Transcript Common Neurologic Drugs

Spinal Cord
Injury
Joselito B. Diaz, MD, FPNA
College of Rehabilitation Sciences
Spinal cord
• Continuation of the medulla
• Commences at the foramen
magnum and extends to the
level between L1 and L2
vertebrae
• 31 segments
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8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Relationship of spinal cord
segments to vertebral numbers
Vertebrae
Spinal segment
Cervical vertebrae
Add 1
Upper thoracic vertebrae
Add 2
Lower thoracic vertebrae (7-9) Add 3
Tenth thoracic vertebra
L1 and 2 cord segments
Eleventh thoracic vertebra
L3 and 4 cord segments
Twelfth thoracic vertebra
L5 cord segment
First lumbar vertebra
Sacral and coccygeal
cord segments
Spinal cord
• Posterior roots convey
sensory inputs while the
anterior roots conduct
efferent axons to the
innervate skeletal muscles
• Arterial blood supply comes
from the anterior spinal and
2 posterior spinal arteries
• Anterior spinal artery
supplies all the cord except
the dorsal horn and
posterior column
Sectional Organization of
the Spinal Cord
Spinal cord
(descending tracts)
• Lateral and anterior corticospinal
tract – convey axons from the motor
cortex
• Vestibulospinal tract – convey axons
from the lateral vestibular nucleus;
facilitate activity of extensor muscles
• Reticulospinal tract – transmit
autonomic axons and respiratory
motor fibers; facilitate or inhibit
voluntary movement
• Rubrospinal tract – facilitate activity
of flexor muscles
• Tectospinal tract – arise in the
superior colliculus, serves as
efferent pathway for spinal-visual
reflexes
Motor
pathway
Spinal effector Mechanism
Spinal cord
(ascending tracts)
• Lateral spinothalamic tract –
carry pain and temperature
sensation
• Anterior spinothalamic tract –
pathways for crude touch and
pressure
• Posterior columns – consists of
two tracts which convey
position, discriminative touch
and vibration sense
– Fasciculus gracilis and cuneatus
• Spinocerebellar tract – convey
propioceptive sensation to the
cerebellum
Somesthetic
System
Dorsal column
C
T
Spinothalamic tract
C
T
L
S
L
S
Corticospinal tract
C T
L
S
SCI Classification
• Tetraplegia – results from injury in the cervical
spinal cord
• Paraplegia – results from injury in the thoracic,
lumbar or sacral segments
• The neurological level is the most caudal spinal
segment that retains normal motor and sensory
function on both sides of the body
• The rectal area is examined digitally
– A complete lesion is defined as the absence of
sensory or motor function in the lower sacral
segment
– Incomplete lesion if either sensory or motor function
is present and known as sacral sparing
• ASIA defines the Zone of Partial
Preservation as up to 3 segments caudal
to the level of a complete injury, in which
impaired sensory or motor function is
found
• If any function is found more than 3
segments below the level, the lesion is
incomplete
Mechanisms of Injury
1. TRAUMA TO THE SPINE AND SPINAL CORD
• 10-14% of spinal fractures and dislocations result in
SCI
• Fracture-dislocation, pure fracture and pure dislocation
(3:1:1)
• Direct blow to the spine is a relatively uncommon cause
of serious spinal cord injury except for bullets, sharpnel
and stab wounds
• Mechanisms:
– Vertical compression of the spinal column to which
anteroflexion is added
• The adjacent cervical vertebrae are forced together at the level of
maximum stress and the anteroinferior edge of the upper vertebral
body is driven into the one below, sometimes splitting it in two. The
posterior part of the fractured body is displaced backward and
compresses on the cord
Mechanisms of Injury
– Vertical compression and retroflexion
(hyperextension)
• Stress is mainly on the posterior elements, which may
fractured, and on the anterior ligaments. This allows for
displacement of one vertebral body on the adjacent one.
