A kinked catheter during an acute spinal cord injury episode triggered autonomic dysreflexia; which explanation BEST accounts for the improvement after straightening the tubing?

A kinked catheter during an acute spinal cord injury episode triggered autonomic dysreflexia; which explanation BEST accounts for the improvement after straightening the tubing?

• A. Reducing venous return to the heart
• B. Straightening the tubing allowed resumption of bladder filling
• C. The kinked catheter was preventing sympathetic outflow
• D. The kinked catheter caused bladder distension, which was the noxious stimulus triggering the sympathetic response below the lesion

Answer: (D)

Autonomic dysreflexia arises when a noxious stimulus below the level of a spinal cord injury triggers an uncontrolled sympathetic reflex, causing dangerous high blood pressure. A kinked catheter blocks bladder drainage, leading to bladder distension. That distension acts as a strong noxious stimulus that travels to the spinal cord and, because supraspinal inhibition is lost below the injury, unleashes a massive sympathetic response. This response constricts blood vessels below the lesion, raising blood pressure and producing symptoms like headache and flushing above the level of injury. When the tubing is straightened, bladder drainage resumes and the irritating distension is relieved. The stimulus driving the sympathetic storm disappears, so the excessive vasoconstriction abates and blood pressure and symptoms improve. Other options don’t fit as well because they don’t reflect the triggering mechanism. Simply changing venous return doesn’t address the bladder distension driving the reflex, and allowing bladder filling would worsen the distension. The kinked catheter isn’t blocking sympathetic outflow; the problem is an exaggerated sympathetic response to a noxious below-lesion stimulus, which is resolved by removing the obstruction and the stimulus.

Autonomic dysreflexia arises when a noxious stimulus below the level of a spinal cord injury triggers an uncontrolled sympathetic reflex, causing dangerous high blood pressure. A kinked catheter blocks bladder drainage, leading to bladder distension. That distension acts as a strong noxious stimulus that travels to the spinal cord and, because supraspinal inhibition is lost below the injury, unleashes a massive sympathetic response. This response constricts blood vessels below the lesion, raising blood pressure and producing symptoms like headache and flushing above the level of injury.

When the tubing is straightened, bladder drainage resumes and the irritating distension is relieved. The stimulus driving the sympathetic storm disappears, so the excessive vasoconstriction abates and blood pressure and symptoms improve.

Other options don’t fit as well because they don’t reflect the triggering mechanism. Simply changing venous return doesn’t address the bladder distension driving the reflex, and allowing bladder filling would worsen the distension. The kinked catheter isn’t blocking sympathetic outflow; the problem is an exaggerated sympathetic response to a noxious below-lesion stimulus, which is resolved by removing the obstruction and the stimulus.