Autonomic Dysreflexia

Autonomic Dysreflexia (AD) is one of the most severe injuries of the spinal cord conditions. Get detailed information about the disease, including its causes, symptoms, preventive methods and treatment options.

Autonomic Dysreflexia Definition

It is a dangerous spinal condition characterized by sudden increase in the blood pressure level due to over-activity of the ANS or Autonomic Nervous System. Individuals with injury levels more than T-6 are more likely to develop this condition. This potentially life threatening disorder can develop suddenly and is regarded as a medical emergency. It can lead to various health problems including stroke, seizures and even death if left untreated. AD can occur in children with a serious spinal cord injury.

Autonomic Dysreflexia Mechanism

Individuals with a history of severe spinal cord injury with spinal wounds above the spinal cord level T6 run a greater risk of developing this disorder. AD generally occurs due to a painful stimulus below the spinal cord injury level. The stimulus is mediated through the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

Picture 1 – Autonomic Dysreflexia

The CNS consists of the brain and the spinal cord, being responsible for controlling voluntary acts as well as end organs through their respective nerves. The PNS constitutes twelve pairs of spinal nerves, cranial nerves and peripheral nerves. The intact lower motor-neurons of individuals with high level spinal cord injury can detect the painful stimuli situated below the level of spinal cord injury and transfer the massage through the spinal cord. The signal of the pain is interrupted at the level of spinal cord injury and is prevented from being sent to the cerebral cortex of the brain. The site of injury interrupts the communication between the two branches of the autonomic nervous system (ANS) by disconnecting the feedback loop which results in independent functioning of these two branches. The ascending information stimulates sympathetic responses after reaching the major sympathetic output named splanchnic outflow (T5-T6). This sympathetic response leads to vasoconstriction, causing various symptoms of AD such as hypertension, headache and anxiety. Hypertension, resulting from the condition, stimulates the baroreceptors located in the aortic arch and carotid sinuses.

Autonomic Dysreflexia Causes

It can result from various stimuli. Anything that can cause pain, discomfort and irritation in people who do not have any spinal cord injury can cause Autonomic Hyperreflexia in those with a serious spinal injury. An overfilled bladder is believed to be the most common reason behind AD. The main causes responsible for bladder overfilling include:

  • Blockage in urinary drainage system
  • Bladder infections
  • Bladder spasms
  • Stone formation in bladder

Bowel impaction is another principal causative factor for this condition. Other possible causes include

  • Pressure sores
  • Skin irritation
  • Ingrown toenails
  • Broken bones
  • Pregnancy
  • Appendicitis

Autonomic Dysreflexia Risk Factors

The most common risk factors for AD are listed below:

Bladder problems

These involve:

  • Urinary retention
  • Urinary tract infection
  • Blocked catheter
  • Irritation of the bladder wall
  • Bladder stones
  • Overfilled collection bag
  • Non-compliance with an intermittent catheterization program

Bowel problems

These include:

  • Constipation or impaction
  • Digital stimulation or distention during bowel movement
  • Anal fissures or Hemorrhoids
  • Irritation or infection resulting from conditions like appendicitis

Bone ailments

These include:

  • Fractured or broken bone
  • Bone spurs
  • Other severe bone injuries

Skin Disorders

These involve:

  • An irritation directly below the level of the spinal injury
  • Ingrown toenails
  • Pressure sores
  • Burns
  • Tight clothing that can put pressure on the skin

Other Factors

Some of the other causative factors:

  • Labor and delivery
  • Pregnancy
  • Menstrual cramps
  • Skeletal fractures
  • Acute abdominal disorders including colitis, gastric ulcer and peritonitis
  • Surgical and diagnostic procedures that can irritate the area beneath the level of injury
  • Drug reactions (including Sympathomimetics, Decongestants, narcotic withdrawal and Vasoconstrictors)

The demyelinating disease named Guillain-Barre syndrome can disturb the normal bladder, bowel and respiratory functions, leading to AD. Severe brain injury and head trauma can sometimes interfere with the reception of normal signals regarding the functioning of the bladder and the bowels which may finally cause Autonomic Hyperreflexia.

