SCI Flashcards
Damage to the spinal column may occur without injury to the cord, or it can cause SCI through which 3 mechanisms?
- compression
- hemorrhage
- traumatic vasospasm
Compression, hemorrhage or traumatic vasospasm to the cord may result in _______________________.
Ischemia/infarction
What is traumatic SCI frequently associated with?
- systemic hypotension
- reduced spinal cord perfusion pressure
T/F Systemic hypotension may contribute to secondary ischemic neurologic injury and should be avoided.
True
What two things can cause hypotension that exacerbates secondary injury to the spinal cord?
Hemorrhage and neurogenic shock
When does secondary SCI peak at?
4-6 days
During the acute phase of SCI what happens concerning sympathetic innervation?
Systemic vasodilation from loss of sympathetic tones occurs in increasing severity with ascending levels of SCI above L2, leading to hypotension
During the acute phase of SCI, what complicates things with injuries above T6?
Bradycardia d/t compromise of the sympathetic cardiac accelerator fibers
What happens during neurogenic shock?
- diminished effect of sympathetic pathways
- loss of vasomotor tone and diminished sympathetic innervation of the heart
- vasodilation of blood vessels (visceral and lower extremity)
- pooling of blood leading to hypotension and bradycardia
What is the treatment for neurogenic shock?
fluid resuscitation
+/- vasopressors
+/- atropine
What happens during spinal shock?
Temporary features of lower motor neuron lesions: - flaccidity - paralysis - loss of reflexes —> with resolution within 24 hours **
What is the clinical marker of spinal shock?
Bulbocavernous reflex
When is the prognosis based on neurologic exams most reliable for spinal shock?
72 hours - 1 week following trauma
What is autonomic hyperreflexia?
A chronic neurologic disorder that occurs in association with resolution of spinal shock and a return of spinal cord reflexes
During autonomic hyperreflexia what initiates afferent impulses that are transmitted to the spinal cord below the level of spinal cord transection?
Cutaneous or visceral stimulation (such as distention of the urinary bladder or rectum)
During autonomic hyperreflexia, cutaneous or visceral stimulation elicits a reflex sympathetic response that results in:
Intense generalized vasoconstriction and hypertension
During autonomic hyperreflexia, what is a secondary occurrence to HTN?
Bradycardia d/t activation of baroreceptor reflexes
The incidence of autonomic hyperreflexia during general anesthesia depends on:
The level of spinal cord transection
Approximately _____ of patients with spinal cord transection above ____________________ will exhibit autonomic hyperreflexia during general anesthesia.
85%
The T6 dermatome
It is difficult to illicit autonomic hyperreflexia in patients with spinal cord transection below the ______ dermatome.
T10
How do you treat autonomic hyperreflexia?
PREVENTION!
- neuraxial block, either SAB or Epidural
Direct acting vasodilators
- nitroprusside
- nitroglycerin
What takes place during upper motor neuron injury?
- spastic paralysis
- NOT associated with muscle atrophy
- hyperreflexia
What is an example of an upper motor neuron injury?
Cerebral palsy
What takes place with lower motor neuron injury (peripheral nerves)?
- flaccid paralysis
- associated with muscle atrophy
- hyporeflexia
What happens when motor pathways in the lumbar area are injured (L1-S5)?
- Injury to L2 and above causes spastic paralysis of the lower extremities
- injury causes bowel, bladder and sexual dysfunction
What happens when motor pathways of the thoracic area are injured (T1-T12)?
- Injury causes the same deficits as lumbar injury
- T9 - T12 causes loss of trunk and abdominal muscle control
What is unique to injury of the thoracic area above T6?
- autonomic dysreflexia
- neurogenic shock: loss of vascular muscle tone
- T1-T4 are the cardiac accelerator fibers
- can cause disruption of body temperature regulation
What happens during motor pathway injury to the cervical area (C1-C8)?
Injury causes same deficits as thoracic injury
- C3-C5 innervate the diaphragm
- C1-C4 injury causes quadriplegia and need for mechanical ventilation
- C5 and above, pt will have difficulty clearing secretions
