What is Autonomic Dysreflexia?
Autonomic dysreflexia is a condition that often develops soon after injury to the spinal cord, specifically when the damage is at or higher than the T6 level. This condition triggers a sudden, heightened reaction in blood pressure when stimulated, usually by bladder or bowel expansion. These stimulations tend to begin below the level of the neurological damage. Alongside a severe headache, slower heart rate, and a flushed face, symptoms often include pale, cool, and sweaty skin on the lower body. This condition can be life-threatening and affects about half or more of the potentially at-risk individuals. Thankfully, prompt identification and simple correctional steps by caregivers can relieve it. The condition has various names, such as autonomic hyperreflexia, hypertensive autonomic crisis, sympathetic hyperreflexia, autonomic spasticity, paroxysmal hypertension, mass reflex, and viscero-autonomic stress syndrome. These terms should not be confused with autonomic dysfunction, autonomic neuropathy, and dysautonomia, which refer to a wider malfunction of the autonomic nervous system, a separate issue.
The risk of developing autonomic dysreflexia increases with the level and completeness of the spinal cord injury. Approximately 90% of patients with cervical spinal or high-thoracic spinal cord injuries are susceptible to this disorder. A disorder of the automatic nervous system can result in an uncoordinated response, which can present a life-threatening situation with high blood pressure when there is a harmful stimulus below the area of the spinal cord injury. In around 85% of cases, the stimulus comes from a urological source – such as urinary tract infection (UTI), a full bladder, or a blocked catheter. There is an increased risk of stroke, three to four times higher than normal. Autonomic dysreflexia can occur up to 40 times a day in at-risk individuals. People with traumatic spinal injuries who also have autonomic dysreflexia have a noticeably higher death rate than those with similar injuries who do not have the disorder.
The first noticeable sign is often an intense headache that feels like throbbing. People with spinal cord injuries at or above T6 who report a severe headache should immediately have their blood pressure checked. If it’s high, there’s a possibility they have autonomic dysreflexia. The condition can be managed quickly, sometimes just by cleaning or changing their urinary catheter, and this can be life-saving. Regrettably, many healthcare professionals such as nurses, emergency room staff, and physical therapists are not aware of autonomic dysreflexia and can’t identify or treat it quickly. This lack of knowledge is concerning as early recognition and fast appropriate treatment can be the difference between life and death.
Luckily, most of these instances are fairly mild and can be managed at home by the patient and their caregivers without the need for immediate medical intervention. Severe, life-threatening situations are typically only seen by healthcare professionals who work at specialized high-level care centers. So a lot of healthcare providers, including emergency personnel, may not often come across this condition in its severe form and so might not be knowledgeable about its early signs or swift treatment practices.
What Causes Autonomic Dysreflexia?
The cause of this condition is an injury to the spinal cord, typically at or above a certain point in the spine known as the T6 level. You can tell an episode is happening when the systolic blood pressure (the pressure in your arteries when your heart beats) raises at least 25 mm Hg above what’s normal for that person. A serious episode usually involves the systolic blood pressure going up to 150 mmHg or more than 40mmHg above the person’s usual level.
The more severe the injury, and the higher up it is on the spine, the worse the cardiovascular problems can be. The harshness and how often these episodes happen also depend on the level and completeness of the spinal cord injury. For instance, patients with a total spinal cord injury are over three times as likely to develop this condition than those with only a partial injury.
Interestingly, while this issue can occur in the first days or weeks following the initial trauma, it generally does not develop until after the period when reflexes have recovered from the spinal shock caused by the initial injury. The fastest one case was reported was four days after the injury. Most patients who end up developing this condition do so within the first year after their injury.
Risk Factors and Frequency for Autonomic Dysreflexia
Autonomic dysreflexia is a condition that occurs in a significant percentage of patients who have a spinal cord injury above a certain point, specifically the T6 level. Roughly 48% to 70% of these patients can develop this problem. Conversely, if the spinal cord injury is below the T10 level, the chance of developing autonomic dysreflexia is quite low. It’s worth noting that this condition has also been reported, albeit infrequently, in patients with non-traumatic spinal cord injuries caused by things like radiation treatments or certain drugs.
Individuals susceptible to this disorder might have had previous episodes, which can be found in their medical or personal history. However, healthcare professionals need to be aware that there could be a first-time occurrence of autonomic dysreflexia even without a prior history. This emphasizes the need for alertness in spotting the symptoms of this condition.
