Spinal cord lesion and cranial nerves Flashcards
Temporary suppression of all reflex activity below the level of injury describes what?
Spinal shock
When does spinal shock occur?
Immediately after injury
The return of what reflex indicates the end of spinal shock?
Bulbocavernosus reflex
What are the clinical effects of spinal shock?
Flaccid paralysis Areflexia Loss of sensation - nociception and proprioception Loss of bladder and bowel reflexes
What are the phases of spinal shock?
Areflexia Initial reflex return Initial hyperreflexia Hyperreflexia and spasticity
How is the motor function of someone with a spinal cord injury assessed?
ASIA charts
How is sensory function after a spinal cord injury assessed?
Pin prick Light touch Sacral sparing
Who are the people involved in caring for someone with a spinal injury?
Spinal injury unit Physiotherapist Occupational therapist Family
What is the role of the physiotherapist in spinal cord injury rehabilitation?
Teaches wheelchair skills, helps relearn balance, strengthens paralysed muscles and teaching to transfer skills
What is the role of the occupational therapist in spinal cord injury rehabilitation?
Helps patients reach high level of physical and psychological independence at home and work Help with wheelchairs, computer aids and other tools
What is the role of the family in spinal cord injury rehabilitation?
Helps with income support, modifying homes, facilitates community nursing care
In which of an upper motor neuron lesion or a lower motor neuron lesion, is there muscle wasting?
Lower
In which of an upper motor neuron lesion or a lower motor neuron lesion, is there fasciculations?
Lower = twitching, motor units contract asynchronously because of abnormal repetitive discharge set up in the nerves
Describe the tone in both an upper motor neuron lesion and a lower motor neuron lesion
Lower motor neurons lesions lead to flaccid tone Upper motor neurons lesions lead to spastic tone
Describe the weakness/paralysis seen in both an upper motor neuron lesion or a lower motor neuron lesion
Lower - loss of muscle bulk Upper - ineffective recruitment of alpha motor neurons
Describe tendon jerk reflexes in both upper and lower motor neuron lesions
Lower - reduced or absent Upper - hyperreflexia
What happens to respiration if C3, 4 or 5 are damaged?
Phrenic nerve damage - innervates diaphragm Patient will need artificial ventilation to survive
What happens to respiration is C6 or C7 are damaged?
These nerves innervate the intercostal muscle- paradoxical breathing Phrenic nerve remains intact
What happens to respiration if T1 or below are damaged?
No effect
How much movement can be achieved if there is a spinal injury at C4?
None below the neck - quadriplegia
How much movement can be achieved if there is a spinal injury at C5?
There will be some control of the should and biceps No wrist or hand control
How much movement can be achieved if there is a spinal injury at C7-T1?
Most upper limb control May have dexterity problems with their hands and fingers
How much movement can be achieved if there is a spinal injury at T1-T8?
There will be paraplegia - full use of arms Poor control of the trunk as the abdominal muscles are effected Balance - still quite good
How much movement can be achieved if there is a spinal injury in the lumbar of sacral regions?
Decreased control of hip flexors and legs
Do patients often lose their micturition reflex?
No - the micturition reflex remains intact or recovers unless direct damage to micturition centre S2-4
What is the ‘autonomic bladder’
Sensory bombardment of the cord from stretch receptors - bladder emptying occurs when threshold is reached
How can micturition be indirectly controlled?
Patient increases sensory bombardment of sacral region by scratching the inner thigh, facilitating the reflex
Do somatic reflexes return after spinal injury?
Despite the fact that voluntary control of muscle never returns- somatic reflex do
Which reflexes return first?
Ankle Knee Hip- in sequence
Extensor reflexes return around 6 months after transection- what is different about them?
Exaggerated - leading to spastic paralysis
Describe autonomic dysrreflexia.
Stage of reflex activity that follows primary flaccidity of the shock Due to massive sympathetic discharge Trivial stimulus to body below the level of injury can trigger it
Signs and symptoms of autonomic dysrreflexia
Sweating Increased heart rate Hypertension Defecation Erection Micturition
What happens to blood pressure when the bladder fills in people with a spinal cord injury?
It increases - flushed face seen on urination
Does autonomic dysrreflexia resolve?
Primitive control of autonomic function is re-established - BP control remains more unstable than in normal people
What happens to the Babinski response reflex after spinal cord injury?
It initially disappears - and when it comes back, it occurs only in the abnormal form (positive response)
Which reflexes permanently disappear in a spinal cord injury?
