Autonomic dysreflexia (AD), also known as autonomic hyperreflexia, commonly effects people with spinal cord injuries at the T6 level or above, but it has been reported in people with lower thoracic lesions. It has been cited in the literature that AD affects anywhere from 48% to 90% of people with quadriplegia and high paraplegia. In a study by Braddom and Rocco, they found that only 18% of people with spinal cord injuries suffer from AD. They attributed this lower number to improved awareness and heightened attention to prevention that caused the reduction in the number of occurrences.

The classic symptoms of AD are: hypertension, sweating, headache, and bradycardia (rapid heart rate). Other symptoms include: pilomotor erection, pallor below and flushing above the lesion level, shortness of breath, and associated anxiety. Severity can range from excessive sweating to life-threatening high blood pressure. Blood pressures may be as high as 190 - 250 mm Hg systolic and 130 - 150 mm Hg diastolic. Common causes of AD are an obstructed urinary catheter with distended bladder, pressure sores, and rectal impaction. Some uncommon causes are ingrown toenails, fractures, gallbladder disease, body position, pregnancy, labor and delivery, deep vein thrombosis, passive range of motion, and tight clothing.

The best treatment is to identify the noxious stimulant and to remove it. If removal of the stimulus does not alleviate the symptoms, then medical attention may be necessary, especially with elevated blood pressure. Medication may be necessary to either prevent AD, or to alleviate the symptoms once an episode occurs.