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.

AD requires quick and correct action. Serious AD can lead to a stroke. Because many health professionals are not familiar with this condition it is important for people who are at risk for AD, and the people close to them, to learn about it.

What to do

The first thing to do if AD is suspected is to sit up, or raise your head to 90 degrees. If you can lower your legs, do so. Next, loosen or remove anything tight. Most importantly, locate and remove the offending stimulus, if possible.

The signs of AD include:

    * High blood pressure (greater than 200/100)        
    * Pounding headache, flushed face        
    * Sweating above level of spinal injury        
    * Nasal stuffiness, nausea        
    * Slow pulse, lower than 60 beats per minute        
    * Goose flesh below level of spinal injury

AD is caused by an irritant below the level of injury, usually related to bladder or bowel function. Among the causes are:

    * Irritation of bladder wall, urinary tract infection        
    * Blocked catheter        
    * Overfilled collection bag        
    * Over-distended or irritated bowel
    *Constipation/impaction        

    * Hemorrhoids or anal infections        
    * Skin infection or irritation, cuts, bruises, abrasions        
    * Pressure sores (decubitus ulcer)        
    * Ingrown toenails        
    * Burns (including sunburn, burns from using hot water)        
    * Tight or restrictive clothing        
    * Sexual activity        
    * Menstrual cramps        
    * Labor and delivery        
    * Abdominal conditions (gastric ulcer, colitis, peritonitis)        
    * Bone fractures

AD can be prevented:

    * Relieve pressure in bed/chair -- frequently        
    * Use #15 sunscreen, watch water temperatures        
    * Adhere to bowel program, faithfully        
    * Keep catheters clean and stick to catheterization schedule

What happens during a episode of AD?

Autonomic dysreflexia means an over-activity of the autonomic nervous system – the part of the system that controls things you don’t have to think about, such as heart rate, breathing, digestion, etc. AD can occur when an irritating stimulus is introduced to the body below the level of injury. The stimulus sends nerve impulses to the spinal cord, where they travel upward until they are blocked at the level of injury.

Since the impulses cannot reach the brain, a reflex is activated that increases activity of the sympathetic portion of autonomic nervous system. This results in spasms and a narrowing of the blood vessels, which causes a rise in the blood pressure. Nerve receptors in the heart and blood vessels detect this rise in blood pressure and send a message to the brain.

The brain then sends a message to the heart, causing the heartbeat to slow down and the blood vessels above the level of injury to dilate. However, the brain cannot send messages below the level of injury, due to the spinal cord lesion, and therefore the blood pressure cannot be regulated.

Medications are generally used only if the offending trigger/stimulus cannot be identified and removed - or when an episode persists even after removal of the suspected cause. Potentially useful agents include: Nitroglycerine, Clonidine, Hydralazine, Minipress, Catapres.

Sources: Paralyzed Veterans of America, Spinal Injuries Association, London, National Spinal Cord Injury Association, Miami Project to Cure Paralysis/University of Miami School of Medicine