Autonomic dysreflexia (AD), or hyperreflexia, is your body over reacting to something happening to it below the level of your spinal cord injury or SCI.

AD is most common in high injuries, T6 or above, and during the first few months of your SCI. It is rare and less severe, but it can happen to people with SCI’s as low as T10. AD is more common and severe in people with complete SCI’s than those with incomplete SCI’s. AD can be life threatening and is considered medical emergency.

Your autonomic nervous system is the part of your nervous system that controls parts of your body without you thinking about them, such as heart rate, circulation, breathing, digestion, sweating, etc.

Your autonomic nervous system is grouped into sympathetic and parasympathetic. Your sympathetic nervous system responds in fight or flight situations. It makes your heart beat faster, your skin’s blood vessels narrow, and widens your pupils so you can see better. Your parasympathetic nervous system responds in rest and digest situations. It makes you salivate and your skin’s blood vessels widen.

When something irritates your body below your SCI, signals are sent to your spinal cord and trigger a sympathetic (fight or flight) response. This response narrows your skin’s blood vessels and raises your blood pressure. Your blood pressure will continue to rise until what is irritating your body is stopped. When the irritant’s signal travels up your spinal cord to tell your brain what it wrong, the signal is blocked by your SCI. Sensors near your heart sense your raised blood pressure and tell your brain that there is a sympathetic response. Your brain does not know why there is a sympathetic response so it sends a parasympathetic (rest and digest) response down your spinal cord to counteract the sympathetic response. The parasympathetic signal from your brain is blocked by your SCI. This means above the level of your SCI your body shows parasympathetic symptoms and below the level of your SCI your body shows sympathetic symptoms.

The most common symptom is a sudden pounding headache caused by your raised blood pressure. The strong parasympathetic (rest and digest) response causes you to have a slow pulse, stuffed nose, small pupils, and, above the level of your SCI, flushed or splotchy and sweaty skin. The small pupils and high blood pressure can cause vision changes such as blurring, seeing spots, and narrowing of vision. Below the level of your SCI the strong sympathetic (fight or flight) response causes your skin to be pale, cool, and goose bumps covered. Because of the discomfort you may also feel nausea and/or restlessness. If left untreated autonomic dysreflexia may lead to seizures, stroke, or death.

AD requires quick action. It is important to lower your blood pressure, so first sit up straight and if possible dangle your legs. Remove or loosen any tight clothing or accessories. Have someone check your blood pressure every 2–3 minutes. Remember that the resting blood pressure for people with SCI’s is lower than it was before the SCI. It is important to take your blood pressure regularly so you know your resting blood pressure.

The most important step when you have AD is to find the cause and relieve it.

Bladder problems are the most common cause of AD. If you use intermittent catheterization, you should drain your bladder carefully with a straight catheter. If you use an indwelling catheter check to see if there is a kink or clog in the catheter or the catheter bag is full. Other bladder problems that can cause AD are urinary tract infections and bladder or kidney stones.

Bowel problems are another common cause of AD. If your stools are hard they can become stuck in your bowels and cause AD. Hard stools can be caused by a low-fiber diet or not drinking enough fluids. This can be solved by eating more high-fiber foods and drinking enough fluid. If you commonly have hard stools, you may be prescribed stool softeners. Unlubricated digital stimulation can cause can cause AD. You may need to use a prescription anesthetic lubricant to prevent this. Other bowel problems that can cause AD are excessive gas, hemorrhoids, or anal infection.

Skin problems can cause AD so it is important to check your body for cuts, bruises, abrasions, burns, frostbite, pressure sores, and ingrown toenails. Burns include sunburns and hot water burns, so it is important to wear sunscreen and check the temperature of water.

Other internal pains that can cause AD are bone fractures, over stimulation during sexual activity, menstrual cramps, labor, delivery, gastric ulcers, colitis, appendicitis, and peritonitis.

Taking precautions can lower your risk for having AD. Keeping your catheter clean and following a catheterization schedule can prevent infections and unexpected bladder problems. Eating high-fiber foods, drinking enough fluids, and following a bowel program will help keep your bowel movements on schedule and prevent bowel problems. Frequent pressure releases in your wheelchair and bed helps prevent pressure sores. Routinely check your skin so you know if you have cuts, pressure sores, or abrasions that need treatment. Using sunscreen when you are outdoors and checking water temperature can prevent burns. Dressing appropriately in cold temperatures can prevent frostbite. If AD is a frequent problem, you may be prescribed medication to manage the symptoms.

If you are unable to find the problem or relieve it within 5–10 minutes, call 911 for medical assistance.

Become familiar with the symptoms, treatments, and causes and make sure those close to you are aware as well. Since not all physicians are familiar with AD it is useful to carry a card about AD in your wallet.