Abdominal reflexes Cremasteric reflexes
In development, what do the alar and basal plates of the spinal cord become in humans?
Alar - dorsal horn Basal - ventral horn
What are the diagnostic reasons you would perform a lumbar puncture?
Withdrawal CSF Measure CSF pressure
What are the therapeutic reasons you would perform a lumbar puncture?
Administration of antibiotics Chemotherapy
Where would you perform a lumbar puncture?
Between L3 and L4 or between L4 and L5
What is the surface marker for the body of L4?
Supracristal line passes through the body of L4
In which part (superficial or deep) of the dorsal horn do the spinothalamic and dorsal column tracts terminate?
- Spinothalamic - superficial
- Dorsal column - deep
Which descending tracts are involved in muscle movement?
Corticospinal and corticobulbar
What descending tracts are involved with muscle tone maintainance?
- Reticulospinal
- Tectospinal
- Vestibulospinal
What commonly causes central cord syndrome?
Hyperextension injuries
Compression of the cord anteriorly by osteophytes and posteriorly by ligamentum flavum
Describe what brown-sequard syndrome is, and what commonly causes it.
Hemi-section of the cord
- stab wounds
- gunshot wounds
What does brown-sequard syndrome appear as clinically?
- Paralysis on affected side (corticospinal)
- Loss of proprioception and fine discrimination (dorsal column) on affected side
- Loss of pain and temperature loss on the opposite side (spinothalamic)
What causes cauda equina syndrome?
Due to bony compression or disk protrusion in the lumbar or sacral regions
What clinical symptoms arise from cauda equina syndrome?
- Back pain
- Bowel and bladder dysfunction
- Leg numbness/weakness
- Saddles paraesthesia
What is neurogenic shock?
The body’s response to the sudden loss of sympathic control - occurs in people who have a T6 injury or above - occurs in those who have a greater than 50% loss of sympathetic innervation
What is the clinical triad for neurogenic shock?
- Hypotension
- Bradycardia
- Hypothermia
What is the desired BP to assure good perfusion of the injured spinal cord?
85 mmHG MAP
What are people with a spinal cord injury high risk for, and require prophylaxis for?
- DVT
- Pulmonary embolism
What are the causes of spinal cord injury?
- Trauma - contusion or penetration/transection of neural tissue
- Compression - tumour haematoma or bony encroachment
Name the mechanism of spinal cord injury
- Hyperflexion
- Hyperextension
- Compression
What are the secondary effects of spinal cord injury
- Oedema
- Inflammatory/immune processes
- Ischaemia
What is neurogenic shock
Form of disruptive shock caused by the loss of brainstem and higher centre control of the sympathetic nervous system
What are the consequences of neurogenic shock?
Loss of sympathetic outflow:
- hypotension caused by peripheral vasodilation
- bradycardia
- reduced venous return
- loss of impulses from the thermoregulatory centre in the brain
- no sweating
What is the Babinsky response in lower motor lesion and upper motor lesion?
Lower - negative = normal toe flexion
Upper - Positive = abnormal toe extension
At what level is bladder control lost?
S2-4 and above - micturition centre If below S4-5 then some control left
Why do patients may find it hard to empty their bladder?
Loss of sympathetic control via hypogastric nerve - T12 - L1 - this nerve acts on beta3 receptors and keeps the detrusor muscle constricted
What is the timing of the 1st phase (areflexia and flaccidity) following spinal cord injury?
0 - 1 day
What is the underlying physiology of phase 1 (areflexia and flaccidity) following a spinal cord injury?
Loss of descending facilitation -> neurones involved in various reflex arcs lose the basal level of excitatory stimulation they normally receive from the brain
What is the timing of the 2nd phase (Initial reflex return) following spinal cord injury?
1 - 3 days
What is the underlying physiology of phase 2 (Initial reflex return) following a spinal cord injury?
Denervation supersentivity –> reflexes return due to the hypersensitivity of reflex muscle following denervation as more receptors for neurotransmitters are expressed, easier to stimulate - restoration of reflexes from polysynaptic to monosynaptic
What is the timing of the 3rd phase (Initial hyperreflexia) following spinal cord injury?
1 - 4 weeks
What is the underlying physiology of phase 3 (Initial hyperreflexia) following a spinal cord injury?
Axon-supported synapse growth - internerones and lower motor neurons below the transection begin sprouting, attempting to re-establish synapses - 1st synapses to form are shorter axons
What is the timing of the 4th phase (Hyperreflexia and spasticity) following spinal cord injury?
