Injury at or above which level most commonly causes hypotension and bradycardia due to autonomic disruption?

• A. T6 or higher
• B. T12
• C. L2
• D. C7

Answer: (A)

When the spinal cord is injured high in the thoracic or cervical region, the brain’s descending control of the sympathetic nervous system to the heart and blood vessels is lost. This leaves the heart under unopposed parasympathetic (vagal) influence and causes widespread vasodilation because the sympathetic vasoconstrictor pathways are gone. The result is neurogenic shock, characterized by low blood pressure and a slow heart rate. This pattern is most commonly seen with injuries at or above the T6 level because those upper-level pathways to the heart and major vessels are disrupted, leading to the bradycardia and hypotension described. Below this level, some sympathetic tone remains, so the same combination of bradycardia and hypotension is less typical.