Topic 24 Spinal cord injury and lesion Flashcards
List the different types of injury to the spinal cord – traumatic or pathological
o Traumatic ( MVA, MBA, water related, sporting, falls, violence)
o Infectious
• acute: e.g. staphylococcal
• chronic: e.g. TB
o Disc disease and spondylosis
o Haematoma
• AVM, spontaneous, trauma
o Cystic lesions
-extradural
-intradural (arachnoidal)
-intramedullary (syringomyelia)
o Tumours (primary or secondary)• Thoroughly understand and describe the term ‘spinal shock’
Lasts 24 Hrs to 4/52
o Following acute, severe damage to the spinal cord - all cord function below the level of the lesion becomes depressed or lost ( does not always occur in low thoracic and lumbar spine lesions)
o Anaesthesia - loss of all sensation ensues
o Paralysis ensues - flaccid paralysis and absent DTRs
o Segmental spinal reflexes depressed due to removal of higher centre influence: i.e. from cerebrum and brainstem: corticospinal, reticulospinal, tectospinal, rubrospinal and
vestibulospinal tracts etc.
o Paralysis of the bladder and rectum - initially the bladder is atonic and an IDC is inserted to promote unobstructed drainage and decrease the risk of retention of urine (UTIs) - fluid restrictions are set
o Paralysis of the rectum - lax anal sphincter - avoid fluids and food until medical staff are satisfied that GIT is active
o Sympathetic changes: sympathetic motor neurons exit the SC between T1-L2. Interruption causes hypotension from loss of sympathetic vasomotor tone (↓BP). Sympathetic changes also may include bradycardia and poikilothermia
o Treated with high-dose corticosteroids to avoid ascending injury and to minimise the effects of primary injury
RECOVERY
o As shock diminishes, neurons regain excitability and the effects of the UMN loss on the segments below the level of the lesion will appear
o Reflex functions of the cord become progressively restored and UMN signs appear. Muscle tone below the level of the lesion becomes spastic. DTRs become increased. A positive Babinski can be elicited on both sides. Ankle clonus is evident.
o Postural hypotension may persist - i.e. when raised from the recumbent position, owing to interruption of the baroreceptor reflex, BP drops. Wearing an abdominal binder may be sufficient to compensate for the lost reflex.
o Autonomic reflex arcs involving relay to secondary ganglionic neurons outside the spinal cord may be variably affected during spinal shock, and their return after spinal shock abates is variable. The returning spinal cord reflex arcs below the level of injury are irrevocably altered and are the substrate on which rehabilitation efforts are based.
o Spinal shock is currently attributed to a generalised hyperpolarisation of spinal neurons below the level of the lesion, perhaps because of a large-scale release of the inhibitory neurotransmitter glycine
Define Paraplegia:
Impairment or loss of motor and/or sensory function in the thoracic, lumbar or sacral segments of the spinal cord,
secondary to damage of neural elements within the spinal canal
which results in partial to complete deficit of motor and/or sensory function in areas supplied by these neurological levels.
Define Quadriplegia/tetraplegia
impairment or loss of motor and/or sensory function in the cervical segments of the spinal cord due to damage of neural elements within the spinal canal
Define complete and incomplete spinal injury
Complete: “absence of sensory and motor functionin the lowest sacral segment”
Incomplete: “partial preservation of sensory and/or motor functions is found below the neurological level and includes the lowest sacral segment”
Define syringomyelia:
a chronic progressive disease in which longitudinal cavities form in the cervical region of the spinal cord. This characteristically results in wasting of the muscles in the hands and a loss of sensation.
Which 3 ways are spinal cord injuries classified?
