Week 4 in depth (Walsh)

Spinal cord and pathway pathology

What are the signs and symptoms associated with an UMN spinal cord injury

• hyperactive reflexes

• spasticity or hypertonicity

• positive babinski sign

• little or no muscle atrophy

What are causes of an UMN lesion?

• injury to brain

• injury to brainstem

• injury to spinal cord or white matter

What are causes of LMN lesions?

• injury to axons leaving spinal cord

• injury to ventral gray matter of spinal cord

• muscle disorders

• NMJ disorders: myasthenia gravis

What are the signs and symptoms of a LMN spinal cord injury

• hypoactive or absent reflexes

• flaccidity or hypotonicity

• negative babinksi sign

  • no signal arriving from neuron

• muscle atrophy

What should you look for clinically when assessing UMN damage?

immediately after loss of:

• somatic reflexes: stretch reflex, withdraw reflex

• autonomic reflexes: bowel/bladder

• regulation of BP: hypotension, control of sweating

several weeks after:

• some recovery of cord function

• return of reflexes below lesion

• hyperreflexive

What is the difference between a segmental tract lesion vs. a vertical tract lesion?

segmental

• interferes with neural function ONLY at the level of lesion

vertical tract

• loss of function below level of lesion

What are signs of a segmental tract lesion?

• abnormal or lost sensation in a dermatomal pattern

• motor neural signs in myotomal distribution

What are the signs of a vertical tract lesion?

• ascending: problems regulating BP, sweating, bladder and bowel control issues

• descending: paraylsis, spasticity, muscle hypertonia, babinski sign (if lateral corticospinal tract affected)

How would a peripheral region lesion present?

• sensation loss/alteration in peripheral nerve pattern

• decreased or loss of muscle power in peripheral nerve pattern

• NO vertical tract signs

• decreased or lost phasic stretch

How would a spinal region lesion present?

• sensation and muscle power loss in a dermatome and myotome distribution

• vertical tract signs

What are methods of injuring the spinal cord?

1. congential

2. direct trauma: MVA, falls, laceration

3. ischemia

4. pressure: disc herniation, stenosis, spondylosis

5. tumor: MCAA; LBP with coughing or sneezing

6. infection: osteomyelitis

7. demyelination: MS, GB syndrome

What are the ways SCI can be classified?

1. by neurologic level of injury

   1. most caudal level with normal sensory/motor function bilaterally

2. complete vs. incomplete

   1. complete: lack of sensory and motor function in lowest sacral segment

   2. incomplete: preservation of sensory and motor function in the lowest sacral segment

Explain the different spinal cord syndromes

What is the cause and effect of the following spinal cord syndromes: central cord, anterior cord, brown-sequard

central

• cause: hyperextension injury like diving into shallow water

• small: loss of pain/temp at level of lesion

• large: UE motor function impairment

anterior

• cause: hyperflexion injury like in wrestling

brown-sequard

• cause: bullet, knives, lateral hyperflexion

• half of spinal cord damaged

  • loss of movement on same side

  • loss of pain, temp, sensation on opposite side

What is Autonomic dysreflexia?

• MEDICAL EMERGENCY

• overreaction due to response to noxious stimuli

• affects SCI above T6

• signs

  • elevated BP

  • pallor below lesion

  • sweating and flushing around lesion

  • reduced HR

What are red flags associated with spinal cord?

• spinal cord lesion

• cauda equina syndrome

• intermittent claudication

  • pain in LE while walking that disappears with rest

Explain the different pathways to the spinal cord

What are some SCI-related diagnoses?

What are the 3 medial motor tracts and what are their functions?

1. reticulospinal

   1. bilateral postural muscles and gross limb movement

2. medial vestibulospinal and lateral vestibulospinal

   1. medial: positioning of neck

   2. lateral: postural muscles

   3. both: receive info about head movement/position from vestibular apparatus

3. medial corticospinal

   1. muscles of neck, shoulder, trunk

What are the two lateral motor tracts?

• rubrospinal

  • UE distal extensor muscles

• lateral corticospinal

  • activate inhibitory neurons to allow muscles to be independent

  • most important for controlling voluntary movements

What are the two nonspecific motor tracts?

• cerulospinal

• raphespinal

• activated during intense emotions

• can cause poorer motor performance when anxiety is high

What is the function of the corticobrainstem tracts?

• voluntary control of muscles in head and neck

• face, tongue, pharynx, larynx, trapezius, SCM

What are signs of a motor tract lesion?

• paresis and paralysis

• abnormal reflexes

• myoplasticity

• abnormal muscle tone

• loss of fractionated movements

• abnormal co-contraction

• abnormal muscle synergies

What are the effects of spinal motor tract lesions?

• paresis or paralysis results in limiting functional activities

• loss of phasic stretch reflex

• loss of withdrawal reflex

• contracture

• hyperreflexia

What are the levels of SCI according to the ASIA (ABCDE)

A: complete: no sensory or motor function preserved in S4-5

B: sensory incomplete: sensory preserved below neuroglogic level including sacral segment AND no motor function preserved

C: motor incomplete: motor function preserved at sacral segment

D: motor incomplete: same as above but half of muscles below lesion have MM >/= to 3

E: normal