Which of the following is a common cause of neurogenic shock?

Neurogenic shock is primarily caused by a disruption in the sympathetic nervous system due to damage to the spinal cord. When the spinal cord is injured, particularly in the cervical or upper thoracic regions, the body loses the ability to maintain vascular tone, resulting in widespread vasodilation. This excessive dilation leads to reduced blood return to the heart and decreased blood pressure, which characterizes neurogenic shock.

In cases of spinal cord injury, the autonomic control that maintains vascular resistance is impaired, causing a sudden drop in systemic vascular resistance and ultimately leading to shock. This situation is compounded by bradycardia, or a slower heart rate, due to unopposed vagal tone from the disrupted sympathetic output.

Other options presented do not directly lead to neurogenic shock. Severe dehydration is more likely to lead to hypovolemic shock, hemorrhagic events also lead to hypovolemic shock due to blood loss, and allergic reactions cause anaphylactic shock, which involves different mechanisms primarily related to histamine release and anaphylaxis. Therefore, spinal cord injury is the primary condition associated with neurogenic shock, distinguishing it clearly from these other causes.