The physiology of autonomic dysreflexia

The physiology of autonomic dysreflexia

Posted by AskNurseLinda on Jan 2, 2017 10:00 am

b1f950bc52d1abf2cc541a9008aa0a05-huge-blMany people with spinal cord injury or disease talk about AD but what does it really mean, who gets it and why? All of these are very good questions. The answers are simple and yet not completely clear. Autonomic Dysreflexia is a confusing and an often conflicting concern of spinal cord function.

Autonomic Dysreflexia is a complication of spinal cord injury, particularly of the autonomic nervous system. The nervous system is a series of checks and balances as is the rest of the body. The autonomic nervous system controls the body’s automatic functions such as your heart beating and breathing. It controls activities that you do without thinking about doing it. These are things that happen automatically such as the rate of your heart beating, breathing, blood pressure control, digestion, all of the things that happen without your mind saying, ‘beat heart, breath lungs, ect.’ These things just happen. Your body adjusts these activities as needed.

Within the autonomic nervous system, there are two systems. The sympathetic nervous system speeds up your body such as raising your heart rate, raising your blood pressure and constricting blood vessels so blood circulates faster and harder. This part of the nervous system comes into action with physical exertion or when threatened. It is often thought of in the flight or fight syndrome when your body is getting ready for some sort of action. Most of the sympathetic spinal cord nerves exit at the thoracic level.

The opposite is controlled by the parasympathetic nervous system which calms the body’s actions. This system is often nicknamed the rest and digest system. Still, it is controlling automatic body activities but to reduce speeding up such as making digestion and defecation work, creating urine, and sexual arousal. Most of the parasympathetic nerves exit the spinal cord at the cervical and sacral spinal cord segments. There are several parasympathetic nerves but the important one for autonomic dysreflexia is the vagus nerve which have several exit points along the spinal cord.

Those that are most risk for autonomic dysreflexia are individuals with spinal cord injury or disease above the T6 level of injury. The vagus nerve starts all the way up in the brain but passes through the neck and thorax or chest to get to its destinations which are the heart, gut and other abdominal structures. As it moves along, it is mixed in a bundle of other nerves at T4. If messages are not transmitted from the brain correctly at this point in the spinal cord, the messages can get miscommunicated in this very important vagus nerve. These miscommunications can be jumbled in the ball of nerves making the vagus nerve react when it is not needed. Since no two injuries are the same, no two people have the exact same anatomy and the results of spinal cord injury can vary, there have been some individuals with SCI as low the T10 level of injuries with reports of having AD.

The symptoms of autonomic dysreflexia are a pounding headache, hypertension or high blood pressure, a very slow pulse or sometimes a very fast pulse, apprehension or anxiety (sometimes people say they ‘just don’t feel right’), changes in vision, nasal congestion, sweating, flushed skin, goose bumps, tingling and pupil dilatation. Below the level of injury, your body might be clammy or you might have chills. You can have one of these symptoms, a few or all of them. The most common is a pounding headache but not everyone has this symptom. Not all individuals with AD will have a dramatic symptom. Some people have just a slight headache or none at all but they will have other symptoms.

The diagnosis of autonomic dysreflexia is made when your blood pressure, which is controlled by the autonomic nervous system, becomes 20-30mmHg over your typical normal systolic blood pressure. This is the top number being 20-30 points higher than your normal. Since individuals with spinal cord injury typically run lower blood pressures, if you are 20-30mmHg higher, you might be in the adult normal blood pressure category. It is important to know what your personal blood pressure normally averages so you can inform health professionals if your blood pressure is now high due to AD. The elevated blood pressure is a result of the misinterpretation of nerve messages in the autonomic nervous system which is not being regulated by the sympathetic and parasympathetic nerves correctly.

Triggers for AD vary by individual. The most common cause is usually bladder or bowel distension. If the bladder is over filled or an indwelling catheter is kinked or the bowel is impacted, an episode of AD can be set off. Treatment is effective by removing the trigger such as unkinking the catheter, performing intermittent catheterization, manually removing impacted stool. Some individuals are very sensitive to any form of constriction such as a leg bag that is too tight around the calf. It may be lose when put on but might get tight during the day due to the bag filling with urine. Wrinkles in sheets has been known to set off an AD episode. Some individuals are so sensitive that even a light air current can trigger it. As technology develops, there are new stimulations of AD episodes. Computer monitors and TV glare have been more recent causes for AD episodes.

Autonomic Dysreflexia is a medical emergency. Your blood pressure can get so elevated that you can possibly have a stroke or it can even be fatal. Other complications of AD can be bleeding in the brain, stroke, retinal detachment, seizures and coma. Since there is known treatment for AD, these results are rare.

When an episode of AD occurs, be sure to elevate the head as a first treatment. The sudden elevation might trigger orthostatic hypotension and drop your blood pressure back down. Look for the source or trigger of the episode and eliminate it. The first check is for any distention in the bladder or bowel. If there is any constriction or pressure anywhere on the body, remove it. Turn off the computer or TV to see if that will relieve the blood pressure spike.

