Autonomic Dysreflexia – Hyperreflexia

When a strong sensory impulse is sent via the spinal cord to the brain it envokes a massive sympathetic reflex and hypertension. Blood pressure rises often resulting in chronic headaches, blurred vision, blotchy skin and sweating. Also known as hyperreflexia, autonomic dysreflexia is a potentially life threatening condition usually affecting individuals with spinal cord injury from a lesion at or above the T6 neurological level. Common amongst quadriplegics early recognition of symptoms and treament can avoid the associated dangers of elevated blood pressure, brain hemorrhage, burst blood vessels, stroke and fitting. If you suffer from autonomic dysreflexia it’s important to educate family, carers and medical professionals about the syndrome and its management.

Epidemiology Of Autonomic Dysreflexia

Dysreflexic Headache
Dysreflexia causes chronic headaches
Below the level of spinal cord injury intact peripheral sensory nerves transmit impulses that ascend in the spinothalamic and posterior columns to stimulate sympathetic neurons located in the intermediolateral gray matter of the spinal cord. A sympathetic production of various neurotransmitters (norepinephrine, dopamine-b-hydroxylase, dopamine) from cerebral vasomotor centres increases but typically are unable to pass below the level of spinal cord injury. Vasoconstriction (narrowing) in arterial vasculature below the SCI and vasodilation (widening) of pain sensitive intracranial vessels above the SCI occurs creating severe headaches.

Vasomotor brainstem reflexes attempt to lower blood pressure by increasing parasympathetic stimulation to the heart through the vagus nerve to cause compensatory bradycardia. This reflex action cannot compensate for severe vasoconstriction, explained by the Poiseuille formula where pressure in a tube is affected to the fourth power by change in radius (vasoconstriction) and only linearly by change in flow rate (bradycardia). Parasympathetic nerves may also prevail above the level of injury which may be characterized by profuse sweating. Vasodilation may also display as blotchy skin, blurred vision and so on. Once the inciting stimulus is removed, reflex hypertension (hyperreflexia) resolves.

Autonomic Dysreflexia In Plain English

When a person with a spinal cord injury (lesion) at or above T6 such as a quadriplegic or tetraplegic breaks their leg the pain messages sent to the brain which usually have you on the ground screaming get mixed up and lost. I often explain it as cutting through a telephone cable with 100,000 wires in it, twist one side 90 degrees and press them back together. Not much chance your call will get through and if it does it will probably be a wrong number.

Finding the source of dysreflexia
Finding the source of dysreflexia

Two years ago I broke my Tibia (shinbone) clean in half and fractured Fibula (thinner one behind it). Broken leg pain messages reached my damaged spinal cord area near C4 and couldn’t go any further. I only knew it was broken because it went off like a firecracker, snap! The message “this hurts” from my leg got transposed at the damaged section C4 of my spinal cord into let’s raise his blood pressure. I developed a mild headache and later a little sweating — autonomic dysreflexia.

An average blood pressure for people with a T6 spinal injury is commonly 90-100/60 when lying and lower when sitting. A BP of 130/90 is considered slightly high and if untreated it can rapidly rise to extreme dangerous levels like 220/140. I myself with C4 quadriplegia once hit 220/160 due to a blocked catheter. I displayed all the classic symptoms. Luckily once layed on a bed the blockage released filling a 2 litre drainage bag in a matter of minutes. I gained instant relief. You would think a badly broken leg would have been worse, but not in my case. Not everyone with a T6 or higher level of spinal cord injury experiences autonomic dysreflexia and the severity will vary per person but in all cases where it does occur it warrants immediate attention.

Common Autonomic Dysreflexia Symptoms

  • Blotchy red, rash like, flushing skin
  • Blurred vision
  • Headache
  • High blood pressure

Possible Autonomic Dysreflexia Symptoms

  • A sudden significant rise in systolic and diastolic blood pressures (usually associated with bradycardia). The normal systolic blood pressure for SCI above T6 is 90-100mm Hg
  • Difficulty breathing
  • Dizzyness
  • Goose bumps above or below the level of the spinal cord injury
  • Nasal congestion
  • Profuse sweating above the level of lesion especially in the face neck and shoulders may be noted but rarely occurs below the level of spinal cord injury because of sympathetic cholinergic activity
  • Spots may appear in the persons visual fields

Occassionaly no symptoms are observed besides elevated blood pressure. Dysreflexic episodes can be triggered by many things though painful, strong irritating stimulus below the level of the spinal cord injury are most frequently the cause of an autonomic dysreflexic reaction.

