Tuesday, July 16, 2024
HomeInformationAutonomic Dysreflexia

Autonomic Dysreflexia

| Source: spinalcord.org

Autonomic Dysreflexia (AD), also known as Hyperreflexia, is a potentially dangerous complication of spinal cord injury (SCI). In AD, an individual’s blood pressure may rise to dangerous levels and if not treated can lead to stroke and possibly death. Individuals with SCI at the T-6 level or above are at greater risk. AD usually occurs because of a noxious (irritating) stimulus below the level of the injury. Symptoms include headache, facial flush, perspiration, and a stuffy nose.

AD occurs primarily because of an imbalance in the body systems which control the blood pressure. The human body is an incredibly complicated and beautifully balanced machine. There are balances to each system of the body, including the blood pressure. One of the major ways the body controls blood pressure is by tightening or relaxing little muscles around the blood vessels. When the muscles contract, the blood vessels get smaller and blood pressure increases. Imagine a garden hose with water streaming through it; when you put your thumb over the opening of the hose, reducing the opening for the water to flow through, the water shoots out at a higher pressure. Similarly, when the blood vessels are smaller, the blood rushes around your body at higher pressure.

When a noxious stimulus occurs, a Reflex is initiated that causes the blood vessels to constrict and raises the blood pressure. In an intact spinal cord, this same stimulus also sets in motion another set of reflexes that moderates the constriction of blood vessels. However, in someone who has SCI at the T-6 level or above, the signal which tells the blood vessels to relax cannot get through the spinal cord because of the injury. Some of the nerves at the T-6 level also control the blood flow to and from the gut, which is a large reservoir of blood. Uncontrolled activity of these nerves may cause the blood from the gut to flow into the rest of the blood system. The result is that blood pressure can increase to dangerous levels and the increase in blood pressure must be controlled by outside means.

Autonomic Dysreflexia (AD), in the simplist terms, is the nervous system going crazy. Individuals that have a T-5, or higher, injury are the ones generally subject to suffering from AD. This is a condition that can be life-threatening and can be considered a medical emergency .

What are the indicators for the onset of AD?

  • Hypertension (blood pressure greater than 200/100)
  • Pounding headache
  • Flushed (reddened) face
  • Red blotches on the skin above level of spinal injury
  • Sweating above level of spinal injury
  • Nasal stuffiness
  • Nausea (secondary to vagal parasympathetic stimulation)
  • Bradycardia – slow pulse <60 beats per minute
  • Piloerection (“goose bumps”) below level of spinal injury
  • Cold, clammy skin below level of spinal injury

Irritants, things which would ordinarily cause pain, to areas of body below the level of spinal injury.

Things to consider include:

Bladder (most common) – from overstretch or irritation of bladder wall

  • Urinary Tract Infection (UTI)
  • Urinary retention
  • Blocked Catheter
  • Overfilled collection bag
  • Non-compliance with Intermittent Catheterization program


  • overdistention or irritation
  • Constipation / impaction
  • Distention during Bowel program (digital stimulation)
  • Hemorrhoids or anal infections
  • Infection or irritation

Skin-related Disorders

  • Any direct irritant below the level of injury
  • Pressure by object in shoe or chair, cut, bruise, abrasion
  • Pressure sores (Decubitus Ulcer)
  • Ingrown toenails
  • Burns (eg. – sunburn, burns from using hot water)
  • Tight or restrictive clothing or pressure to skin from sitting

Sexual Activity

  • Overstimulation during sexual activity
  • [stimuli to the pelvic region which would ordinarily be painful if sensation were present]
  • Menstrual cramps
  • Labor and delivery

Other Causes

  • Heterotopic Ossification (“Myositis ossificans”, “Heterotopic bone”)
  • Acute abdominal conditions (gastric ulcer, colitis, peritonitis)
  • Skeletal fractures

The first thing to do is locate and remove the offending stimulus whenever possible. This will often prove successful enough to avoid pharmacological intervention. Once the source of irritation has been removed it will be a good idea to have the individual remain in a sitting up position and take frequent blood pressure checks until the episode has ended.

Typical Causes

Blocked Catheter
The most common cause of AD is a catheter that has become blocked. You will want to check the collection bag, irrigate the catheter and remove any kinks.

If symptoms begin while digital stimulation is being performed, stop until symptoms quit. If the individual has impacted stool – begin disimpaction immediately. If digital stimulation continues to bring on the symptoms you may want to consider abdominal massage or commode-based bowel evacuation methods

Skin irritation, also a common cause of AD, is most often stopped by loosening the clothing. You will was to check for pressure sores and toenail problems.

How can Autonomic Dysreflexia be prevented?

  • Frequent pressure relief in bed/chair
  • Avoidance of sun burn/scalds (avoid overexposure, use of #15 sunscreen, watch water temperatures)
  • Faithful adherence to Bowel program
  • Keep catheters clean and remain faithful to catheterization schedule
  • Well balanced diet and adequate fluid intake Compliance with medications

This site uses Akismet to reduce spam. Learn how your comment data is processed.

- Advertisment -

Must Read

Study identifies drug target to prevent autonomic dysfunction after spinal cord...

In response to stressful or dangerous stimuli, nerve cells in the spinal cord activate involuntary, autonomic reflexes often referred to as "fight or flight"...