Neuro 17.2: Spinal Cord Lesions Flashcards
What is the mutation in Friedreich Ataxia?
unstable trinucleotide repeat (GAA) in the frataxin gene
What is Friedreich Ataxia?
- a degenerative disorder of the cerebellum and spinal cord tracts
- *** “Friedreich is Fratastic (frataxin): he’s your favorite frat brother, always staggering and falling but has a sweet, big heart.”
Where does sensory info for pain/temperature ascend?
in the spinothalamic tract
Why does dysfunction of the frataxin gene cause Friedreich Ataxia to occur?
- normal = essential for mitochondrial iron regulation
- damage = increased risk of free radicals via the Fenton reaction –> free radical damage of neurons
What is Riluzole? What is it for? How does it work?
- tx for ALS/Lou Gehrig disease
- decreases glutamate excitotoxicity (via unknown mech.)
- *** “For Lou Gehrig disease, give rilouzole”
Dx?
- unstable trinucleotide repeat (GAA) in the frataxin gene
Friedreich Ataxia
Where in the spinal cord is the the hypothalamic spinal tract found?
in the lateral horns
What does syringomyelia arise in assoc. with?
- trauma
- Arnold-Chiari malformation
Who classically gets Amyotrophic Lateral Sclerosis (ALS)?
middle-aged adults
Where does sensory info for pain/temperature decussate?
at the anterior white commissure
This is the name for the cystic degeneration of the spinal cord at the anterior white commissure.
syringomyelia
Dx?
- a degenerative disorder of upper AND lower motor neurons (the corticospinal tract)
Amyotrophic Lateral Sclerosis (ALS)
How is polio transmitted?
fecal oral
Which spinal cord lesion presents with a “cape-like” distribution of symptoms?
syringomyelia
O2- + superoxide dismutase = _______
H2O2
What does a negative Babinkski sign look like?
downgoing toes
What are the initial s/s of a poliovirus infection?
- fever
- sore throat
- ab pain
- nausea/vomiting
How can Amyotrophic Lateral Sclerosis (ALS) be distinguished from syringomyelia?
there is NO sensory impairment in Amyotrophic Lateral Sclerosis (ALS)
At what level of the spinal cord does syringomyelia classically occur?
C8-T1
If a syringomyelia lesion expanded, it would knock out the anterior horns and then the ______ of the spinal cord.
lateral horns
On which chromosome is the frataxin gene located?
chromosome 9
What are the 3 classic findings of Horners syndrome?
ptosis, myosis, and anhydrosis
Where does sensory info for pain/temperature synapse?
in the posterior horn of the spinal cord
What is the prognosis for Werdnig-Hoffman disease?
death w/i a few years after birth (median = 7 mos)
What disease presents like poliovirus?
Werdnig-Hoffman disease
What is Amyotrophic Lateral Sclerosis (ALS)?
a degenerative disorder of upper AND lower motor neurons (the corticospinal tract)
Where in the body does poliovirus initially infect?
oropharynx and small bowel
Dx?
- a degenerative disorder of the cerebellum and spinal cord tracts
- ataxia
- loss of vibration sense
- loss of proprioception
- muscle weakness in lower extremities
- loss of DTRs
Friedreich Ataxia
How does poliomyelitis present?
- lower motor neuron signs:
- muscle weakness and atrophy
- decreased tone
- impaired reflexes
- flaccid paralysis
- negative Babinksi sign (downgoing toes)
What info. does the dorsal column of the spinal cord carry?
fine touch/position sense
If a syringomyelia lesion expanded, it would first knock out the _____ of the spinal cord.
anterior horns
What runs thru the lateral horn of the spinal cord?
the hypothalamal spinal tract- sympathetic input to the face
Upper motor neurons start in the cortex and first synapse in the anterior horn of the spinal cord. Then, the lower motor neuron continues on to the _______.
muscle
What are the upper motor neuron (UMN) dysfunction signs?
- spastic paralysis
- hyperreflexia
- increased muscle tone
- positive Babinski sign (= upward going toes)
How is Werdnig-Hoffman disease transmitted?
auto. recessive inheritance
What are the clinical s/s associated with loss of the hypothalamal spinal tract at T1?
- ptosis, myosis, and anhydrosis (Horner’s syndrome)
What are the sensory findings in syringomyelia?
- loss of pain and temp. sensation in the upper extremities
- ***fine touch, position sense in tact
How does one get Friedreich Ataxia?
it’s auto. recessive
What is poliomyelitis?
damage to the anterior motor horn due to poliovirus infection
Upper or lower motor neuron defect?
