What health care professionals should know about Autonomic dysreflexia

This is a summary of the article written by Sara Morgan, ”Management of autonomic dysreflexia in the community.” published in British Journal of Community Nursing 2020.

Autonomic Dysreflexia

Autonomic dysreflexia (AD) is an episodic uncontrolled elevation of systolic blood pressure sometimes accompanied by bradycardia. If not managed it can lead to cerebral and spinal hemorrhage, seizures and pulmonary edema.

AD is a condition affecting spinal cord injured persons with an injury at or above the level of the 6th thoracic vertebrae (T6). It is a poorly understood condition affecting many persons. According to World Health Organization (2013) an estimate of a quarter to half a million persons sustain a spinal cord injury every year. Of those, up to 90% with injuries at or above T6 may be affected by AD.

When a spinal cord injury occurs, all autonomic nerve function below the injury stops. The autonomic nervous system maintains the homeostasis and regulates cardiac and smooth muscle activity as well as endocrine secretions. It is divided into two branches: the sympathetic and the parasympathetic nervous systems.

The sympathetic is stimulated to deal with stressful situations while the parasympathetic activation slow down cardiac and respiratory activity. These two branches function together to maintain a physiological balance of heart rate, blood pressure and respiration rate.

What triggers an AD episode?

The disruption of the autonomic nervous system when a spinal cord injury occurs is the cause of AD. Noxious stimuli below the level of injury can cause a sympathetic response resulting in vasoconstriction while inhibitory signals from the brain are not received. As a result of the peripheral and splanchnic vasoconstriction, hypertension is seen, which is a classic sign of AD.

The rapid rise in blood pressure can lead to an increase in intracranial pressure, causing seizures and intracranial hemorrhage. The level of the injury affects the severity; the higher the level of the injury, the more intense the effects on circulation and thermoregulation.

AD most often presents 3-6 months after the spinal cord injury. Persons at risk of AD have various support needs for independence as well as issues with bladder and bowel management.

Symptoms of AD

In most cases, the persons at risk of AD has some contact with healthcare and it is important that the healthcare professionals meeting them have the knowledge and understanding of AD to be able to identify and react quickly to prevent further complications. A dysreflexia crisis is an acute condition requiring immediate treatment or emergency transfer.

It is not just during an AD episode that the blood pressure can be affected by a spinal cord injury. The disruption of the sympathetic nervous system has effects on the cardiovascular system that may lead to a consistently low resting blood pressure and orthostatic hypotension.

In those cases, a resting systolic blood pressure of 90 mmHg is normal and a blood pressure of 120/80 mmHg, that is considered normal in an adult population, is elevated. It is therefore important to consider the normal blood pressure of the spinal cord injured person since AD is defined as an elevation of the systolic blood pressure of more than 20mmHg.

The main symptoms of AD are:

  • Elevated blood pressure
  • Pounding headache
  • Bradycardia
  • Profuse sweating above the level of injury
  • Goose bumps above or possibly below the level on injury
  • Cardiac arrhythmias
  • Flushing of the skin
  • Blurred vision
  • Nasal congestion

Most of the symptoms are thought to be caused by the activation of the sympathetic nervous system. Exceptions are head and neck flushing, sweating and nasal congestion that most likely are caused by the parasympathetic response of baroreceptor activation.

How should AD be managed?

AD is an acute medical condition that requires rapid patient assessment to be safely managed. An assessment tool that can be used within the community to assess rapidly deteriorating patients is ABCDE.

Airway - airway compromise is unlikely to be presented in a dysreflexic crisis, but there may be untreated airway problems that can lead to hypoxia and eventually cardiac arrest if untreated. Simple airway maneuvers such as head tilt or chin lift are enough.

Breathing – check the rate, rhythm and depth of respiration as well as oxygen saturations. To be noted, a high spinal cord injury may alter the breathing pattern per se.

Circulation – this is the most commonly identified symptom of an AD crisis. Hypertension and reflex bradycardia are common symptoms together with complaints of pounding headache, neck and head flushing as well as blurred vision.

Disability – tools such as Alert, Voice, Pain, Unresponsive can be used to assess the responsiveness of the person affected by AD.

Exposure – the final stage in assessment may identify the noxious stimulus causing the AD. A head-to-toe examination should be undertaken, and body temperature checked. For example, a distended abdomen may indicate constipation. The need of bladder or bowel emptying, pressure ulcers or ingrowing toenails can cause the stimuli triggering an AD episode.

Early detection and treatment are important to avoid complications and hospital admission. AD may require both non-pharmacological and pharmacological interventions; non-pharmacological treatment is considered first line treatment in persons who are not displaying severe hypertension. Often is removal of the stimuli enough to eliminate the AD response.

Therefore, identifying and removing the noxious stimuli should be a priority. The person should be asked about their bowel care and when the bowels were last emptied. If necessary, bowel care should be administered. In many cases, draining the bladder may resolve the AD crisis.

Other recommendations include sitting the person up, remove tight or restrictive clothing, inspect the skin for pressure ulcers and lacerations, and check for ingrowing toenails. If blood pressure continues to rise, pharmacological management may be required.

It is recommended that persons with recurrent AD crisis have an emergency treatment box to treat their AD symptoms pharmacologically at home.

Education in bladder and bowel management is important as well as information about AD to enable self-management techniques once symptoms appears. Education is a vital component of long-term management of this condition.

In summary, AD is a result of a noxious stimuli causing a raise of at least 20 mmHg of the systolic blood pressure in persons with a spinal cord injury at or above T6. Non-pharmacological intervention could be to remove the noxious stimuli such as bladder distension and bowel emptying.


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