What autonomic dysfunction risk is associated with high-level spinal cord injury?

• A. Autonomic hyperreflexia
• B. Polyuria
• C. Hypoxic encephalopathy
• D. Neurogenic shock: hypotension and bradycardia due to loss of sympathetic tone

Answer: (D)

High-level spinal cord injury cuts off the sympathetic nerves that normally run from the thoracic region to the body below the injury. In the acute phase this leaves the body with little or no sympathetic tone below the injury, causing neurogenic shock. The loss of sympathetic input leads to widespread vasodilation and hypotension, while the heart rate drops because unopposed parasympathetic (vagal) activity slows the heart. This scenario is a direct autonomic dysfunction risk associated with high-level injury. Autonomic hyperreflexia can occur later after spinal shock has resolved and is driven by an exaggerated sympathetic response to stimuli, leading to high blood pressure rather than the hypotension and bradycardia seen in neurogenic shock. The other options don’t reflect the immediate autonomic failure caused by the high-level injury.