Autonomic Dysreflexia Signs and Symptoms

A patient may experience one or more of the following symptoms during an episode of AD:

  • The blood pressure may increase suddenly. This significant increase in the systolic and diastolic pressure is associated to the level of individual injury. The sympathetic system has more unregulated control in case of higher level of injury which leads to more significant increase in the blood pressure.
  • Bradycardia, occurring due to the stimulation of parasympathetic system for controlling the abnormal blood pressure level
  • Pounding headache due to increased blood pressure
  • Sweating in areas above the level of spinal cord injury, such as the shoulders, neck and face, because of the parasympathetic stimulation
  • Flushing (redness) of the face and neck
  • Cold and clammy skin, especially below the level of injury
  • Nausea
  • Anxiety
  • Blurred vision resulting from elevation in blood pressure level and parasympathetic stimulation of Oculomotor nerve
  • Decreased heart rate due to high blood pressure
  • Nasal congestion
  • Tightness in chest
  • Appearance of goosebumps

Autonomic Dysreflexia Prevention

It is a completely preventable disorder. Prevention is also very important as it is much more complex to treat an episode of this disabling and life threatening condition than preventing its occurrence. Taking proper care of the bowel, bladder and skin generally helps to avoid AD.

Bladder Care

The measures for taking care of the bladders include:

  • Regular catheter changes
  • Checking for any sign of UTIs or urinary tract infections
  • Regular examination, for any sign of kink in the tubing which leads to the urinary collection bag
  • Drinking plenty of fluids

In case of self- catheters, one should take care to do them frequently and keep it consistent with the fluid intake amount

Bowel Care

Taking care of the bowel involves:

  • Following a proper bowel emptying routine for avoiding complications like constipation
  • Maintaining a diet containing plenty of high fiber food
  • Drinking lots of fluids

Skin Care

This includes:

  • Checking the skin regularly for pressure injuries
  • Performing pressure relieving activities for relaxing the skin
  • Maintaining a proper position and posture in wheelchair
  • Avoiding skin injury by wearing protective clothes and shoes

Rehabilitation Program

Individuals with a spinal cord injury (SCI) should participate in some rehabilitation program to reduce the risks of developing Autonomic Hyperreflexia. The rehabilitation may include the following:

Physical Therapy

It can be highly beneficial for SCI patients; however it is very important for a physical therapist to have proper education regarding AD and its initial symptoms. The therapist should check the urinary catheter to look for any twisting or blockage after every session as abnormal positioning during some exercise may trigger the AD symptoms. Various muscle stretching and range of motion exercises are prescribed for individuals with a spinal injury. However, therapists should always take care that patients are not developing any signs of AD.

Occupational Therapy

An occupational therapist trains patients in various daily activities including proper bladder and bowel management. He also educates patients and their family members about the prevention strategies, symptoms and management of AD.

Autonomic Dysreflexia Diagnosis

It is not possible to diagnose AD with a single diagnostic test. A doctor studies the symptoms exhibited by the patient very carefully for making the diagnosis. A thorough medical exam and a complete nervous system test are usually performed by the physician. The patient should also inform the doctor about all the medications he or she is using or has used in the past as it helps the latter to determine the diagnostic tests to be used. The following exams and tests can be useful for diagnosing AD:

  • Blood tests and urine tests
  • CT scan (Computed Tomography Scan)
  • MRI (Magnetic Resonance Imaging)
  • Lumbar puncture
  • EKG (Electrocardiogram)
  • Tilt-table testing (for examining the blood pressure changes along with any change in body position)
  • Toxicology screening tests (performed to look for any drugs and medications in the blood stream of patients)
  • X-rays

Autonomic Dysreflexia Differential Diagnosis

The differential diagnoses for this disorder includes isolating its symptoms from conditions like Pheochromocytoma and Essential hypertension.

