4. Autonomic Dysreflexia

Alert patients with SCI at T6 and above to the risks of Autonomic Dysreflexia, and the need for urgent attention at the onset of an episode.

The Problem

Autonomic Dysreflexia (AD) is a potentially life-threatening condition that affects approximately 80% of people with spinal cord injuries at or above T6. AD occurs when reflex sympathetic activity is triggered by afferent input below the level of the spinal cord lesion. This elevates systemic blood pressure, which can’t be corrected because of the lack of parasympathetic innervation. AD is more severe with higher lesions and more complete injury. Signs and symptoms of AD include:

  • sudden hypertension (an increase in systolic BP >20-40 mmHg above the patient’s usual baseline);
  • headache; and,
  • a constellation of other symptoms, such as sweating, myosis, flushing, bradycardia or tachycardia.

In affected individuals, episodes may occur as many as 20 times a day. The vast majority of episodes are caused by bladder distension or bowel impaction, but have also been found to be caused by skin irritation, sexual activity, or other systemic issues. Iatrogenic triggers may include urological, gastrointestinal or reproductive procedures. Long-standing AD has been shown to be associated with cognitive deficits, stroke, myocardial infarction, retinal detachment, seizure and even death.

Evidence-based Best Practice

Resting BP typically declines after a spinal cord injury, often to about 90/60 mmHg; thus readings of 120/80 mmHg might be considered elevated. Resting BP should be monitored at every visit.

Management of AD is a medical emergency:

  • Place the patient in an upright position; Loosen clothing and other restrictions.
  • Monitor pulse and BP every 2-5 minutes during the episode.
  • earch for and eliminate the precipitating stimulus (eg., bowel or bladder emptying).
  • If systolic BP remains at or above 150 mmHg, consider rapid-onset, short duration anti-hypertensives, such as nifedipine Iimmediate release) , nitrates, and captopril. Avoid nitrates if patient is on PDE5i (such as Viagra).
  • Continue to monitor BP for at least 2 hours after symptoms resolve, and consider hospital admission if symptoms persist.

Key Reference

Cragg, J., & Krassioukov, A. (2012). Autonomic dysreflexia. Journal of Canadian Medical Association (CMAJ)8(2), 16–19. http://doi.org/10.1503/cmaj.110859

Actionable Nuggets (4th ed., 2019)

Additional References (since 2016)

Biering-Sørensen, F., Biering-Sørensen, T., Liu, N., Malmqvist, L., Wecht, J. M., & Krassioukov, A. (2017). Alterations in cardiac autonomic control in spinal cord injury.Autonomic Neuroscience: Basic and Clinical, 209, 4-18. doi:10.1016/j.autneu.2017.02.004

Dance, D. L., Chopra, A., Campbell, K., Ditor, D. S., Hassouna, M., & Craven, B. C. (2017). Exploring daily blood pressure fluctuations and cardiovascular risk among individuals with motor complete spinal cord injury: A pilot study.The Journal of Spinal Cord Medicine, 40(4), 405-414. doi:10.1080/10790268.2016.1236161

Lee, E. S., & Joo, M. C. (2017). Prevalence of autonomic dysreflexia in patients with spinal cord injury above T6.BioMed Research International, 2017, 2027594-6. doi:10.1155/2017/2027594