What is the primary cause of neurogenic shock?

Neurogenic shock primarily results from a spinal cord injury due to disruption of sympathetic nervous system pathways that control vascular tone. This disruption leads to vasodilation, resulting in significant hypotension and bradycardia. The loss of sympathetic tone causes blood vessels to become dilated, which can severely reduce blood flow and oxygen delivery to organs and tissues, ultimately compromising their function.

In contrast, cardiac arrest, pneumonia, and stroke do not directly cause the specific pathophysiological changes seen in neurogenic shock. Cardiac arrest typically leads to a lack of perfusion and oxygenation, pneumonia can cause systemic infection and shock but is more related to the inflammatory response, and stroke primarily affects brain function but does not inherently create the loss of sympathetic control that characterizes neurogenic shock. Thus, spinal cord injury stands out as the primary cause due to its direct impact on the autonomic regulation of vascular tone.