Section 7 - Spinal Cord Flashcards

1
Q

What is amyotrophic lateral sclerosis?

A

Lou Gehrig Disease. Abnormal reflexes (upper and lower motor neuron involvement). No sensory loss; progressive loss of all motor neurons. Particularly severe when muscles of respiration are affected.

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2
Q

What is myasthenia gravis?

A

Autoimmune abnormality where antibodies bind to the nicotinic acetylcholine receptors at neuromusclar jxn, blocking normal effects of acetylcholine to depolarize muscle and elicit response.

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3
Q

List symptoms of myasthenia gravis.

A
  • Muscle weakness/compromise of ability to elicit skeletal muscle response - this waxes and wanes over time
  • Diplopia, ptosis (both seen first; eye mm. affected first)
  • Dysarthria (difficult/unclear speech)
  • Dysphagia
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4
Q

What is syringomyelia?

A

Cavitation of central region of spinal cord. NOT the central canal.

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5
Q

A small syrinx damages:

A

Fibers crossing anterior white commissure (ALS); damage ALS tract destined bilaterally to specific spinal levels. (2 levels below, bilaterally).

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6
Q

A large syrinx damages:

A

Anterior white commissure AND anterior horn –> bilateral sensory loss at specific levels, weakness of extremity

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7
Q

What is a hydrosyringomyelia?

A

A cavitation of the central canal.

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8
Q

Non-communicating syringomyelia ______.

Communicating syringomyelia ______.

A
  • Is separate from the central canal.

- Has a cystic structure connecting to the central canal.

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9
Q

What is Brown-Sequard Syndrome?

A

A hemisection of the spinal cord that reflects damage to lateral corticospinal tract, ALS, and dorsal columns.

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10
Q

List symptoms of Brown-Sequard Syndrome.

A
  • Muscle weakness/paralysis ipsilaterally
  • Loss of pain and thermal sensation contralaterally
  • Loss of proprioception, vibratory, fine touch ipsilaterally
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11
Q

What is a radiculopathy?

A

Damage to nerve root, typical of disk/spine disease and impingement syndromes. Sharp, localized pain related to dermatome. (Single root might not cause big sensory loss, due to overlap of dermatomes).

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12
Q

What is a mononeuropathy?

A

Damage to defined peripheral nerve, often from trauma or entrapment (like carpal tunnel). Leads to paresthesia, pain, weakness in target tissue.

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13
Q

List some characteristic examples of a mononeuropathy.

A
  • Tongue deviation (XII)
  • Flexion/adduction, extension of fingers (ulnar)
  • Foot dorsiflexion (fibular)
  • Forearm pronation (median)
  • Flexion of toes (tibial)
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14
Q

What is a polyneuropathy?

A

Damage in multiple peripheral nerves, so both motor and sensory.

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15
Q

What is glove and stocking sensory loss?

A

Lesions/neuropathy starts in lower extremity then begins in upper; moves from periphery to central locations (involving small diameter fibers first). Diabetes mellitus causes this.
- Lose sensation of temp/pain, then vibration/proprioception, weakness of extremities/hyporeflexia

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16
Q

What is a motor neuropathy, and what does it lead to?

A
  • Loss of anterior horn motor neurons

- Flaccid weakness, muscle fasciculations, muscle atrophy

17
Q

What is a sensory neuropathy, and what does it lead to?

A
  • Loss of cell bodies in DRG

- Distal and proximal extremity affected

18
Q

What is a lower-motor lesion?

A
  • Skeletal mm. activity affected (the final common pathway)

- FLACCID paralysis, muscle ATROPHY, diminished or ABSENT deep tendon reflexes

19
Q

What is an upper-motor lesion?

A
  • Damage to cerebral hemispheres or lateral white columns of spinal cord
  • SPASTIC paralysis, NO atrophy, HYPERACTIVE deep tendon reflex, Babinski’s sign
  • Often caused by stroke, tumor, infection
20
Q

What results from occlusion/spasm of anterior spinal artery (Central Cervical Cord Syndrome)?