Causes Of Autonomic Dysreflexia

  • Appendicitis or other abdominal pathology trauma
  • Bladder distension
  • Blisters
  • Blocked catheter
  • Bowel distension
  • Bowel impaction
  • Broken bones fractures or other trauma
  • Burns or sunburn
  • Constrictive clothing shoes or appliances
  • Contact with hard or sharp objects
  • Cystoscopy
  • Deep vein thrombosis (blood clot in vien or artery)
  • Detrusor-sphincter dyssynergia
  • Ejaculation
  • Epididymitis or scrotal compression
  • Gall, bladder or kidney stones
  • Gastric ulcers or gastritis
  • Gastrocolic irritation
  • Hemorrhoids
  • Heterotopic bone
  • Ingrown toenail
  • Insect bites
  • Invasive testing
  • Menstruation
  • Pain
  • Pregnancy, especially labor and delivery
  • Pressure sores or ulcers
  • Pulmonary embolism (blood clot in lungs)
  • Sexual intercourse
  • Sudden temperature changes
  • Surgical or diagnostic procedures
  • Testicular compression
  • Urinary tract infection
  • Urodynamics
  • Vaginitis

It is easier to assist a dysreflexic person when two carers are present, one can monitor blood pressure while the other provides treatment, but this may not always be possible. The person with a spinal cord injury is usually aware of dysreflexia and will often be able to suggest possible causes. In any case it is important that the symptoms are relieved quickly and their BP lowered. Treat all episodes of autonomic dysreflexia as a medical emergency but stay calm and avoid leaving the person alone.

Initial Treatments For Autonomic Dysreflexia

  • Ask if they have just taken a drug to control autonomic dysreflexia
  • Ask the individual and carer if they suspect a cause
  • Elevate the head and lower legs if possible (this will help lower BP until a cause is identified)
  • Loosen any constrictive clothing
  • Check bladder drainage equipment for kinks or other causes of obstruction to flow such as catheter blockage, leg bag problems or an overfull leg bag
  • Monitor BP every 2-5 minutes
  • Avoid pressing?on the bladder

Further Treatments Of Autonomic Dysreflexia

If the person has an Indwelling Catheter or Supra Pubic Catheter:

  • Empty urinary drainage devivce and determine whether or not the bladder is empty, ask if volume is reasonable considering fluid intake and output earlier that day
  • If the catheter is blocked, irrigate GENTLY with no more than 30 mls of sterile water. Drain the bladder slowly, 500 ml initially and 250 ml each 15 minutes afterwards to avoid a sudden drop in blood pressure
  • If this is unsuccessful recatheterize using a generous amount of lubricant containing a local anaesthetic e.g. 2% lignocaine (Xylocaine) jelly
  • Where constipation is suspected check the rectum for faecal loading
  • If the rectum is full check the blood pressure before attempting manual evacuation
  • Gently insert a generous amount of lignocaine jelly into the rectum and gently remove the faecal mass – note: if symptoms are aggravated stop immediately and seek an alternate method of evacuation such as supositories or laxettes

If elevated blood pressure does not start to fall within one or two (1-2) minutes of the above proceedures and the cause cannot be determined treatment with a short-acting anti-hypertensive medication should be commenced concurrently with the search for and treatment of the cause. The blood pressure threshold at which medication should be given may vary a little depending on the individual and type of intervention being undertaken. In general if a systolic blood pressure greater than 170mm prevails consider use of a blood pressure lowering medication.

Glyceryl Trinitrate 

NB: DO NOT use glyceryl trinitrate if sildenafil (Viagra), or vardenafil (Levitra) has been taken in the previous 24 hours or tadalafil (Cialis) in the previous 4 days. Give one spray of glyceryl trinitrate (Nitrolingual Pumpspray) under the tongue. During administration the canister should be held upright and the spray should not be inhaled.

OR: Place a glyceryl trinitrate tablet (Anginine) under the tongue.

OR: Apply 5mg, transdermal patch to chest and upper arms according to manufacturer’s instructions. Remove patch once BP settles or if the BP drops too low.

A hypotensive response (lower blood pressure) should begin within 2 to 3 minutes and last up to 30 minutes. A second spray/tablet may be given in 5 -10 minutes if the reduction in the blood pressure is inadequate or if the blood pressure rises again. If glyceryl trinitrate is not available or unsuitable (e.g. within 24 hours of sildenafil use) give one 10 mg nifedipine tablet (not a slow-release tablet) crushed, mixed with water and swallowed. Avoid sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) for at least 48 hours after a severe episode of autonomic dysreflexia.

