Spinal Shock and Neurogenic Shock - Dr. Asimos

HIGH YIELD CONCEPTS:

• “Neurogenic Shock” (Neurogenic Hypotension) refers to a loss of BP regulation (hypotension and bradycardia) following a complete SCI above the T5 level and is due to loss of sympathetic outflow to the systemic vasculature and heart.
• “Spinal shock” is a neurologic phenomenon that generally lasts < 24 hours in the acute phase of a SCI and is best described as a transient physiologic reflex depression of cord function below the level of injury, resulting in loss of all sensorimotor functions.
• A Central Cord Syndrome is the most common incomplete SC lesion, usually resulting from forced hyperextension in the setting of cervical spine DJD or spinal stenosis, and classically manifests as paresis mostly in the distal upper extremities with dysesthesias in a “cape-like” distribution.

Basics

• Spine - 2 column concept; flexion - crush the front open the back, extension, crush the back and open the front; axial load - Jefferson fracture = unstable; rotational injuries - unilateral facet is stable; bilateral facet injury is unstable; Distraction injury - can cause hangmans fracture
  
  
• Things to be aware of that can lead to spinal cord injury - Fracture, joint dislocation, ligamentous tearing, disc protrusion
  
  
• Neurogenic shock = functional sympathectomy - high cord injury - lose sympathetic innervation. Also have parasympathetics unopposed - results in bradycardia and hypotension; look at the bladder as well because urination is a parasympathetically innervated - spinal cord injury = brisk bladder reflex.
  

• Spinal shock - neurologic phenomena loss of all neurolgoic function in the acute phase of a SCI > lasts < 24 hrs

Management

• Optimizing return of neurologic function - immobilization - variable evidence; avoiding hypotension, hypoxemia, and hyperthermia
  
  
• Neurologic HPI - details of event causing injury, transient or persistent numbness weakness or paresthesias, neck or back pain, prior history of spinal stenosis - predisposes to central cord, arthritis, previous spinal fusion
  
  
• Airway management - intubate fast and early > C3-C5 = diaphragm; patient can recruit some accessory muscles but won't last long
  
  
• Make sure neurogenic hypotension is a diagnosis of exclusion in the trauma patient - these patient's shouldn't be tachcyardic with hypotension and they should have obvious signs of spinal cord injury
  
  
• Neurogenic hypotension - typically respond to Trendelenburg position & IVF
  
  

       >  Avoid phenylephrine as a pressor (concern over reflex bradycardia); Choose NE vs dopamine

• Acute complete cord injury - reduced sensation reduced muscle power
  
  
• Incomplete injury - various degree of motor function; sensation preserved more than motor; bulbocavernosus reflex & anal sensation spared
  
  
• Transient paralysis & spinal shock - younger athletes - will look like a complete injury & can have neurogenic hypotension
  
  
• Incomplete spinal cord lesions - central cord (most commons incomplete SCI) - forced hyperextension - paresis upper > lower;  anterior cord - flexion injuries - paralysis and hypalgesia below level of injury; preservation of posterior column - vibration pressure light touch and proprioception; brown sequard - penetrating lesions - ipsilateral motor paresis, loss of vibration pressure and all propioception; contralateral sensory hypesthesia
  
  
• C5 - elbow flexed, C6 wrist extension; C7 elbow extensor, C8 finger flexors, T1 - finger abduction; know your cord levels and dermatomes!
  

• "Jefferson bit off a hangmans thumb" - unstable C spine fractures
  
  

        - Jefferson - axial load - classic diving injury - unstable fracture

        - Bifacet dislocation

        - Type II odontoid fracture

        - Hangmans fracture - distraction & rotation injury - posterior element of C2 gets fractured & spondylolisthesis of axis

        - Flexion Teardrop - most serious of all Cspine fractures

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