Signs and Symptoms of Autonomic Dysreflexia
Autonomic dysreflexia is a health condition that can result in various symptoms, such as:
- Severe headache
- High blood pressure
- Excessive sweating and flushing above the area of injury
- Cold and pale skin below the area of injury due to intense narrowing of blood vessels
- Problems with vision
- Constricted pupils
- Stuffy nose
- Feelings of extreme anxiety or dread
- Nausea and vomiting
- Dizziness
The first sign folks usually notice is a severe headache that comes on suddenly. This is caused by the blood vessels widening above the level of injury and combined with extremely high blood pressure, there’s a risk of suffering a stroke.
High blood pressure in this case can also not show any symptoms, or it can be so severe that it causes a hypertension crisis. This could lead to complications like fluid in the lungs, heart dysfunction, retinal detachment, brain hemorrhage, seizures, or even death. Patients with injuries at the T6 level usually have systolic blood pressures (the top number in a blood pressure reading) between 90 and 110 mmHg, but it’s essential to compare this to the patient’s normal levels. The heart rate can also decrease drastically, or it can speed up, causing heart rhythm problems.
The combination of the sudden increase in blood pressure and the widening of the blood vessels in the brain increases the risk of a hemorrhagic stroke, which can be fatal.
It’s crucial to monitor any patients who have paralysis in all four limbs or in the legs and complains of a severe headache or is discovered unconscious. A blood pressure check should be done immediately to screen for possible autonomic dysreflexia by comparing it to their normal levels. When the systolic blood pressure is more than 150 mmHg or more than 40 mmHg above their usual level, it’s likely they’re experiencing autonomic dysreflexia and appropriate steps should be taken.
Testing for Autonomic Dysreflexia
If you have had autonomic dysreflexia episodes before, your doctor will note down the events that triggered those episodes, if known. Since this condition is related to your autonomic nervous system – which controls body functions like blood pressure and heart rate – your doctor will closely monitor your vital signs and watch for symptoms. It’s important for your doctor to know your usual blood pressure for comparison in the future. Just so you know, many individuals with spinal cord injuries tend to have low blood pressure, and more than half of the patients with autonomic dysreflexia experience a sharp drop in blood pressure upon standing up.
The first thing your doctor will consider is whether you are at increased risk of having autonomic dysreflexia. This risk is significantly higher if you have a spinal cord injury at or above the T6 level, which is the sixth vertebra down in your thoracic spine. The key initial symptom of autonomic dysreflexia is often a severe headache caused by dilation (or expansion) of the blood vessels in the brain. If you experience this, the next step is to check your blood pressure. If it is higher than usual, you could be at high risk of an episode of autonomic dysreflexia. As a rule of thumb, a systolic blood pressure (the top number in a blood pressure reading) higher than 150 mmHg or more than 40 mmHg above your usual levels could indicate autonomic dysreflexia.
The likelihood of autonomic dysreflexia is predicted by the level of your spinal cord injury, whether it’s complete or partial, and whether you have a condition known as neurogenic detrusor overactivity, which affects the muscle in your bladder’s wall and may cause urinary problems.
Treatment Options for Autonomic Dysreflexia
If you have experienced prior episodes of a condition called autonomic dysreflexia, which is a sudden, dangerous spike in blood pressure, it’s best to keep note of what typically triggers this and how you usually manage it. Individuals who frequently experience this condition often know a lot about managing it and are equipped to implement a treatment plan. It’s also strongly suggested for patients likely to experience autonomic dysreflexia to carry around an emergency kit that includes necessary medications and an explanation card about the condition and urgent treatment.
So, what should you do when an episode occurs? Your initial reaction should be to sit upright with your legs down and remove any tight clothing or devices that might be restricting you. This helps in lowering your blood pressure by causing your blood to pool in the abdominal and lower extremity vessels. Besides this, it’s essential to constantly monitor your vital signs and identify the trigger as soon as possible. Blood pressure should be checked frequently, at least every 5 minutes.
Most frequently, triggers are bladder and/or bowel distension, with an overfull bladder being the top culprit. So, if you have a catheter or tube placed in your bladder to help it drain, it should be inspected for any issues such as blockages, malfunctions, or incorrect placement, and a urine test should be done to check for a urinary tract infection. The catheter should be flushed using normal saline to ascertain its working, although this flushing should be minimal. If there is any uncertainty about the catheter’s functionality, it should be replaced right away.
