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What is Autonomic Dysreflexia?

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Reeve-Foundation-logoAutonomic Dysreflexia

Autonomic dysreflexia (AD) is a potentially life-threatening medical emergency that affects people with spinal cord injuries at the T6 level or higher. Although rare, some people with T7 and T8 injuries can develop AD. For most people, AD can be easily treated as well as prevented. The key is knowing your baseline blood pressure, triggers and symptoms.

Autonomic dysreflexia requires quick and correct action. AD can lead to stroke. Because many health professionals are not familiar with this condition, it is important for people who are at risk for AD, including the people close to them, to know all about it. It is important for at-risk people to know their baseline blood pressure values and to be able to communicate to healthcare providers how to identify potential causes as well as manage an AD emergency.

Some of the signs of AD include high blood pressure, pounding headache, flushed face, sweating above the level of injury, goose flesh below the level of injury, nasal stuffiness, nausea and a slow pulse (slower than 60 beats per minute). Symptoms vary by individual; learn yours.

What to do

If AD is suspected, the first thing to do is sit up or raise the head to 90 degrees. If you can lower your legs, do so. Next, loosen or remove anything tight. Check blood pressure every five minutes. An individual with SCI above T6 often has a normal systolic blood pressure in the 90–110 mm Hg range. A blood pressure reading of 20 mm to 40mm Hg above baseline in adults may be a sign of autonomic dysreflexia, or 15mm above baseline in children, and 15mm to 20mm above baseline in adolescents. Most importantly, locate and remove the offending stimulus, if possible. Begin by looking for your most common causes: bladder, bowel, tight clothing, skin issues. Keep in mind as you remove the cause that your AD may get worse before it gets better.

Autonomic dysreflexia is caused by an irritant below the level of injury, usually related to bladder (irritation of the bladder wall, urinary tract infection, blocked catheter or overfilled collection bag) or bowel (distended or irritated bowel, constipation or impaction, hemorrhoids or anal infections). Other causes include skin infection or irritation,cuts, bruises, abrasions or pressure sores (decubitus ulcers), ingrown toenails, burns (including sunburn and burns from hot water) and tight or restrictive clothing.

AD can also be triggered by sexual activity, menstrual cramps, labor and delivery, ovarian cysts, abdominal conditions (gastric ulcer, colitis, peritonitis) or bone fractures.

What happens during an episode of AD?

Autonomic dysreflexia indicates 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 and digestion. A noxious stimulus (would be painful if one could sense it) below the injury level sends nerve impulses to the spinal cord; they travel upward until blocked at the level of injury. Since these impulses cannot reach the brain, the body doesn’t respond as it would normally. A reflex is activated that increases activity of the sympathetic portion of the autonomic nervous system. This results in a narrowing of the blood vessels, which causes a rise in 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, since the brain is not able to send messages below the level of injury, blood pressure cannot be regulated. The body is confused and can’t sort out the situation.

Generally speaking, medications are used only if the offending stimulus cannot be identified and removed, or when an episode of AD persists even after the suspected cause has been removed. A potentially useful agent is nitroglycerine paste (applied topically above level of injury). Nifedipine and nitrates are commonly used, in immediate-release form. Hydralazine, mecamylamine, diazoxide, and phenoxybenzamine might also be used. If an erectile dysfunction drug (e.g. Cialis, Viagra) has been used within 24 hours, other medications should be considered as blood pressure could drop dangerously low.

For the most part, autonomic dysreflexia can be prevented. Keep catheters clean; adhere to your catheterization and bowel schedules.

Request a free Autonomic dysreflexia Wallet card here.

Contact a Reeve Foundation Paralysis Resource Center Information Specialist
Call toll free 1-800-539-7309
(Monday through Friday 9 a.m. to 5 p.m. Eastern Time)
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or request a call back using our online form at

This article is by the Christopher & Dana Reeve Foundation Paralysis Resource Center (PRC). The PRC is a national resource which provides a road map of complimentary services and programs to empower individuals living with paralysis.

SOURCE Christopher & Dana Reeve Foundation Paralysis Resource Center

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