Spinal cord injury patient having their blood pressure monitored

Autonomic Dysreflexia Explained

Spinal cord injuries of all types present significant challenges to the individual. Not only could there be loss of sensation or reduced mobility as a result of the injury, but there are likely to be a variety of other different symptoms depending on the severity and location of the damage.

The higher up the damage on the spine, the more challenging it can be. The symptoms that patients have to deal with can include loss of bowel and bladder control, difficulty breathing and spasticity (where muscles contract rapidly). Spinal cord injuries may also have an impact on sexual function and the ability to reproduce.

One potentially dangerous symptom associated with spinal cord injuries, involving the thoracic nerves or above, is known as autonomic dysreflexia.

What is Autonomic Dysreflexia?

Autonomic dysreflexia (AD) is serious health condition that typically affects individuals who have sustained damaged to their spinal cord at the T6 level or above. These are the spinal nerves of the upper back and neck.

The reason damage to this area is so significant is because anything below that level can be affected. Autonomic dysreflexia causes a rise in blood pressure and, combined with a low heart rate, this can lead to a stroke or heart failure if something isn’t done.

Nerve signals from the brain to the spinal cord generally control voluntary things like movement. The spine also has a role to play in autonomic or involuntary processes such as maintaining blood pressure which occur in response to a ‘noxious’ stimulus.

In normal circumstances, if an individual sustained an injury, their blood pressure would increase and a message would be sent to the brain. In turn, the autonomic system will make adjustments such as slowing the heart rate and opening up the blood vessels. For SCI patients, the latter may not happen, which can increase the risk of a heart attack because the system isn’t behaving as it should.

Causes of Autonomic Dysreflexia

From the moment that damage occurs to the spine and autonomic dysreflexia is potentially a problem, it can be triggered by a number of different circumstances.

  • Problems with the bladder can initiate autonomic dysreflexia. This can come from simply having a full bladder, getting an infection in the urinary tract or a catheter that becomes blocked.
  • Equally, issues with the bowel can also lead to autonomic dysreflexia starting, including constipation, haemorrhoids or an irritable bowel.
  • Skin problems such as infections or cuts, bed sores or even ingrown toenails can raise blood pressure, leading to autonomic dysreflexia.
  • Autonomic dysreflexia can also be initiated by sexual activity, bone fractures, menstrual problems and ovarian cysts.

Autonomic Dysreflexia Symptoms

The common signs of autonomic dysreflexia include:

  • Feeling flushed and a heavy headache
  • Slow heart rate
  • Anxiety
  • Goosebumps on the lower body.
  • Stuffy or blocked nose.
  • Blurry vision

Checking blood pressure is often a way to keep track of autonomic dysreflexia, especially if the individual is worried about it occurring. The normal systolic blood pressure for an SCI patient with damage to T6 or above is between 90 and 110 mg Hg. 20 to 40 mm above this baseline may suggest that someone is going into autonomic dysreflexia (this should be 15-20 mm for children).

Treating and Managing Autonomic Dysreflexia

Treating autonomic dysreflexia

The good news, despite the seriousness of autonomic dysreflexia, is that there are things an individual can do to prevent it happening and to keep themselves comfortable while they wait for medical assistance.

  • Treatment of autonomic dysreflexia depends on recognizing the symptoms and quickly acting to improve things.
  • The individual should sit up as much as they can to get the blood moving towards the lower body and to ease blood pressure.
  • Loosening any clothing as much as possible is advised.
  • Going to the toilet can relieve pressure quickly, even if the individual doesn’t feel the need to go.

Many patients with a spinal cord injury of T6 and above will have medication that is used to drop blood pressure quickly in the event of an autonomic dysreflexia attack. A commonly used medicine is Nifedipine, which is taken in tablet form. An important thing is for the individual to try not to panic – this is something that most SCI patients eventually get used to and learn to monitor effectively.

Living with Autonomic Dysreflexia

Autonomic dysreflexia is a serious issue for some SCI patients, associated with injuries high up on the spinal cord. While it can be life-threatening, for most, it means being watchful and understanding the symptoms and is something they eventually manage to live with quite easily.