Autonomic dysreflexia

Autonomic dysreflexia is a sudden and exaggerated autonomic response to an unpleasant/noxious stimulus.

Examples of unpleasant stimuli include:

• A full rectum
• Digital stimulation of the rectum during a bowel evacuation
• A blocked catheter or anything that would have been painful, uncomfortable or physically irritating to the individual before the injury
• Stimuli could also include a fracture, appendicitis, sexual intercourse, period pain, pregnancy

Autonomic dysreflexia is a potentially life threatening condition that occurs in individuals with spinal cord injury at level T6 and above. Individuals with spinal injuries T6 to T10 are also susceptible to autonomic dysreflexia.

An episode of autonomic dystreflexia

What happens? The person rapidly develops elevated blood pressure and bradycardia.

The sensory nerves are intact below the injury level and when excited by the noxious stimuli there is a sudden relatively unopposed sympathetic outflow, which suddenly elevates the blood pressure.

Parasympathetic outflow through the vagus nerve causes the pulse to slow down. This is known as reflexive bradycardia but cannot compensate for the severe vasoconstriction.

Common signs and symptoms

Common signs and symptoms are:

• Bradycardia
• Pounding headache
• Hypertension
• Skin flushing above the level of the injury
• Sweating above the level of the injury
• Goosebumps above the level of the injury
• Nasal congestion
• Bronchospasm
• Blurred vision
• Chills without fever
• Apprehension and anxiety

Treatment

• Look for the noxious stimuli below the level of the spinal injury – relieve if possible – it is often related to bowel function
• If possible sit individual up and elevate the head
• Give prescribed antihypertensive medication
• Give reassurance

Further information about autonomic dysreflexia is available from the Caring for Persons with Spinal Cord Injury website^[1].

Reference

_{1. Autonomic dysreflexia. Caring for Persons with Spinal Cord Injury. [Updated 22 September 2012; cited 24 August 2018]. Available from: http://eprimarycare.onf.org/AutonomicDysreflexia.html}