Neurogenic shock

Background

• Do not confuse with Spinal Shock
• Diagnosis of exclusion
  • Never presume hypotension in trauma patient is due to neurogenic shock
• Injury to cervical or thoracic vertebrae causes peripheral sympathetic denervation
  • Above T1: full sympathetic denervation
  • T1-L3: Partial sympathetic denervation
  • Below L4: no sympathetic denervation
• Lasts 1-3 wk

Evaluation

• Hypotension(well tolerated)
• Bradycardia
• Peripherally vasodilated (warm extremities)
  • However, this leads to hypothermia
  • Ensure monitoring of core temperatures and warming of patient

Differential Diagnosis

Shock

• Cardiogenic
  • Acute valvular Regurgitation/VSD
  • CHF
  • Dysrhythmia
  • ACS
  • Myocardial Contusion
  • Myocarditis
  • Drug toxicity (e.g. beta blocker, CCB, or bupropion OD)
• Obstructive
  • Air embolism
  • Aortic Stenosis
  • Cardiac Tamponade
  • PE
  • Tension pneumothorax
• Distributive
  • Adrenal crisis
  • Anaphylaxis
  • Neurogenic shock
  • Sepsis
  • Toxicologic
• Hypovolemic
  • Severe dehydration
  • Hemorrhagic shock (traumatic and non-traumatic)

Management

1. Exclude other causes of shock
2. Supplemental O2 to perfuse injured spinal cord
3. Mechanical ventilation and oxygenation if spinal perfusion is compromised
4. Prevent hypothermia
5. Judicious IVF, with UOP > 30 cc/hr
6. Norepinephrine first line, with MAP goal of 85-90 for the first 7 days after spinal cord injury
   1. Consider adding phenylephrine if BP refractory to first line agent
   2. Phenylephrine alone without beta-1 stimulation will cause reflex bradycardia
   3. Atropine if needed, keeping HR 60-100 bpm in NSR
   4. May titrate down on norepinephrine and atropine, to favor more phenylephrine alpha agonism in ICU setting
7. High risk of VTE in paraparesis or tetraparesis
   1. Up to 40% in non-prophylaxed
   2. Must weigh benefits of VTE prophylaxis and risk of bleed from LMWH
   3. Low dose SC heparin at 500 units q8hrs plus SCDs may be alternative

References

• Chin LS et al. Spinal Cord Injuries Treatment & Management. Jul 7, 2015. http://emedicine.medscape.com/article/793582-treatment#showall.
• Coplin WM. Traumatic Spinal Cord Injury. 2013 Neurocritical Care Society Practice Update. http://www.neurocriticalcare.org/sites/default/files/pdfs/09.SCI.final.pdf.

• Orlando Regional Medical Center. Vasopressor and Inotrope Usage in Shock. 4/19/2011. http://www.surgicalcriticalcare.net/Guidelines/Vasopressors%20and%20Inotropes%20in%20Shock.pdf.

See Also

• Spinal Cord Trauma
• Spinal Cord Compression (Non-Traumatic)
• Autonomic Dysreflexia
• Spinal Shock

Authors

Kevin Lu, Jordan Swartz, Ross Donaldson, Neil Young, Daniel Eggeman, Daniel Ostermayer