What is Autonomic Dysreflexia?

Autonomic dysreflexia is a potentially life-threatening syndrome which occurs in patients with spinal cord injuries or lesions caused by diseases like multiple sclerosis. The injury is usually above the level of the fifth thoracic vertebrae. People can experience autonomic dysreflexia at any point after a spinal cord injury, although it is most common in the first year after injury. Because of the risk, some people carry a medical alert card explaining the syndrome and providing basic instructions about what to do so that in the event that they experience autonomic dysreflexia, they can hand the card to someone who can help.

The syndrome starts with a stimulus below the level of the injury, usually a noxious stimulus. One of the most common causes is an overfull or infected bladder, but other stimuli can include signals from the bowels, or signals sent as a result of a cut, burn, or broken bone. The signals travel up the spinal cord, but cannot reach the brain because of the injury, and the autonomic nervous system goes into overdrive as a result.

The blood vessels narrow and spasms may occur. The brain attempts to regulate blood pressure by slowing the heartbeat and widening the blood vessels, but it cannot accomplish regulation because of the lack of control over areas of the body below the injury. The patient usually becomes clammy and cold, can feel dizzy and nauseous, and may have blurred vision. Strokes and seizures can occur as a result of autonomic dysreflexia.

Also known as hyperreflexia, autonomic dysreflexia needs to be treated immediately. The patient's head should be kept elevated, either by sitting upright or raising the head of the bed, and the cause should be identified and corrected, if possible. For example, if the problem is an overfilled bladder, the bladder should be catheterized to drain the urine. The cause may require medical treatment, as in the case of a broken bone, in which case the patient should be kept as stable as possible and taken to the hospital for treatment.

If someone starts to identify the early signs of autonomic dysreflexia, he or she should speak up. This is especially important if the syndrome is being triggered by something a care provider is doing. Rapid intervention to stop the dysregulation of the blood pressure before it goes too far is important to prevent permanent damage and to get the patient out of danger.