Neurogenic shock is defined as shock that occurs after injury to the spinal cord with disruption of sympathetic outflow, resulting in unopposed vagal tone. What is the name of this condition?

Neurogenic shock is defined as shock that occurs after injury to the spinal cord with disruption of sympathetic outflow, resulting in unopposed vagal tone. What is the name of this condition?

• A. Neurogenic shock
• B. Hypovolemic shock
• C. Anaphylactic shock
• D. Septic shock

Answer: (A)

The key idea is that loss of sympathetic vasomotor tone after spinal cord injury allows unopposed parasympathetic (vagal) activity, leading to widespread vasodilation and hypotension. This combination defines neurogenic shock. The heart rate may be relatively slow because the vagal influence isn’t countered by sympathetic drive, and blood may pool in the venous system due to reduced vascular tone. This is the name that fits the described mechanism precisely. It’s different from hypovolemic shock, where the primary issue is low circulating volume and the body typically responds with tachycardia; from anaphylactic shock, which is immune-mediated and usually presents with bronchospasm and urticaria; and from septic shock, which stems from infection and inflammatory vasodilation with capillary leak. In neurogenic shock, the switch is neural loss of sympathetic tone rather than fluid loss or immune/infectious processes.

The key idea is that loss of sympathetic vasomotor tone after spinal cord injury allows unopposed parasympathetic (vagal) activity, leading to widespread vasodilation and hypotension. This combination defines neurogenic shock. The heart rate may be relatively slow because the vagal influence isn’t countered by sympathetic drive, and blood may pool in the venous system due to reduced vascular tone.

This is the name that fits the described mechanism precisely. It’s different from hypovolemic shock, where the primary issue is low circulating volume and the body typically responds with tachycardia; from anaphylactic shock, which is immune-mediated and usually presents with bronchospasm and urticaria; and from septic shock, which stems from infection and inflammatory vasodilation with capillary leak. In neurogenic shock, the switch is neural loss of sympathetic tone rather than fluid loss or immune/infectious processes.