor), quadriceps
L4,5
tibialis anterior (foot dorsiflexor)
S!,2
gastrocnemius (foot plantar flexor)
radicular (root) pain
lightening, stabbing, shooting electrical pain in the dermal distribution of a dorsal root
what does radicular (root) pain indicate?
-dorsal root inflammation which occurs in shingles from Herpes zoster
OR
-compression by an extramedullary lesion with arises outside the spinal cord
extramedullary vs intramedullary pain
- extra (herniated intervertebral disc or vertebral tumor) may also produce a more constant dull local pain
- intra arises inside sc, creates diffuse or no pain
what indicates intramedullary lesion within the spinal cord itself
a suspended pattern of deficit with sacral sparing (since sacral is at the very edge; order: c.t.l.s)
what indicates an extramedullary lesion arising from outside the spinal cord
a sensory deficit for pain and temp up to a level with sacral involvement
what would a severe fracture and displacement of the T12 vertebral body approximately affect
the L3 level of the spinal cord itself
transection of transverse myelopathy
complete (or nearly complete) lesion encompassing cross-sectional extent of the sc at one or a few adjacent levels
transverse myelitis
when lesion is inflammatory or infectious in nature
C8 transverse myelopathy
- severely atrophic, weak hand muscles with fasciculations
- spastic, hyper-reflexic, weak lower limbs with Babinski signs
- bladder and bowel dysfunction may occur from impairment of descending motor tracts which control the sacral anterior horn cells that innervate the sphincter muscles
what happens when the transection is due to severe, acute TRAUMA
- the setting of spinal or neurogenic shock may initially be present
- UMN aign emerge weeks or months later
involvement of what may impair phrenic nerve function and cause respiratory failure
extensive involvement of anterior horn cells at levels C3,C4,C5 (keeps the diaphragm alive)
What are some causes of transverse myelopathy
- tumors (especially vertebral mets)
- spinal stenosis (sc compression from degen of bony spinal column and herniated intervertebral discs)
- extradural hemorrhage or abscess
what causes transverse myelitis
- viral infections
- rxn to vaccines
- ai demyelination of the sc (eg from MS)
role of corticosteroids
rapidly help reduce sc edema from tumors or myelitis and improve recovery of those with severe sc trauma
Brown-Sequard syndrome (sc hemisection)
- contra deficit to pain and temp sensation
- ipsi deficit of vibe and position sense
- ipsi weakness
what are common causes of hemisection
- trauma
- extramedullary tumors
- herniated discs with regenerative disease of the bony spine
syringomyelia
- spinal cord lesions from a syrinx, or cavity, within or near the center of the sc
- an intramedullary lesion, primarily affects gray matter
where does a syrinx usually occur
in the cervical or thoracic spinal cord, may extend over several segments or levels in a longitudinal or r-c direction enlarging slowly over time
syringomyelia cp
- suspended sensory level with sacral sparing, shawl/cape
- preservation of the vibration and position sense
- may be a late residual of severe sc injury
causes of syringomyelia
- traumatic cervical sc hemorrhage will resorb if pt survives leaving a cavity/syrinx in its place
- intramedullary sc tumors
- impaired CSF flow (Chiari malformation)
anterior spinal artery
- supplied by several radicular branches of the aorta and has a midline longitudinal orientation
- supplies anterior/ventral 2/3 of the spinal cord (sc stroke would occur if it were blocked or occluded)
anterior spinal artery occlusion 1/2
- usually occurs in lower thoracic or upper lumbar spinal cord
- involvement of the corticospinal tracts there=paraplegia with UMN signs in lower limbs and a thoracic level of sensory loss, without sacral sparing, to pain and temp
- vibe and position sense are nml
anterior spinal artery occlusion 2/2
- back pain or radicular pain are common initial s/s
- occurs suddenly and progresses over hours (like a stroke)
posterolateral syndrome/subacute combined degeneration
- classically due to vit b12 deficiency
- in the sc demyelination and degeneration of the white matter takes place at thoracic levels
- vibe and position sense are reduced/lost in lower limbs
- spastic paresis from involvement of the corticospinal tract
- pain and temp are not affected
- may also be caused by copper deficiency or HIV
ALS
- diffuse motor neuron lesions: cerebral cortex, brain stem, spinal cord
- sensory pathways are not affected
- bowel and bladder function remain nml
- radicular pain is not present
- fasciculations are prominent
when would you suspect a cervical myelopathy
if LMN signs developed in the upper limbs and UMN signs were found in the lower limbs
tabes dorsalis
-neurosyphilis affecting the spinal cord
tabes dorsalis path
- lumbosacral dorsal roots become infected and inflamed producing severe radicular lightening pains in the lower limbs
- dorsal and posterior columns degenerate=impairment of vibe and position sense
- loss of sensation in lower limbs where reflexes are lost (afferent reflex arcs are disrupted)
- strength remains intact since motor neurons and corticospinal tract are spared