1 - 12 months
What is the underlying physiology of phase 4 (Hyperreflexia and spasticity) following a spinal cord injury?
Soma-suported synapse growth - takes longer since synapse formation is some-mediated
List all the cranial nerves
I Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Vestibulocochlear
IX - Glossopharyngela
X - Vagus
XI - Spinal accessory
XII - Hypoglossal
What is the periaqueductal grey?
- The primary control center for descending pain modulation
- Contains enkephalin-producing cells that suppress pain, located around the aqueduct
What is the red nucleus?
Structure in the rostral midbrain next to the substantia nigra involved in motor coordination
What are the cerebral peduncles?
Structures at the front of the midbrain which arise from the front of the pons and contain large ascending and descending nerve tracts that run to and from the cerebrum and the pons
What is the monosynaptic circuit for the knee jerk reflex?
2 neuorne reflex arc with a single central synapse
Describe the chain of events when a jerk reflex is elicited
1 - stimulus - tendon tap stretches the muscle 2 - activates muscle spindle 3 - conduction along afferent sensory fibres 4 - transmission at synapses between ia afferent and motor neurone 5 - conduction along efferent motor fibre 6 - neuromuscular transmission 7 - excitation contraction coupling 8 - twitch contraction of skeletal muscle
Where is the synapse of the monosynaptic reflex circuit?
In the ventral horn
What is the Jendrassik’s maneuver?
Reinforcing the reflex by recruiting more motorneurons and thus reaching the threshold for the reflex
What is the role of stretch reflex normally?
Prolonged stretch produces prolonged contraction - stretch reflex acts to maintain a constant muscle length and control muscle tone
What is the impact of sensory homunculus on the discrimination of touch?
Greater representation of some body parts - high degree of sensitivity and spatial discrimination in highly represented body parts e.g. hands and face
What are receptive fields and what creates them?
Each receptor formed by a peripheral endings of sensory receptor branch forms a receptive field
How do you test the receptive fields?
2-point discrimination test - at what distance can you recognize that it is 2 points touching not just one - to activate separate receptors it must fall within separate fields
What is the segmental root level of Jaw-jerk reflex?
Trigeminal nerve
What is the segmental root level of biceps reflex?
C5/6
What is the segmental root level of supinator/brachioradialis reflex?
C6/7 - radial nerve
What is the segmental root level of triceps reflex?
C6/7
What is the segmental root level of knee jerk reflex?
L2/3/4
What is the segmental root level of ankle jerk?
S1
What is the vestibulo-ocular reflex?
A gaze stabilizing reflex: the sensory signals encoding head movements are transformed into motor commands that generate compensatory eye movements in the opposite direction of the head movement, thus ensuring stable vision.
Label
What is the structure called and what nerves pass through?
Label
Label
Label
A - optic chiasm
B - optic tract
C - Pituitary stalk
D - Cerebral peduncle
E - Pons
F - Pyramids
G - Pyramidal decussation
What 2 main types of spinal cord injury can occur?
Complete
Incomplete
List the type of incomplete spinal cord injuries
Central cord syndrome
Anterior cord syndrome
Posterior cord syndrome
Brown - Sequard syndrome
Cauda equina syndrome
What part of spinal cord is affected in central cord syndrom and what is the group at increased risk?
Central area of the spinal cord
Elderly are more susceptible
What are the secondary sensory problems arising from spinal cord injury?
Asensate skin resulting in:
- Pressure soars
- Recumbency - The condition of leaning or reclining
- Death
What are the secondary bladder problems arising from spinal cord injury?
Intermittent - feeling pain and pressure in the area, can also be a catheter that is put in and removed
Management techniques:
- Indwelling catheter - stays in for long periods
- Suprapubic - inserted through abdominal wall
- Lofric catheter
- Silver coated
- Antibiotic
- Bladder stimulators
What are the secondary problems with bowel following spinal cord injury?
Diet
Lactulose
Senna - laxative
Manual evacuation
Bowel regime
What are the secondary problems with pain following spinal cord injury?
Acute vs chronic
Degenerative disease
Neuropathic pain
What are the secondary problems with sexual function following spinal cord injury?
Recreational and reproduction:
- Viagra and Cialis
- Stimulation
- Electro-ejaculation
Female
- Assisted conception
- Pregnancy - may not feel contractions or would not be able to push
- Can achieve vaginal birth
