Shock - Neurogenic: Nursing

Shock is a life-threatening condition that occurs when the organs don’t receive enough oxygen and nutrients to function properly. Shock can be grouped into four types based on the cause: hypovolemic, cardiogenic, obstructive, and distributive shock. Neurogenic shock is a type of distributive shock where damage to the brain or spinal cord causes dysregulation of the cardiovascular system, leading to decreased heart rate and vasodilation, which eventually leads to impaired tissue perfusion.

Now, to understand the neurogenic shock, let’s quickly review the physiology of blood vessels, which contain smooth muscle in their walls. When the smooth muscle relaxes, it increases the diameter of blood vessels, called vasodilation. On the other hand, when smooth muscle contracts, the diameter of blood vessels decreases, called vasoconstriction.

The contraction and relaxation of smooth muscles are primarily controlled by the sympathetic nervous system, which normally maintains a partial constriction, generating enough force to keep blood moving through the circulatory system. The sympathetic system stimulation can increase or decrease to keep up with the body’s needs. Increased sympathetic stimulation of the blood vessels causes increased heart rate and vasoconstriction, which increases peripheral vascular resistance. Vasoconstriction, when the total blood volume is constant, raises blood pressure and allows blood to flow faster through the blood vessels. In contrast, decreased heart rate and vasodilation is typically caused by decreased sympathetic stimulation, in addition to inflammatory cytokines and histamine, which decrease peripheral vascular resistance. So, vasodilatation, when blood volume is constant, lowers the blood pressure and slows down the blood flow through the blood vessels.