– Whiplash or recoil injury
• Sudden forward flexion of the neck followed by retroflexion
• Transient posterior dislocation of a vertebral body or
retropulsion of the intervertebral disc into the spinal canal
– High velocity missile penetrates the vertebral canal
and damages the spinal cord directly
Mechanisms of Injury
• Most common sites of vertebral injuries
– 1st and 2nd cervical vertebrae
– 4th to 6th cervical vertebrae
– T11 to L2 vertebrae
• Most mobile portions and the regions in
which the cervical and lumbar
enlargements greatly reduce the space
between neural and bony structures
Mechanisms of Injury
2. Radiation injury of the spinal cord
• Well recognized sequela of radiation
therapy
– Transient radiation myelopathy
– Delayed progressive radiation myelopathy
3. Spinal cord injury due to electric currents
and lightning
4. Myelopathy following lumbar puncture
Mechanisms of Injury
5. Spinal tumors
6. Demyelinating diseases (MS, transverse
myelitis)
7. Infectious myelitis including Pott’s disease
8. Degenerative joint diseases e.g. cervical spondylosis
9. Vascular diseases of the spinal cord
– Infarction
– Hemorrhage of the spinal cord and spinal canal
– Vascular malformations
10. Hereditary disorders e.g. familial spastic paraplegia
11. Congenital disorders e.g. tethered cord
Clinical syndromes
Complete cord transection
syndrome
– Caused by fracture dislocation
of the vertebral column, bullet
or stab wound, or an
expanding tumor
– Bilateral flaccid paralysis and
muscular atrophy at the level
of the lesion
– Bilateral spastic paralysis
below the level of the lesion
– Bilateral loss of all sensation
below the level of the lesion
(pain and temperature loss 12 segments below the lesion)
– Loss of voluntary bowel and
bladder control
Clinical syndromes
Central cord syndrome
– Generally occur in the cervical
area
– Occurs in elderly with DJD in
the neck following
hyperextension injury;
syringomyelia
– Greater UE spastic weakness
than LE
– Segmental loss of pain and
temperature
– Bilateral atrophic, areflexic
paralysis due to involvement of
the AHC
– Bilateral loss of all sensations
below the level of the lesion with
characteristic “sacral sparing”
Clinical syndromes
Brown-Sequard syndrome
– Lateral hemisection of the cord
e.g. bullet, knife wound,
expanding tumor
– Ipsilateral spastic paralysis below
the injury
– Ipsilateral loss of vibration and
position sense
– Contralateral loss of pain and
temperature 1 or 2 segments
below the injury
– Ipsilateral flaccid paralysis at
level of injury (AHC)
– Ipsilateral
paresthesia/radiculopathy/
anesthesia in the segment of the
lesion (dorsal root)
– Simple touch maybe unimpaired
Clinical syndromes
Anterior cord syndrome
– Thrombosis of the anterior
spinal artery, herniated
intervertebral disc, cord
contusion during vertebral
fracture or dislocation
– Bilateral flaccid paralysis
at the level of the lesion
– Bilateral spastic paralysis
and loss of pain and
temperature sense below
the lesion
– Intact position and
vibration sense
Clinical syndromes
Posterior cord syndrome
– Thrombosis of the
posterior spinal artery or
vertebral artery
dissection (uncommon)
– Surgery or trauma to the
spine
– Bilateral loss of position
and vibration sense
below the lesion
– Motor function and
sense of pain and
temperature preserved
Stages in Complete
Transection
• Spinal shock
– Lasts 1-6 weeks, average of 3 weeks
– Due to loss of excitatory descending
influences, the findings below the lesions are:
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Loss of somatic sensation
Loss of visceral sensation
Loss of motor function
Loss of muscle tone
Loss of reflex activity
Stages in Complete
Transection
• Stage of Minimal Reflex Activity
– 3-6 weeks
– Characterized by:
• Bulbocavernous reflex (heralds its onset)
• Weak flexor responses to nociceptive stimuli
which begin distally and later proximal
Stages in Complete
Transection
• Stage of Flexor Muscle Spasm (Spasticity)
– 6-16 weeks
– Characterized by:
• Increasing tone in flexor muscles
• Stronger flexor response to nociceptive stimuli which
progressively involve more proximal muscle group
• Triple flexion response – flexion at hip, knee and ankle with
mild nociceptive stimulus or
• Mass reflex response – mild stimulus leads to powerful
bilateral triple response (due to spread of afferent impulses
