After spinal cord injury, the disruption of descending vasomotor pathways to sympathetic
neurons causes their hyperexcitability. When irritated by noxious stimuli below the level of
injury, a massive sympathetic reflex is triggered, causing widespread vasoconstriction. If
the neurological level of injury is at or above T6, this vasoconstriction can lead to
progressive hypertension possibly involving the splanchnic vessels.
In response to hypertension, the baroreflex system lowers blood pressure by reducing heart
rate and decreasing the activity of sympathetic neurons. However, a decrease in peripheral
vascular resistance below the injury level does not occur because of the disruption of
descending vasomotor pathways to sympathetic neurons. Thus, hypertension persists until the
triggering stimulus is removed. Hypertensive crises can result in vascular complications like
cardiac arrest, retinal or subarachnoid hemorrhages, stroke, and even death. Vasodilatation
above the lesion level is accompanied by characteristic signs and symptoms such as upper body
flushing and sweating, and a pounding headache. Sometimes bradyarrhythmia, seizures, nausea,
or anxiety can occur. Unfortunately, AD can take place asymptomatically in almost 40 %. These
asymptomatic individuals are at high risk of life-threatening complications mentioned above.
The most frequent AD triggers are overfilled bladder or bowel. Nevertheless, it can be any
irritating stimuli below the level of injury, i.e., skin lacerations, ingrown toenails, or
pressure sores.
Higher intensity of perception of clinical symptoms accompanying AD decreases the risk of
vascular complications. People who perceive subjective signs of AD even in slightly elevated
blood pressure can eliminate irritating stimuli or use an antihypertensive medication and
thus avoid life-threatening complications. On contrary, people who cannot perceive the signs
intensely enough are at a significantly higher risk of vascular complications.
The aim of this study is to determine the risk level of vascular complications in SCI people.
The AD will be triggered below the injury level so that the clinical symptoms can be
correlated with their subjective individual perception. Moreover, the development of a method
allowing capturing AD episodes in individuals without subjective signs is intended.