- muscle weakness and atrophy
- decreased tone
- impaired reflexes
- flaccid paralysis
- negative Babinksi sign
lower motor neuron
What will the CSF findings be in polio?
- increased WBCs
- slightly increased protein
- normal glucose
What is the function of the frataxin gene?
it’s essential for mitochondrial iron regulation
O2- –> H2O2 via?
superoxide dismutase (SOD)
What are the signs of lower motor neuron dysfunction?
- muscle weakness and atrophy
- decreased tone
- impaired reflexes
- flaccid paralysis
- negative Babinksi sign = downgoing toes
Where does sensory info for pain/temperature synapse in the brain?
the thalamus –> cortex
Does polio present with symmetric or asymmetric weakness? What about Werdnig-Hoffmann disease?
- polio = asymmetric
- Werdnig-Hoffmann = symmetric
What familial mutation is known to cause Amyotrophic Lateral Sclerosis (ALS)?
zinc-copper superoxide dismutase mutation
In the hypothalamic spinal tract, a nerve arising in the ______ synapses on the lateral horn at T1.
hypothalamus
In the hypothalamic spinal tract, a nerve arising in the hypothalamus synapses on the _______ at T1.
lateral horn
Do ALS pts have bowel/bladder deficits?
nope
Where is the cell body located for pain/temperature?
in the sensory ganglion outside the spinal cord
How many different nerves are used to transmit pain/temperature info from the periphery to the brain?
3
This gene is essential for mitochondrial iron regulation.
the frataxin gene
How is Amyotrophic Lateral Sclerosis (ALS) transmitted?
- most = sporadic genetic mutations
- some = familial zinc-copper superoxide dismutase mutation
What other pathology is Friedreich Ataxia associated with?
- hypertrophic cardiomyopathy
- diabetes mellitus
- hammer toes
Upper motor neurons start in the cortex and first synapse in the _______.
anterior horn of the spinal cord
Ataxia + multiple spinal cord tract dysfunction = ?
Friedreich Ataxia
What is the function of superoxide dismutase (SOD)?
removal of free radicals
How does poliovirus get to the CNS?
hematogenous spread
What occurs in the posterior horn of the spinal cord?
pain/temperature sensory info synapses here
What info. is transmitted in the anterior horn of the spinal cord?
motor neurons
Dx?
- an inherited degeneration of the anterior motor horn
Werdnig-Hoffman disease
Why is syringomyelia?
a cystic degeneration of the spinal cord at the anterior white commissure
In the hypothalamal spinal tract, a nerve arising in the hypothalamus synapses on the lateral horn at _____.
T1
Is there loss of pain/temp sensation in ALS or syringomyelia?
syringomyelia
Where in the spinal cord does syringomyelia classically occur?
in the anterior white commissure
How does Werdnig-Hoffman disease present?
- a floppy baby
- tongue fasciculations
- s/s similar to polio but will have SYMMETRIC WEAKNESS
Upper or Lower Motor Neuron dysfunction signs?
- spastic paralysis
- hyperretlexia
- increased muscle tone
- positive Babinski sign
Upper motor neuron
Dx?
- damage to the anterior motor horn due to poliovirus infection
- lower motor neuron signs
poliomyelitis
What is the result if the anterior white commissure of the spinal cord is lesioned?
bilateral loss of pain and temperature sensation
What neuro. disease is hypertrophic cardiomyopathy assoc. with?
Friedreich Ataxia
When does Friedreich Ataxia present? How?
- in early childhood
- kyphoscoliosis
What info does the hypothalamic spinal tract carry?
sympathetic input to the face
How does Friedreich Ataxia present?
- ataxia
- loss of vibration sense
- loss of proprioception
- muscle weakness in lower extremities
- loss of DTRs
Does a syringomyelia usually affect the upper or lower limbs? Why?
- upper
- because they usu. occur at C8-T1
What is an early sign of Amyotrophic Lateral Sclerosis (ALS)?
- atrophy
- hand weakness
What occurs in the at the anterior white commissure of the spinal cord?
sensory info for pain/temperature decussates
What does a zinc-copper superoxide dismutase mutation cause?
Amyotrophic Lateral Sclerosis (ALS)
Does Amyotrophic Lateral Sclerosis (ALS) present with upper or lower motor neuron dysfunction signs? Why?
- Both
- Anterior motor horn involvement = LMN signs
- Lateral corticospinal tract involvement = UMN signs
What is the tx for ALS? How does it work?
- riluzole
- decreases glutamate excitotoxicity (via unclear mech.)
- *** “For Lou Gehrig disease, give rilouzole”