from one segment to the next and continue to fire even after
the stimulus withdrawal)
Stages in Complete
Transection
• Stage of alternate flexor and extensor
spasticity
– More than 4 months
– Both flexor and extensor spasms occur, but
within relative short time, extensor muscle
tone may be so great that patient can
momentarily support his weight in standing
position
Stages in Complete
Transection
• Stage of predominant extensor spasticity
– More than 6 months
– Characterized by:
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Complete paralysis below lesion
Marked extensor spasticity
Loss of somatic/visceral sensation
Increased MSR
Bilateral Babinski
Clonus in both lower extremities
Bowel and bladder incontinence
Reflex spinal sweating in response to noxious
stimuli
ASIA’s Adaptation of
Frankel’s Classification
Class
Degree
A
Complete
All motor and sensory is absent below the
zone of partial preservation
B
Incomplete,
preserved sensory
only
Preservation of any demonstrable,
reproducible sensations. Voluntary motor
function is absent
C
Incomplete,
preserved motor,
non-functional
Preservation of voluntary motor function
which is minimal and performs no useful
purpose (MMT grade <3)
D
Incomplete,
preserved motor,
functional
Preservation of voluntary motor function
which is useful functionally (MMT grade ≥3)
E
Normal
Return of all motor and sensory functions but
one may still have abnormal reflexes
Complications of SCI
• Neurogenic bladder
– UMN type – lesion above S2 level
– LMN type – lesion at S2-S4
– Cystometry offers the best diagnostic tool for
differentiation UMN from LMN
– Reflex tests to differentiate
Reflex test
Bulbocavernous
External rectal
sphincter
Anocutaneous
UMN
LMN
+++
Spastic
Lax
Anal wink
-
Complications of SCI
• Long term indwelling or suprapubic catheter
complications
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UTI (most common morbidity)
Epididymo-orchitis
Urethral diverticuli
Vesicovaginal or penoscrotal fistula
Bladder calculi
• Intermittent catheterization program – retraining
the bladder to function on its own
Complications of SCI
• Methods of stimulating micturition
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Stroking or tapping the upper medial thigh
Alternate hot and cold compress
Sound of water from the faucet
Gentle pulling of the pubic hair
Insertion of gloved finger into the anus to relax the
sphincter
• Residual urine determination
– %RU = [RU/(RU+VU)] x 100
• If %RU is < 20%, trial with catheter out
• If %RU is > 20%, reinsert indwelling catheter or continue
ICP
Complications of SCI
• Neurogenic bowel
– Decreased intestinal activity
– Diarrhea caused by fecal impaction
– Bowel program
• Food
– High residue diet
– Fruits
• Fluid intake
– 8-12 liters
• Stool softeners
• Timing
– Postprandial (gastrocolic reflex)
– Assists: suppositories, digital stimulation, laxatives
– Regularity: early morning/evening
• Positioning
– Sitting down (physiologic position)
Complications of SCI
• Autonomic hyperreflexia
– Complication in lesions above T6
– Signs and symptoms
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Pilomotor erection
Hypertension
Headache
Pallor
Dyspnea
Sweating
• Cold extremities
below the level of lesion
• Bradycardia
• Flushing above the
level of lesion
• Hot above the level of
lesion
– Management:
• Since bladder distention is the most frequent cause, urinary
drainage should be established immediately
• Rule out causes from the intestinal tract
Complications of SCI
• Spasticity
– Aggravated by noxious stimuli below the
level of the lesion e.g. skin lesions, ischemic muscle
areas or irritation from the bowel and bladder
– 3 characteristic patterns
• Increased myotatic reflexes
• Resistance to passive range of motion
• Clonus and Babinski
Complications of SCI
Modified Ashworth Scale for Grading Spasticity
Grade Description
0
No increase in muscle tone
1
Slight increase in muscle tone manifested by a check & release or
by minimal resistance at the end of the ROM when the affected
parts is moved in flexion or extension
1+
Slight increase in muscle tone manifested by a catch, followed by
minimal resistance throughout the remainder (less than half) of the
ROM
2
More marked increase in muscle tone, through most of the ROM but
the affected parts easily moved
3
Considerable increase in muscle tone, passive movement difficult