If you have just faint symptoms of AD, you will still need to remove the noxious stimuli. Wearing sunglasses or a hat to reduce glare can help. Some of the triggers can be reduced with minimal upset to your routine.

If you are so sensitive to AD that even an air current triggers an episode, but sure to sit out of range of the ventilation duct of the furnace or air conditioner. Cover with a light sheet if outside in the summer and bundle up in layers in the winter when going outside. Have your vehicle warmed before getting into it. Do whatever is necessary to avoid episodes. If AD becomes too prevalent in your life, there are medications that can help control it. You will have to be vigilant and exploratory in discovering what triggers an episode and thoughtful about simple techniques you can incorporate into your life to control it.

If you find you have continued episodes of AD due to certain circumstances such as continual bladder issues, look for treatments for the source. Changing your bladder routine or seeking treatments to avoid distention such as sphincterotomy for males to allow urine to freely flow out of the bladder, bladder augmentation or mitrofanoff procedure for easier catheterization will help. Eating or taking fiber, drinking water and use of stool softeners will help the bowel become soft and moveable. Check your skin to make sure there are no pressure areas or wrinkles where you are sitting or lying. Use pressure dispersion surfaces in bed and when seated as well as on your back rest and head rest, if used. Monitor your environment for temperature, glare, air flow currents and dress accordingly. Taking control of your environment and health will be productive.

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Re: The physiology of autonomic dysreflexia

Posted by chefkaren on Dec 4, 2017 6:10 pm

Can AD occur with lumbar level damage? I have a failed pelvic floor surgery with lots of discomfort. I was seen in ER over the weekend, and thought to have GI issues and elevated blood pressure. I have no history of it. I'm experiencing lots of numbness and tingling on the right side of my head and face-it comes and goes. It has me worried and anxious. My care team has repeatedly missedand/or ignored the fact that I am partially paralyzed after a misdiagnosed event of TM. Over and over, I am chastised, accused, humiliated for things I have no control over. It has been a nightmare and has cost thousands only to receive the incorrect treatment. I'm 61-female-have neurogenic bowel and bladder and my left leg is damaged up to the thigh. I can still walk with a cane, but the damage seems to have gotten worse over the past few years. This is the first time I have experienced this particular thing. It seemed to have begun after I tapered off of pain medicine--3 years in pain management. I just need some advice. I feel those entrusted to my care are missing the facts!

Re: The physiology of autonomic dysreflexia

Posted by AskNurseLinda on Dec 4, 2017 7:49 pm

Hi, Karen, AD can happen to anyone. Some people have autonomic injury without even having a spinal cord injury. So, you could easily have it based on you diagnosis or another issue altogether. Please let me know how you are doing after your neurology appointment. The neurologist is the perfect person to fugue it out as they will be able to examine you and perform a physical assessment. Nurse Linda

Re: The physiology of autonomic dysreflexia

Posted by chefkaren on Dec 6, 2017 6:48 am

Thanks, nurse Linda. After a visit to my Neurologist, I'm left with dibilitating symptoms and only a glimmer of hope that things will get better. She did, however, tell me that she did not feel that I was in any significant danger. The subject of AD was not discussed per se--but the possiblitity of an Auto-response to the discontinuation of the pain medicine--which was initially prescribed for nerve pain-seems more likely. She prescribed Clonidine and Baclofen to address the discomfort. It is so severe, that it has caused the nerves on the right side of my abdomen, face, and head, to be numb and tingling. I feel as if I were in a constant state of adrenaline rush. She also suggested that I talk to my psychiatric NP to see if she would prescribe some Klonapin-assuring me that this was the normal protocol in managing withdrawl symptoms. For whatever reasons, my NP would not prescribe the Klonapin--even at the request of my neurologist. The numbness and tingling extends to the right side of my head--the ear and jaw-and encases the entire right side of my abdomen. Ever since the misdiagnosed TM event in 2012--I admit I am always aprehensive and suspicious-fearing that my team is missing the point. I believe, that my individual symptoms, are secondary to my SCI. This only leaves me seriously uncomfortable and anxious. When coupled with the dibilitating numbness and tingling, sleeplessness, intermittant high blood pressure, and compromised female anatomy-my quality of life has all but disappeared. I can't seem to achieve any level of comfort-despite my own efforts. So--where does one go from here?

Re: The physiology of autonomic dysreflexia

Posted by AskNurseLinda on Dec 6, 2017 9:32 am

Karen, thank you for the follow up. After your neurologist's assessment, you know you do no have AD. That is the great news.

The issue is the continuous pain with sporadic elevated B/P. Your neurologist's assessment of sudden withdrawal from the medication is consistent with what happens when these drugs are stopped. Without tapering of these medications, the pain that they are treating intensifies. You seem to have quite a severe case of withdrawal. Your neurologist has offered some great advice to try to help your discomfort. There might be a medical reason for not prescribing additional medication.

It seems that you might be dissatisfied with your care. The course from here is to ask for a second opinion. A healthcare provider is usually not opposed to a 'second set of eyes' reviewing your case. That would be an option. The pain you are having from the withdrawal of medication will subside over time. The amount of time is different for everyone and is affected by amount and sensitivity. This will resolve but it will take some time. Nurse Linda

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