SCI Fact Sheet, What is Dysreflexia

Spinal Cord Injury Network

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WHAT IS 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.

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.

How do I recognize Autonomic Dysreflexia? The symptoms of AD are fairly easy to recognize and surprisingly consistent.
They include:
Sudden, pounding headaches
Flushed or blotchy skin
Facial flush, perspiration (above the level of injury) goosebumps, spasticity
A "stuffy nose"
Slow heartrate (reflex bradycardia)
and occasionally, dizziness and nausea

If any of these symptoms occur, pay attention! Start looking for the cause of AD and stop whatever is causing it!

Common sources of Autonomic Dysreflexia Sources of AD are things that irritate or stimulate the body. Common sources are:
A full or distended bladder (this is the most common source of AD)
Bladder related causes such as bladder infection, spasms, or stones
A full or impacted rectum (including constipation)
Pressure sores
Tight clothing, irritating wrinkles or folds, or creeping underwear or pants (a "wedgie")
An injury below the spinal cord injury such as a broken ankle, cut or scrape
Anything that produces discomfort below the level of injury.

Women may also experience AD during menstruation and especially during labor. For this reason, consulting a physician experienced with SCI and pregnancy is important, especially in anticipation of labor. Breast feeding and ovarian cysts have also been known to cause AD.

What to do...

The first thing to do when you recognize AD is to raise the head above the knees (preferably in a sitting position. This position naturally reduces the blood pressure. Of course, if you experience AD when you are already sitting, this is not an option. The next actions should be to remove the irritating stimulus.

Make sure your bladder is empty. Catheterize yourself or check to make sure the drainage hose to your legbag is not blocked. Note that catheterizing yourself may make the AD worse, so be careful. In extreme situations, you may have to use a lubricant with anesthetic in it.

Make sure your bowel is not full or impacted. Use your regular program routine. Again, performing your routine may make the AD worse.

Check your clothing to make sure nothing is irritating your body. Check for tight waistbands or straps, wrinkles, pinching seams, or tight shoes. Make sure your toes are not bent under in your shoes.

Check for ingrown toenails. If you find one, see a doctor!

Check your body for pressure sores (you should be doing this routinely, already), cuts, or bruises. Don't forget the possibility of a broken bone, especially if you have taken a fall. Get off the sore or take care of the problem.

Other causes of AD are less common but harder to detect. These include internal catastrophes such as appendicitis. If the cause of the AD cannot be determined quickly, seek emergency medical help.

If you think you may be at risk for AD, discuss it with a qualified physician, urologist or physiatrist, or rehab nurse. Have a plan for dealing with AD.

NSCIA, 3/96

The Factsheet is provided as an information service to you and is not intended to be replace a physicians advice. We thank Dr. Greg Nemunaitis of the Medical College of Ohio for assistance in creating this factsheet. Information you may have to update this Factsheet is greatly appreciated. The NSCIA Resource Center (NSCIRC) provides information and referral on any subject related to spinal cord injury. Contact the resource center at 1-800-962-9629.

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