If managing your bladder doesn’t help control blood pressure, the cause could possibly be a bowel issue. Here, a rectal exam should be done carefully to evaluate for any obstructions keeping in mind that rectal stimulation can worsen autonomic dysreflexia. If bladder and bowel problems are ruled out, a comprehensive search for other causes should be undertaken. Common triggers could be skin lesions, infections, fractures, medication effects, gastric issues, or recent injuries.
If the cause of the autonomic dysreflexia episode can’t be identified and the usual measures do not help in controlling the blood pressure, emergency treatment needs to be initiated. Nitroglycerine 2% paste is the usually suggested initial treatment for high blood pressure in cases of autonomic dysreflexia. The paste should be placed on the skin above the level of the spinal cord injury, and can be easily removed when the blood pressure issue is resolved.
In severe cases, you may need to be hospitalized, especially if the underlying cause is unknown, the treatment is not effective, or if you are pregnant. Women with spinal cord injuries at or above the sixth thoracic vertebra (or T6 level) are at risk for experiencing autonomic dysreflexia during labour and delivery. Therefore, knowing how to manage such a condition during pregnancy is crucial for both the patient and the medical team.
Lastly, while it may seem quite specific, individuals with autonomic dysreflexia are discouraged from intentionally triggering an episode to enhance their athletic performance for sporting events. While it has been known to enhance performance, the risks and potential harm outweigh any perceived benefits.
What else can Autonomic Dysreflexia be?
There are several conditions and situations that could potentially cause similar symptoms. These include:
- Acute glomerulonephritis (a type of kidney inflammation)
- Anxiety
- Cushing’s syndrome (a hormonal disorder)
- Use or overdose of certain drugs, such as stimulants, alcohol, cocaine, or levothyroxine
- Hyperaldosteronism (overproduction of the hormone aldosterone)
- Hyperthyroidism (overactive thyroid gland)
- Intracranial hemorrhage (bleeding within the skull)
- Ischemic stroke (a blockage in an artery supplying blood to the brain)
- Nephritic and nephrotic syndrome (kidney disorders)
- Polycystic kidney disease (a condition causing numerous cysts in the kidneys)
What to expect with Autonomic Dysreflexia
The outlook for autonomic dysreflexia, a condition affecting the nervous system, is generally good so long as the condition is identified early. It’s crucial that both patients and their caregivers receive proper education about the condition and make the necessary precautionary measures. Quick and accurate treatment is also important.
However, if autonomic dysreflexia is not recognized or treated in a timely way, the consequences can be very serious. Thankfully, it’s not common for this condition to cause death.
Possible Complications When Diagnosed with Autonomic Dysreflexia
The most dangerous complication of autonomic dysreflexia is a bleeding stroke, which can be severe and even life-threatening. If not treated promptly, autonomic dysreflexia can cause persistent and extreme high blood pressure. This can lead to various problems like heart muscle damage or heart attack, kidney failure, fluid build-up in the lungs, bleeding in the retina or brain causing a stroke that could be disabling or deadly.
Research into patients with autonomic dysreflexia who had serious complications found 32 reported cases. Unfortunately, around 22% of these patients passed away due to problems directly related to an autonomic dysreflexia episode. Most of these severe complications (72%) affected the central nervous system, while 22% involved the heart and blood vessels, and 6% were lung-related.
Other complications could arise due to their existing spinal injury such as pressure sores, bedsores, constipation, and urinary tract infections. However, in patients who are likely to have severe episodes of autonomic dysreflexia, such health issues could trigger a dysreflexic event.
More Serious Complications:
- Bleeding stroke
- Heart muscle damage or heart attack
- Kidney failure
- Fluid build-up in the lungs
- Bleeding in the retina or brain (stroke)
- Death due to complications related to autonomic dysreflexia
Existing Issues That Can Lead to More Serious Complications:
- Pressure sores
- Bedsores
- Constipation
- Urinary tract infections
Preventing Autonomic Dysreflexia
Patients who are susceptible to a condition called autonomic dysreflexia and the people who take care of them, need to be well-informed and completely educated about this disorder. Autonomic dysreflexia is a condition where your body’s involuntary functions (like heart rate and blood pressure) become overactive and can cause dangerous symptoms. It’s important to understand how to recognize this condition, its seriousness and how to deal with it immediately if something happens.
It may also be wise for these patients to carry an emergency treatment bag when they travel. This bag should contain information about autonomic dysreflexia, instructions on what to do (treatment), and the basic supplies needed to handle a situation involving the disorder. This preparedness could help manage and correct the condition swiftly, reducing potential harm.