A
  • Bilateral weakness of extremities (mostly upper)
  • Patchy loss of sensation below lesion
  • Urinary retention
21
Q

What is poliomyelitis?

A

Viral infection leading to spinal cord inflammation of gray matter

22
Q

What are symptoms of poliomyelitis?

A
  • Headaches
  • Red/sore throat
  • Slight fever
  • Vomiting
  • Abnormal reflexes
  • Back/neck stiffness
23
Q

What is tabes dorsalis?

A

Slow degeneration of sensory neurons in dorsal columns of spinal cord. Occurs as secondary demyelination due to untreated syphilis.

24
Q

What are symptoms of tabes dorsalis?

A
  • Weakness
  • Diminished reflexes
  • Paresthesias
  • Hypoesthesias
  • Progressive locomotor ataxia
25
Q

What is spinal shock?

A

Loss of sensation accompanied by motor paralysis with gradual recovery of caudal reflexes following a spinal cord injury

26
Q

What is deafferentiation pain?

A

Nerve rootlets/tracts/nerves damaged/disrupted (lesions, damage to posterior rootlets, amputation). Results in:

  • Dull, aching, searing, pins-and-needles, burning sensations
  • Pain distributed to appropriate dermatome/region
27
Q

How do we treat deafferentiation pain?

A

DREZ (dorsal root entry zone) procedure - radiofrequency lesions made at levels of avulsed or lesion roots

28
Q

What are possible consequences of DREZ?

A
  • Can damage corticospinal tract and/or cuneate tract
  • Weakness of extremity on same side
  • No proprioception, vibration on ipsilateral side (buzzing)
29
Q

What is neuropathic pain?

A

Results from damage/disease affecting somatosensory system, continuous or episodic - pain is produced by non-painful stimuli (allodynia) and associated with abnormal sensations (dysesthesia).

30
Q

Describe Acute Central Cervical Spinal Cord Syndrome (or Central cord syndrome).

A

Incomplete spinal cord injury from traumatic hyperextension of cervical spine or mechanical injury –> bilateral damage to cervical spinal cord (anterior spinal artery)

31
Q

Signs of central cord syndrome?

A
  • Bilateral weakness of extremities (upper)
  • Patchy loss of sensation (pain, thermal) below lesion
  • Urinary retention
    Recovery is 4-6 days in reverse order of spinal cord location (bottom, up)
32
Q

What is the deep tendon reflex?

A

Stimulus of stretch (from a muscle spindle) typically elicited by tapping the large tendon - exerts rapid contraction of a muscle to resist the stretching (monosynaptic stretch reflex)

33
Q

What is the inverse myotatic reflex?

A

Autogenic/reciprocal inhibition - One group of muscles is excited and the antagonistic group is inhibited

34
Q

What is the Golgi tendon organ?

A

Responsible for autogenic inhibition; requires greater strength of stimulus (a higher muscle tension) for action than the muscle stretch (myotatic) reflex

35
Q

What is the flexor reflex?

A

Initiated by cutaneous input (nociceptive stimuli); responds to attempt to protect the body

36
Q

What is the crossed extension reflex?

A

Builds on circuit of flexor reflex; involves contralateral musculature to keep from falling (step on glass, lift up foot and stand on one leg)

37
Q

The gracile fasciculus carries SOME pain fibers. This could explain _______.

A

why some patients have recurrent pain after anterolateral cordotomy for intractable pain.

38
Q

Disruption of GVE fibers from the IML via a lesion of hypothalamospinal fibers in upper levels of cervical cord and medulla will produce ________

A

ipsilateral ptosis, miosis, anhidrosis, enophthalmos (Horner syndrome)

39
Q

Why can a high cervical cord lesion be deadly?

A

Phrenic nucleus is C3-7 in central region of anterior horn - preservation of breathing can become an issue