Neurogenic shock


Neurogenic shock

Neurogenic shock is a distributive type of shock resulting in hypotension, occasionally with bradycardia, that is attributed to the disruption of the autonomic pathways within the spinal cord. Hypotension occurs due to decreased systemic vascular resistance resulting in pooling of blood within the extremities lacking sympathetic tone. Bradycardia results from unopposed vagal activity and has been found to be exacerbated by hypoxia and endobronchial suction.[1] Neurogenic shock can result from severe central nervous system damage (brain injury, cervical or high thoracic spinal cord).[2] In more simple terms: the trauma causes a sudden loss of background sympathetic stimulation to the blood vessels. This causes them to relax (vasodilation)[3] resulting in a sudden decrease in blood pressure (secondary to a decrease in peripheral vascular resistance).

Neurogenic shock can be a potentially devastating complication, leading to organ dysfunction and death if not promptly recognized and treated. It is not to be confused with spinal shock, which is not circulatory in nature.

Treatment

  • Fluid is always the initial treatment of shock, especially since concomitant hemorrhagic shock must be excluded following trauma. Most institutions will additionally utilize pressor agents to achieve hemodynamic stability.
  • Dopamine (Intropin) is often used either alone or in combination with other inotropic agents.
  • Vasopressin (antidiuretic hormone [ADH])[4]
  • Certain vasopressors (ephedrine, norepinephrine). Phenylephrine should be avoided as it can worsen bradycardia often seen in neurogenic shock.
  • Atropine (speeds up heart rate and cardiac output)

References

  1. ^ J.M. Piepmeyer, K.B. Lehmann and J.G. Lane, Cardiovascular instability following acute cervical spine trauma, Cent Nerv Syst Trauma 2 (1985), pp. 153–159.
  2. ^ 4. Guly HR, Bouamra O, Lecky FE. The incidence of neurogenic shock in patients with isolated spinal cord injury in the emergency department. Resuscitation (2008) 76, 57-62
  3. ^ "Dorlands Medical Dictionary:neurogenic shock". http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/seven/000096569.htm. 
  4. ^ http://www.health.am/vein/more/hypotension_shock_treatment/

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