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Autonomic Dysreflexia

Thomas Cody, MD
Staff Physiatrist - Northeast Rehabilitation Hospital

Veronica (Roni) Zieroff, RN, BS, CRRN
Spinal Cord Injury Program Team Leader - Northeast Rehabilitation Hospital

What is "Autonomic Dysreflexia?"

Autonomic dysreflexia is a syndrome characterized by abrupt onset of excessively high blood pressure caused by uncontrolled sympathetic nervous system discharge in persons with spinal cord injury. Persons at risk for this problem generally have injury levels above T-6. True autonomic dysreflexia is potentially life-threatening and is considered a medical emergency.

What are signs and symptoms of Autonomic Dysreflexia?

• Hypertension (blood pressure greater than 200/100)

• Pounding headache (secondary to hypertension/vasodilatation)

• Flushed (reddened) face (secondary to vasodilatation)

• Red blotches on the skin above level of spinal injury (secondary to vasodilatation)

• Sweating above level of spinal injury (secondary to vasodilatation)

• Nasal stuffiness (secondary to vasodilatation)

• Nausea (secondary to vagal parasympathetic stimulation)

• Bradycardia - slow pulse <60 beats per minute - (secondary to vagal parasympathetic stimulation)

• Piloerection ("goose bumps") below level of spinal injury

• Cold, clammy skin below level of spinal injury

What sort of things can precipitate this syndrome?

In general, noxious stimuli (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
  • Urinary retention
  • Blocked catheter
  • Overfilled collection bag
  • Non-compliance with intermittent catheterization program
• Bowel - over distention or irritation
  • Constipation / impaction
  • Distention during bowel program (digital stimulation)
  • Hemorrhoids or anal fissures
  • Infection or irritation (eg. appendicitis)

• Skin-related Disorders
  • Any direct irritant below the level of injury (eg. - prolonged 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 on wrinkled clothing
• Sexual Activity
  • Over stimulation during sexual activity [stimuli to the pelvic region which would ordinarily be painful if sensation were present]
  • Menstrual cramps

• Labor and delivery

• Other
  • Heterotopic ossification ("Myositis ossificans", "Heterotopic bone")
  • Acute abdominal conditions (gastric ulcer, colitis, peritonitis)
  • Skeletal fractures

What can be done to manage an episode of autonomic dysreflexia?

Principle #1 is to identify and remove the offending stimulus whenever possible. Often, this alone is successful in allowing the syndrome to subside without need for pharmacological intervention. It is also good for the person with the symptoms to be sitting up with frequent blood pressure checks until the episode has resolved. [In hospital-based settings or in high-risk individuals / persons who have recurrent episodes, consideration should be given having atropine at the bedside]

Suspected cause = bladder? Check catheter - remove kinks if found, empty urinary collection bag, irrigate catheter. If catheter is not draining, replace it immediately. If an intermittent catheterization program is in place, a straight catheterization should be performed immediately with (slow drainage to prevent bladder spasms).

Suspected cause = bowel? If episode happens during digital stimulation, stop stimulation until symptoms and signs subside. Consider use of a prescribed anesthetic ointment to suppress the noxious stimulus. If the issue is impacted stool, disimpact. If it occurs while doing a bowel program in bed, try commode-based bowel evacuation. Consider use of abdominal massage instead of digital stimulation.

Suspected cause = skin? Loosen clothing. Check for source of potential offending stimulus - check for pressure sores, toenail problems, soles of the feet.

If symptoms persist despite interventions such as the foregoing, notify a physician.

What medical interventions are possible when removal of noxious stimuli doesn't end an episode of autonomic dysreflexia?

Medications are generally used only if the offending trigger/stimulus cannot be identified and removed - or when an episode persists even after removal of the suspected cause. Potentially useful agents include:

• Immediate/emergent
  • Nitroglycerine - 1/150 sublingual or 1/2 inch Nitropaste topically
  • Clonidine - 0.1 to 0.2 mg. p.o.
  • Hydralazine - 10 to 20 mg. IM/IV

• Chronic (recurrent episode prevention)
  • Prazosin ("Minipress") - 0.5 to 1.0 mg. daily
  • Clonidine ("Catapres") - 0.2 mg. p.o. b.i.d.

How can autonomic dysreflexia be prevented?

• Frequent pressure relief in bed/chair
• Avoidance of sun burn/scalds (avoid overexposure, use of #15 or greater sunscreen, watch water temperatures)
• Faithful adherence to bowel program (no longer than 3 days between bowel evacuations)
• Keep catheters clean and remain faithful to intermittent catheterization schedule
• Well balanced diet and adequate fluid intake
• Compliance with medications
• Persons at risk and those close to them should be educated in the causes, signs and symptoms, first aid, and prevention of autonomic dysreflexia.