2.4. Autonomic Dysreflexia
Autonomic Dysreflexia (AD), also known as Hyperreflexia, is a potentially dangerous complication of spinal cord injury (SCI). In AD, an individual's blood pressure may rise to dangerous levels and if not treated can lead to stroke and possibly death. Individuals with SCI at the T-6 level or above are at greater risk. AD usually occurs because of a noxious (irritating) stimulus below the level of the injury. Symptoms include headache, facial flush, perspiration, and a stuffy nose.
One of the most useful resources for individuals with SCIs is our laminated, wallet-sized quick reference AD Medical Alert Card to carry in your wallet or billfold, provided courtesy of United Spinal Association in collaboration with Woodrow Wilson Rehabilitation Center (WWRC) whose staff provided the medical content. Download your own AD card right now by clicking below.
AD occurs primarily because of an imbalance in the body systems which control the blood pressure. The human body is an incredibly complicated and beautifully balanced machine. There are balances to each system of the body, including the blood pressure. One of the major ways the body controls blood pressure is by tightening or relaxing little muscles around the blood vessels.
When the muscles contract, the blood vessels get smaller and blood pressure increases. Imagine a garden hose with water streaming through it; when you put your thumb over the opening of the hose, reducing the opening for the water to flow through, the water shoots out at a higher pressure. Similarly, when the blood vessels are smaller, the blood rushes around your body at higher pressure.
When a noxious stimulus occurs, a reflex is initiated that causes the blood vessels to constrict and raises the blood pressure. In an intact spinal cord, this same stimulus also sets in motion another set of reflexes that moderates the constriction of blood vessels. However, in someone who has SCI at the T-6 level or above, the signal which tells the blood vessels to relax cannot get through the spinal cord because of the injury.
Some of the nerves at the T-6 level also control the blood flow to and from the gut, which is a large reservoir of blood. Uncontrolled activity of these nerves may cause the blood from the gut to flow into the rest of the blood system. The result is that blood pressure can increase to dangerous levels and the increase in blood pressure must be controlled by outside means.
What is "Autonomic Dysreflexia"?
Autonomic dysreflexia (AD), in the simplist terms, is the nervous system going crazy. Individuals that have a T-5, or higher, injury are the ones generally subject to suffering from AD. This is a condition that can be life-threatening and can be considered a medical emergency .
What are the indicators for the onset of AD?
- Hypertension (blood pressure greater than 200/100)
- Pounding headache
- Flushed (reddened) face
- Red blotches on the skin above level of spinal injury
- Sweating above level of spinal injury
- Nasal stuffiness
- Nausea (secondary to vagal parasympathetic stimulation)
- Bradycardia - slow pulse <60 beats per minute
- Piloerection ("goose bumps") below level of spinal injury
- Cold, clammy skin below level of spinal injury
What sort of things can precipitate this syndrome?
Irritants, things which would ordinarily cause pain, to areas of body below the level of spinal injury.
Things to consider include:
Bladder (most common) - from overstretch or irritation of bladder wall
- Urinary tract infection (UTI)
- Urinary retention
- Blocked catheter
- Overfilled collection bag
- Non-compliance with intermittent catheterization program
- overdistention or irritation
- Constipation / impaction
- Distention during bowel program (digital stimulation)
- Hemorrhoids or anal infections
- Infection or irritation
- Any direct irritant below the level of injury
- Pressure by object in shoe or chair, cut, bruise, abrasion
- Pressure sores (decubitus ulcer)
- Ingrown toenails
- Burns (eg. - sunburn, burns from using hot water)
- Tight or restrictive clothing or pressure to skin from sitting
- Overstimulation during sexual activity
- [stimuli to the pelvic region which would ordinarily be painful if sensation were present]
- Menstrual cramps
- Labor and delivery
- Heterotopic ossification ("Myositis ossificans", "Heterotopic bone")
- Acute abdominal conditions (gastric ulcer, colitis, peritonitis)
- Skeletal fractures
What can be done to manage an episode of autonomic dysreflexia?
The first thing to do is locate and remove the offending stimulus whenever possible. This will often prove successful enough to avoid pharmacological intervention. Once the source of irritation has been removed it will be a good idea to have the individual remain in a sitting up position and take frequent blood pressure checks until the episode has ended.
The most common cause of AD is a catheter that has become blocked. You will want to check the collection bag, irrigate the catheter and remove any kinks.
If symptoms begin while digital stimulation is being performed, stop until symptoms quit. If the individual has impacted stool - begin disimpaction immediately. If digital stimulation continues to bring on the symptoms you may want to consider abdominal massage or commode-based bowel evacuation methods
Skin irritation, also a common cause of AD, is most often stopped by loosening the clothing. You will was to check for pressure sores and toenail problems.
How can autonomic dysreflexia be prevented?
- Frequent pressure relief in bed/chair
- Avoidance of sun burn/scalds (avoid overexposure, use of #15 sunscreen, watch water temperatures)
- Faithful adherence to bowel program
- Keep catheters clean and remain faithful to catheterization schedule
- Well balanced diet and adequate fluid intake Compliance with medications
Other fact sheet sources:
PVA Consortium Consumer Guide on AD in Spanish language
Autonomic Dysreflexia - Information sheet published by the Model Systems Knowledge Translation Center, 2016.
Automatic Dysreflexia (Hyperreflexia) Calder Memorial Library of the University of Miami/Jackson Memorial Medical Center
The SCI Forum presentation, "Autonomic Dysreflexia," by Janna Friedly, MD, assistant professor in the Department of Rehabilitation Medicine at the University of Washington, is now available on the Northwest Regional Spinal Cord Injury System Web site for viewing on your computer as streaming video. A written report of the presentation is also online.
Paralysis Resource Center : Autonomic Dysreflexia
Autonomic dysreflexia (AD) is a potentially life threatening condition that can be considered a medical emergency. It mainly affects people with injuries at T-5 or higher.
UAB article reprint-Autonomic Dysreflexia - A Possible Life-Threatening Situation
SEE Autonomic Dysreflexia video in the VIDEO RESOURCE ROOM referenced below