Botox Trials On Autonomic Dysreflexia

A Taiwanese study recently indicated that for patients with Spinal Cord Injury who have detrusor sphincter dyssynergia, using a combination of fluoroscopy and electromyography to localize the external urethral sphincter with a Foley catheter employed to visualize vesicourethral anatomy, makes transperineal injection of botulinum toxin (botox) type A into the external urethral sphincter safe accurate and easy to perform. Such injections have been shown to reduce the occurrence and severity of autonomic dysreflexia as well as vesicoureteral reflux, hydronephrosis, and urinary tract infection.

Kind Regards
Graham Streets
MSC Founder


  • Autonomic Dysreflexia in Spinal Cord Injury : Treatment & Medication by Denise I Campagnolo. Barrow Neurology Clinics. St Joseph’s Hospital and Medical Center. Investigator for Barrow Neurology Clinics.
  • Director NARCOMS Project for Consortium of MS Centers.

31 thoughts on “Autonomic Dysreflexia – Hyperreflexia

  1. Graham..Thx muchly for the article. I’m a partial Tetraplegic (I’m glad to see the term tetra finally coming in) C3-7. In rehab I ended up on a plymph too many times and would get wheeled back to my room. I used to pass out with mine. The neat thing is that I get 15 – 30 seconds notice before passing out… enough time to warn my attendant. Once I woke up with 2 Physitrists, 4 Nurses and a couple Physio’s peering down at me. How’s that for getting attention! It was the only time I could sweat.

    Your elevated BP figure is bang on. As time has worn on the frequency and severity have decreased, but I still get a milder form often with UTI and exercise. Enough of my ramblings. Your article was greatly needed and fills a knowledge gap for many of us. In your funny Aussi terms “Good on Ya, Mate” Cheers, BobS

  2. Thanks BobS, people often ask me what tetraplegia is. I answer quadriplegia. They say no, I know what quadriplegia means but what is tetraplegia? They are the same thing. Tetra is greek while quadra latin, both mean four (4). Plegia is also greek meaning paralysis. The term tetraplegia is most common in Europe.

    I can see why quadra might be seen as the odd one out and in 1991 a review of the American Spinal Cord Injury Classification system suggested tetra be used for global uniformity but it’s been slow to be adopted. In America, Asia, Australia and so on quadriplegia is most common.

    Penta is also greek meaning five, a pentaplegic is a person who has paralysis in all four limbs and the neck or head. If I state I have plegia in my legs people step back, “You got what?!” like I’m some infectious hazchem spill on wheels. I’m a tetraplegic usually brings a blank deer in the headlights stare, like they have an idea but feel bad not knowing exactly what it means. I’m a quadriplegic and they all say ohhhhh right. I wonder if the reverse happens in Europe.

  3. I have a chronic AD problem which has become life threatening; my blood pressure is spending too much time extremely elevated. 185/115 Is not uncommon. Unfortunately the folks at the Tampa VAMC have done little to track down the cause. I think it may bowel related and am considering a colostomy, I also experience extremely high BP during bowel care. I?ve been forced to sleep on my sides at night because my pressure is slightly better although it still gets elevated seemingly without cause. What complicates matters is I don?t sweat when AD, I can tell when it?s my bladder by a slight flashing in my head, but unless my pressure reaches 220/125 and I get a headache I?m clueless when it?s elevated. As a result I spend hours with my diastolic over 100. I have a broken hip, which they will not replace, but I can honestly say that it results in only 25-35% of my AD problems. I need to find a doctor and/or that specializes in finding the cause of my AD, any suggestions?

  4. Hi daniel, what is your level of injury? A broken hip unmended over time could increasingly cause autonomic dysreflexia. Any broken bones, deep cuts, etc should be treated like they would in any person. I’d be pushing to have that hip fixed, if for nothing more than a %25 improvement it would be worth it. Just because you can’t “feel it” is not reason enough for them to ignore.

    A colonoscopy sounds like a good idea. Our body often finds a way to tell us what’s wrong. Rule things out one by one, ingrown toenails, ultrasound kidneys/bladder, abdominal xrays and so on, explore all the causes we listed here. I just noticed, one not on the list, if you use a wheelchair make sure you are not sitting on your testicles all day, it can cause AD. I’ll add it to our list.

  5. HI daniel, read your comment and I agree with Graham, having an inability to completely feel is a very poor excuse for not treating your hip. Finding the reason for your raised BP is important to your well being. Good luck with all your investigations

  6. over active bladder turned out to be my problem for years. oxy butinal toltally fixed it. what a relief

  7. Need advice-my cousin is a quadriplegic and recently fell out of his w/c and fractured his femur. The ortho doc didn’t want to do surgery due to possible infection with such loss of circulation to the area. I feel he needs more tx. It isn’t even aligned or air-casted.