Paraplegia v Quadriplegia (Tetraplegia)
2. Complete v Incomplete
3. Level
Level of the neurological level of injury is determined by the lowest normally functioning (motor and sensory) spinal cord segment – bilaterally
e.g. T10 complete paraplegic: o T10 is the lowest normally functioning level o the injury shows absence of sensory and motor function in the lowest sacral segment o impairment or loss of motor and/or sensory function in the thoracic segment of the spinal cord (T10) – hence paraplegic
• Describe primary damage to the spinal cord following a traumatic SCI and list the pathological changes observed
Initial mechanical trauma includes traction and compressive forces
o Direct compression of neural elements by fractured and displaced bone fragments, disc material and other tissue injures nervous system
o Blood vessels are damaged, axons disrupted, and neural cell membranes broken
o Microhaemorrhages occur within minutes and spread radially and axially within the next few hours
o Within minutes the spinal cord swells at the injury level (can occupy the canal)
o Secondary ischaemia results when cord swelling exceeds venous blood pressure
o Autoregulation of blood flow ceases
o Leads to spinal shock
o Systemic hypotension occurs which leads to more ischaemia
o Ischaemia, release of toxic chemicals from disrupted neural membranes and electrolyte shifts (Na+, K+, Ca2+) → trigger a secondary injury cascade
• Describe secondary changes to the spinal cord following a SCI and list the pathological changes observed
The release of toxic chemicals and excitatory amino acids, such as free radicals and glutamate follows
o Activation of harmful enzymes → apoptosis (self‐programmed cell death) or necrosis that extends to white matter of the spinal cord
o In approximately 25% of SCIs a cyst develops that may expand and lead to syringomyelia
• Describe the clinical presentation of a patient with a SCI – consider differences depending on the level of the lesion
UMN lesions: Result from damage to cortical neurons that give rise to corticospinal and corticobulbar tracts
o LMN lesions: Result from damage to motor neurons in the anterior horn or motor neurons of cranial nerve nuclei - an interruption of the final common pathway connecting the neuron via its axon with the muscle fibres it innervates.
LMN signs: at the level of the lesion / level of the injury due to interruption of the final common pathway
UMN signs: below the level of the lesion / level of the injury due to interruption of the corticospinal tracts
List UMN ss & LMN ss
Poikilothermia (coldblooded) / poor thermoregulation
Autonomic Dysreflexia (‘mass reflex’)
Orthostatic hypotension
Neurogenic/neuropathic pain
Poikilothermia define
Poikilothermia (coldblooded) / poor thermoregulation
Patients with a SC lesion above T1-6
Inability to regulate temperature due to a disturbance to the connections to the sympathetic nervous system
-when the outside temperature is hot, patient cannot normally dilate the blood vessels and sweat appropriately in an attempt to cool the inside temperature of the body
-when the outside temperature is cold, patient’s body cannot normally constrict the blood vessels in an attempt to conserve heat
Signs of heat stroke
Signs of Hypothermia
Signs of heat stroke:
o High body temperature
o Rapid pulse
o Dry, flushed skin
Signs of hypothermia: o Irritability o Mental confusion o Hallucinations o Lethargy o Clumsiness o Slow respiration o Slow pulse
Autonomic Dysreflexia
Autonomic Dysreflexia (‘mass reflex’)
BP increases, increased sweating, headache
o Often accompanies SCI especially above T6 – excessive activity of SNS
o Elicited by noxious stimuli to body, especially to the skin and viscera below the level of the lesion
o Frequently occurs in response to distention of the bladder or rectum
o Bladder related in 85% of cases – from overdistention, catheter blockage, UTIs, decubitus ulcers, ingrown toenails, cutaneous stimulation, spontaneous and induced muscle spasms, ROM Xs …
o Pathophysiology not fully understood
o Physiotherapy: careful not to induce autonomic dysreflexia – harmful & life threatening
o Treatment: identify and remove trigger stimulus, elevate patient’s torso to
increase venous pooling in legs → decreases cardiac output
Orthostatic hypotension
Definition: a 20mmHg or greater fall in systolic BP or a 10mmHg or greater fall in diastolic BP on upright position
o Caused by loss of sympathetic vasoconstriction in SCI and by loss of muscle pump in venous return
Neurogenic/neuropathic pain
Local pain: arises from bony and soft tissues surrounding the level of the lesion (especially following SCI due to # or infarction,herniation)
o Radicular pain: created by damage to sensory nerve roots; often associated with local pain; usually radiates in a dermatomal pattern
o Diffuse aching and burning pain (neurogenic pain): attributed to dysfunction of spinal cord pathways. Most frequently seen in traumatic SCI patients; usually develops late – often months post-injury; not localised – referred to well below level of lesion – buttocks, legs and feet