Autonomic Dysreflexia Treatment and Management

It is very important to start the treatment for AD at the moment the onset of the symptoms occurs. This is because a delay in treatment can be incapacitating or fatal for the patient. The treatment generally comprises of the following:

Picture 2 – Autonomic Dysreflexia Image

First Aid

The patient should remain in a sitting position or lie with the head raised for lowering the blood pressure. It is advisable to loosen any tight clothing and remove tight wrappings like straps and belts. The physician checks the blood pressure of the patient every 2-5 minutes to see whether the condition is getting better.

Treating the Principle Causes of Attack

Identifying and removing the main stimulus responsible for the AD episode is the main aspect of this treatment. The condition usually requires the following nursing interventions:

Bladder cure

It is important to check the catheter for kinks and removing any kinks present. Emptying the urinary collection bag and irrigating the catheter can also help to relieve the symptoms. One should remove and replace the catheter if it is not draining properly. Performing a straight catheterization with slow drainage for preventing the bladder spasms is advisable if the patient is using intermittent catheterization program.

Bowel cure

If the patient starts experiencing signs of AD during a digital stimulation, the care giver should stop the process of stimulation until the symptoms subside. A prescription anesthetic ointment can be used for suppressing the noxious stimulus. The care giver should also check the rectum of the patient to look for any stool obstruction. Applying the commode-based bowel evacuation can help to fight the symptoms if the episode occurs while performing bowel program in the bed. Using abdominal massage instead of a digital stimulation may also be helpful.

Skin cure

It is important to check for any tight clothing and remove or loosen them immediately. The care giver should also check for any toenail problems and pressure sores on the patient’s skin including the heels and soles of the feet.

Emergency Treatment

Obtaining emergency medical treatment is very important if the care giver or nurse fails to find the factor responsible for the episode of Autonomic Hyperreflexia. The patient should be taken to an emergency clinic where further instigation for the stimulus can be performed. The doctor may recommend admitting the patient in ICU for treating hypertension.


Medications are used if the doctor fails to detect the responsible stimulus or if the symptoms persist even after the suspected cause has been removed. Potentially useful medications include:

For immediate relief –
  • Procardia – 10 mg p.o. or sublingual
  • Nitroglycerine – 1/150 sublingual or
  • Nitropaste – 1/2 inch topically
  • Clonidine – 0.1-0.2 mg. p.o.
  • Hydralazine – 10-20 mg. IM/IV
  • Prazosin (Minipress) – 0.5-1.0 mg. daily
  • Clonidine (Catapres) – 0.2mg. p.o. b.i.d
For chronic or recurrent episodes of AD –

Autonomic Dysreflexia Prognosis

The prognosis of the treatment depends on the cause of the episode and varies from one patient to another. In cases where AD is triggered by some medication, the symptoms get better with the discontinuation of the medications responsible for them. However, the recovery depends on the efficiency of the treatment when the symptoms occur due to some other causes.

Autonomic Dysreflexia Complications

Various complications may result from side effects of medications used to cure AD. The medicines used for lowering blood pressure may make the BP decrease so rapidly that the patient may have nausea, dizziness and vomiting. Sometimes, the pulse rate of a patient drops significantly and can lead to cardiac arrest. Possible complications of severe long-term high blood pressure include:

  • Seizures
  • Stroke
  • Myocardial infarction
  • Pulmonary edema
  • Cerebral hemorrhage
  • Bleeding in eyes

High level of blood pressure can also be harmful for the kidneys. It can even cause death of a patient.   Autonomic Dysreflexia is a serious life endangering condition which requires immediate medical attention. It is important for SCI patients and their families to take all necessary measures for preventing the occurrence of the episodes. Various forums and support groups provide proper preventive measures and treatment guidelines for AD. However, there are various treatment options that help to relieve its symptoms and allow a patient to survive for a long time.

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