Spinal Cord disorders Flashcards
what are LMN signs
focal weakness severe atrophy fasciculations decreased muscle tone decreased reflexes
What are UMN signs
diffuse, severe weakness mild atrophy increased muscle tone (spasticity) increased reflexes possible clonus posible babinski sign
when are LMN signs seen
when there is a spinal cord lesion affecting the anterior horn cells that innervate the muscles of the limb
when are UMN signs seen
in limbs below a spinal cord lesion that affects the corticospinal tract
•ipsilateral cervical or thoracic spinal cord lesion or
• contralateral brainstem or brain lesion
what is radicular (root) pain
lightning, stabbing or shooting electrical pain in the dermatomal distribution of a dorsal root.
what does radicular pain indicate
inflammation of the dorsal root
what are 2 examples that cause radicular pain
Herpes zoster
compression by an extramedullary lesion
what kind of pain does an extramedullary lesion itself cause (not the resulting compression)
constant dull, local pain
what kind of pain is caused by an intramedullary lesion
diffuse pain or none at all
how can radicular pain be relieved
analgesics, anti-inflammatory medications or nerve block procedures.
chronic root pain - anticonvulsants and antidepressants
what are the signs and symptoms of a spinal cord lesion in the spinothalamic tract
pain and temperature deficit in the contralateral body
dermatomal level of loss approximates the level of the lesion
what would a suspended patter of pain and temperature loss with sacral sparing indicate
intramedullary lesion
due to disruption of the decussating spinothalamic tract fibers and possibly medial portions of the STT
where are sacral fibers located in the STT
laterally
what would a sensory deficit for pain and temperature up to a level with sacral involvement indicate
extramedullary lesion (compressing from outside the spinal cord)
where would you expect position sense and vibration sense deficits due to a spinal cord lesion
ipsilateral side
lesion would affect the DCP (crosses in the medulla)
how would an extramedullary lesion present
radicular pain with sensory loss up to a level including sacral
how would an intramedullary lesion present
diffuse or no pain, sensory loss would be suspended with sacral sparing
what is a transverse myelopathy
complete lesion of the spinal cord
what is a transverse myelitis
a transverse myelopathy that is inflammatory in nature
what can be used to approximate the level of a transverse myelopathy (transection)
the dermatomal level of sensory loss and the presence of any lower motor neuron signs
what causes spinal or neurogenic shock
trauma
what is spinal or neurogenic shock
weakness my be accompanied by decreased muscle tone and muscle stretch reflexes with the expected UMN signs only gradually emerging weeks to months later
a lesion at what level could cause respiratory failure
involvement of anterior horn cells at C3, C4, C5 - may impair phrenic nerve function
what are some examples of extramedullary lesions that could cause transverse myelopathy
tumors, spinal stenosis, extradural hemorrhage or abscess, severe spinal cord ischemia
what are examples of inflammatory causes of a transverse myelopathy
viral infections, autoimmune demyelination (MS)
how does a Brown-Sequard lesion present?
- contralateral pain and temperature deficit
- ipsilateral deficit of vicration and position sense
- ipsilateral weakness with LMN and UMN signs
what are common causes of Brown-Sequard hemisection lesions
trauma, extramedullary tumors and herniated discs with degenerative disease of the bony spine
when would you see a Horner’s syndrome with a Brown-Sequard lesion
if it was above T1
what is a syringomyelia
spinal cord lesion from a syrix or cavity within or near the center of the spinal cord (primarily affects the grey matter there) - intermedullary lesion
what are the most common locations for a syrinx
the cervical or thoracic spinal cord and may extend over several segments or levels - enlarging slowly over time
what tracts/fibers are interrupted by a syrinx
selectively interupts the decussating fibers of the STT
what symptoms does syringomyelia cause
defitic of pain and temperature ofver the dermatomes involved but sparing of the sacral dermatomes = suspended sensory level with sacral sparing (cape-like pattern)
may expand causing weakness later on
preservation of vibration and position sense bc DCP is spared
what causes syringomyelia
later residual of severe spinal cord injury
i.e. a traumatic cervical spinal cord hemorrhage will resob if the patient survives leaving a cavity or cyrix in its place
other causes- intramedullary spinal cord tumors or impaired CSF flow from a congenital abnormality of the posterior fossa (Chiari malformation)
what is a congenital malformation that may cause a syringomyelia
Chiari malformation - abnormality in the posterior fossa that prevents the flow of CSF
what does the anterior spinal artery supply
the anterior 2/3 of the spinal cord
what happens if the anterior spinal artery is blocked
a “spinal cord stroke” occurs
what causes occulsion of the anterior spinal artery
atherosclerotic disease of the aorta, or a complication of surgery for an aortic aneurysm, or an aortic dissection in a hypertensive patient
what is the most common location of an anterior spinal artery occulsion
lower thoracic or upper lumbar spinal cord
what are the symptoms of an anterior spinal artery occulsion
paraplegia with UMN signs in the lower limbs and a thoracic level of sensory loss, without sacral sparing to pain and temperature.
vibration and position sense remain normal (posterior dorsal columns are preserved)
back or radicular pain are common initial symptoms. Symptoms occur suddenly and progress over hours
what causes posterolateral syndrome or combined degeneration
Vitamin B12 deficiency
rarely copper deficiency of HIV
is posterolateral syndrome or combined degeneration reversible
yes if caught early
what other problems may accompany posterolateral syndrome or combined degeneration
polyneuropathy, optic neuropathy and dementia - all can be caused by vit B12 deficiencies
what happens in posterolateral syndrome or combined degeneration and where does it take place
demyelination and degeneration of the white matter usually at thoracic levels
what does “combined degeneration” refer to
involvement of the posterior and lateral columns
what are the symptoms/signs of posterolateral syndrome or combined degeneration
vibration and position sense are reduced or lost in the lower limbs (unsteadiness and falling if the patient walks in the dark or with eyes closed)
spastic paraparesis from involvement of the corticospinal tract
pain and temperature are not affected
what is ALS
degenerative disease affecting UMN and LMN, lesions occur diffusely
What important features of ALS helps distinguish it from a spinal cord lesion
it does not affect the sensory pathways, bowel and bladder functions remain normal, and radicular pain is not present
what is tabes dorsalis
nervous system involvement by infection with syphilis
where is the lesion in tabes dorsalis
lesion of the dorsal roots and dorsal spinal cord
what are the symptoms of tabes dorsalis
first - severe radicular pains in the lower limbs
then impairment of vibration and position sense in the lower limbs, eventually all sensation in the lower limbs is lost, and loss of reflexes
strength remains in tact
