Autonomic dysreflexia (hyperreflexia), a spinal cord injury complication, may cause sudden high blood pressure

Autonomic dysreflexia (hyperreflexia)Autonomic dysreflexia (hyperreflexia), a spinal cord injury complication, may cause sudden high blood pressure. Autonomic dysreflexia is a condition in which the involuntary nervous system overreacts to external and bodily stimuli, causing a spike in blood pressure, rapid heart rate, constriction of peripheral blood vessels, and other changes to bodily functions.

Autonomic dysreflexia is commonly seen in individuals with spinal cord injuries that occur above the sixth thoracic vertebra (T6). Autonomic dysreflexia is commonly seen in multiple sclerosis patients, Guillain-Barre syndrome, and some head or brain injuries. It can also be caused by certain medications.


In some incidences, autonomic dysreflexia can be life-threatening, as it can lead to stroke, retinal hemorrhage, cardiac arrest, and pulmonary edema.

When blood pressure rises to dangerous levels in autonomic dysreflexia, this is what can contribute to life-threatening conditions.

Autonomic dysreflexia causes, symptoms, and signs

Autonomic dysreflexia is caused by irritating stimuli to the injury site. The autonomic nervous system (ANS) is responsible for many bodily functions, including blood pressure, body temperature, heart rate, digestion, metabolism, production of bodily fluids, urination, defecation, and sexual response. When autonomic dysreflexia occurs, many of these bodily functions can become disturbed.

Other causes of autonomic dysreflexia include:

  • Guillain-Barre syndrome
  • Medication side effects
  • Severe head trauma and other brain injuries
  • Subarachnoid hemorrhage (a form of brain bleeding)
  • Use of illegal stimulant drugs such as cocaine and amphetamines

Signs and symptoms of autonomic dysreflexia include:

  • Anxiety
  • Irregular or racing heart beat
  • Nasal congestion
  • High blood pressure
  • Pounding headache
  • Flushing of skin
  • Profuse sweating
  • Lightheadedness
  • Dizziness
  • Confusion
  • Dilated pupils

Other conditions share symptoms of autonomic dysreflexia, but have different causes, including carcinoid syndrome, neuroleptic malignant syndrome, pheochromocytoma, serotonin syndrome, and thyroid storm.

Autonomic dysreflexia treatment and prevention

The initial goal of autonomic dysreflexia treatment is to reduce blood pressure in order to prevent complications related to hypertension, including death. Some methods to treat blood pressure are:

  • Being in a seated position, so blood can move to the feet
  • Removing tight clothing and socks
  • Checking for a blocked catheter
  • Draining a distended bladder with a catheter
  • Treatment for fecal impaction
  • Administering vasodilators and other medications to lower blood pressure


If medications are the cause for autonomic dysreflexia, then your doctor will advise to stop the medication in question. Lastly, if a slow heart rate is causing symptoms, it is treated with anticholinergics.

Prevention methods rely on targeting underlying causes for autonomic dysreflexia. Some prevention methods include:

  • Change medication or diet
  • Manage urinary catheters
  • Take medications for blood pressure
  • Use medications or a pacemaker to regulate heart rate
  • Exercise self-management to avoid personal triggers

Proper management and prevention of autonomic dysreflexia is essential, as it can become a life-threatening condition, so speak with your doctor about any concerns about your condition.


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