4
Affected parts rigid in flexion or extension
Complications of SCI
• To allow good circulation to insensitive
muscles, self-stretching exercises are
recommended
• If spasticity interferes with functional
activity, medications should be given
– Diazepam, baclofen, tizanidine, dantrolene
• Neurological procedures
– Botulinum toxin injection
– Intrathecal alcohol block, rhizotomy,
myelotomy
Complications of SCI
• Pressure ulcers (decubitus ulcers, bed
sores, pressure sores)
– Area of unrelieved pressure over a defined
area, usually over a bony prominence,
resulting in ischemia, cell death and tissue
necrosis
– Most important etiologic factor is localized
ischemia due to excessive pressure
– Secondary factors: sensory loss, paralysis,
joint contractures, spasticity, incontinence
Complications of SCI
• Sites of occurrence (depends on
positioning of patient)
– Ischial tuberosities (if in sitting position)
– Greater trochanter (if in lateral decubitus
position)
– Sacrum (if lying on back)
– Heels
– Others: knees, lateral malleoli, scapulae,
spinous process, occiput, head of fibula,
ASIS and patella
Complications of SCI
Classification and Staging of Decubitus Ulcers
Stage
Description
1
Non-blanchable erythema not resolved in 30 minutes;
epidermis intact; reversible with intervention
2
Partial thickness loss of skin involving epidermis,
possibly into dermis; may appear as blisters with
erythema
3
Full thickness destruction through dermis into
subcutaneous tissue
4
Deep tissue destruction through subcutaneous tissue
to fascia, muscle, bone, or joint
Complications of SCI
• Prevention
– Turning every 2 hours and inspecting skin
– Relieve pressure
– Spread weight
• Treatment
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High protein, high vitamin
No pressure on the decubitus
Debridement of all devitalized tissues
Medications
Plastic surgical repair
Complications of SCI
• Cardiovascular complications
– Orthostatic hypotension
• Seen in those with lesions above T6
– Edema of the lower extremities
• Due to poor tissue turgor
• Loss of compressible muscle force
• Treatment: compressive stockings
– Thrombophlebitis with pulmonary embolism
• Fatal in 2-5%
• Treatment: prophylactic anticoagulation
Complications of SCI
• Respiratory complications
– Pulmonary atelectasis
– Pulmonary infection
– Pulmonary edema
• Treatment: mechanical ventilation, tracheostomy,
respiratory therapy (breathing exercises, postural
drainage), antibiotics, etc
Complications of SCI
• Metabolic and Endocrinologic complications
– Hypoproteinemia
– Hormonal levels, including adrenal and sex
hormones, change immediately following injury but
resolve within weeks or months
– Testicular atrophy with impaired spermatogenesis
• Abnormal temperature regulation of the scrotum
• Pituitary-gonadal feedback changes
• Frequent infection of the urogenital tract
– Osteoporosis can lead to fractures
– Immobilization hypercalcemia
– Treatment: adequate hydration, reduced calcium
intake, trial with steroids or oral phosphatase,
furosemide and mithramycin
Case
• A 65 year old woman was admitted because of
progressive lower extremity weakness
• HPI:
– Three months prior to admission, she started to
experience moderately severe nape pain. This was
followed a week after by numbness of right foot
ascending to the right leg and thigh.
– Two months prior to admission, she also noted
weakness of the right leg described as dragging of
the right foot when walking. She also noticed
ascending numbness on the left lower extremity.
– One month prior to admission, she was only able to
walk with the help of a stick
– Five days prior to admission, she was no longer able
to walk.
• Neurological exam
– No cognitive impairment
– Cranial nerve examination
• Left pupil: 3-4 mm RTL
• Right pupil: 1-2 mm RTL, with mild ptosis
– Weak hand grip on both sides but power was normal
on the proximal segments of the upper extremities
– Both lower limbs showed weakness with increased
muscle tone, especially on the right
– Knee jerks and ankle jerks in both lower limbs were
grossly exaggerated and there was bilateral extensor
toe responses
– Loss of pain sensation below the nipple on both sides
of the body
– Postural and vibration sense were impaired in both
great toes
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