Autonomic dysreflexia is common in people with spinal injuries at or above which level?

Autonomic dysreflexia is common in people with spinal injuries at or above which level?

• A. T10 or higher
• B. C7 or higher
• C. T6 or higher
• D. T4 or higher

Answer: (C)

Autonomic dysreflexia occurs when a spinal cord injury is at or above the sixth thoracic level. When the injury blocks descending inhibitory signals, a noxious stimulus below the level of injury (such as bladder distention or bowel impaction) triggers a reflex, unregulated sympathetic response below the lesion. This causes widespread vasoconstriction and a dangerous rise in blood pressure. The brain can still activate parasympathetic responses above the level of injury, leading to flushing and bradycardia there, but it can’t reverse the hypertension because the signal to relax vessels below the injury cannot get through. The T6 cutoff matters because the major sympathetic outflow to the splanchnic vascular bed resides around T5–T9; injuries at or above T6 disrupt this control, making autonomic dysreflexia possible. Injuries below that level generally do not produce this life-threatening crisis.

Autonomic dysreflexia occurs when a spinal cord injury is at or above the sixth thoracic level. When the injury blocks descending inhibitory signals, a noxious stimulus below the level of injury (such as bladder distention or bowel impaction) triggers a reflex, unregulated sympathetic response below the lesion. This causes widespread vasoconstriction and a dangerous rise in blood pressure. The brain can still activate parasympathetic responses above the level of injury, leading to flushing and bradycardia there, but it can’t reverse the hypertension because the signal to relax vessels below the injury cannot get through. The T6 cutoff matters because the major sympathetic outflow to the splanchnic vascular bed resides around T5–T9; injuries at or above T6 disrupt this control, making autonomic dysreflexia possible. Injuries below that level generally do not produce this life-threatening crisis.