  8. Hi vicki I am a ortho nurse and specialise in wounds. We fix factored femurs all the time and yes circulation is an issue in anyone with limited movement. However it is not unreasonable to expect this type of fracture to be at least stablised. We use alot of plates and screws and intermedulary nails which minimise the size of entry wounds lessening the chance of infection. Leaving a femur fracture unstable puts the person at risk of major bleeding. Deep vein thrombosis and embolisms in the heart and lungs I think I would be seeking further opinion from a different specialist. Sometimes the doctors dont look at the patient just the injury

  9. I ended up getting a colostomy that solved my blood pressure problems. Unfortunately I still have a broken hip. Every doctor I met said because of osteoporosis I am not a candidate for a hip replacement.

    Vicky, I would advise your cousin to raise whatever fuss required to get more treatment.

  10. Thanks SUE and DANIEL for your input. He is at Ortho today to get some answers and discuss the surgery. I also want him to hook up with this web site. Thanks-Vicky

  11. FYI- my cousin is having surgery Thursday for his fx femur. Thanks for the concern. I gave him this website and hopefully he can communicate with with others who have issues like his. Vicky

  12. Great news hope it all gos well this is a great web site for friends and family as el as people who ate affected by disability I will be recommending it to everyone I no even a few surgeons lol

  13. Even though I am a c5/c6 quad, I did not realize the severity of autonomic signals. To bad more hospitals, including acute care, don’t knownabout this. The last hospital I was in had no idea why I was sweating all the time and why my spasticity was so bad. NOW MY MOM, AND CAREGIVER, has more to look for and can tell what to try and fix because of your article.

  14. I am a c4 quadraplegia, 78 years old, I’ve been a quad since an accident @ 21years old.
    I have AD, the sweating has been getting worse in my old age. Your article was helpful!!!

  15. i’m c4-c5 quad, whenever i lay down or remove/put on clothes i get a throbbing headache any slight AD givesme it. it happened out of no where. anyone have an answer? i’m clear of UTI.

  16. Tammy, it could be anything from constipation to kidney stones. If it persists more than a week you might want to see your doctor.

  17. Hi , That was a great article .
    My boyfriend who is C3/4 had cellulitis which may have got into the body through his suprapupic catheter.It started on his side and by the time they diagnosed it it was across his butt ,down his thighs and up his back.
    After a week of strong IV antibiotic and 10 days of oral antibiotic that is gone but now he cannot sit on his chair without sweating . His BP is normal for him but this has been going on for two weeks without letting up. Very frustrating .Any ideas?

  18. Hi Brenda, is he showing any signs of autonomic dysreflexia besides sweating? As sympathetic responses can vary greatly between spinal cord injuries of same levels it’s really hard to say. It could be a reaction to the antibiotics, pain from the old wound sites being under pressure, infection still existent, or the body adjusting to being infection free. We really cannot say. I am not a doctor, I suggest a re-test for infection by a doctor and avoid, or at least limit, any activity that causes the sweating. After a pressure area heals over it’s important to slowly and gradually increase sitting up time (or wherever the cause of pressure is) or it will simply break down again. It’s the last thing you want to hear after months in bed I know, but it proves a faster permanent recovery. Starting 1hr/wk, 2hr/wk, 3hr/wk etc.

  19. Hello:) I have been having AD-like symptoms after a severe whiplash injury after a motor vehicle accident 5 yrs ago. I injured c5/c6 (where the pain is) and lower back. I had never had severe elevated blood pressure or weird sweating beforehand. it seems to happen when I bend my lower back or turn my head to the right or look down. This reaction is scarey and annoying. When I was undergoing physiotherapy this happened a lot and nobody seemed to know what was going on and I almost passed out at times which of course freaked them out. The only person that knew a bit about it was the chiro on staff and he was concerned and sent me for MRI. It revealed nothing broken so my MD just put me on Norvasc and laughs it off. Is it possible to have AD without being paralyzed?? My lower back injury has made me have some issues with bladder control and I find that when my bladder is full I can’t stop sweating and I need to get to a bathroom quickly. When I sit in my recliner with legs elevated and slightly reclined my pressure goes to normal and sweating goes away in about 10 mins. Any hints on whether this is all in my head or not is greatly appreciated:) Ty!

  20. Of all the frustrating things which go along with my SCI AD is one of the most frustrating. Everytime I ejaculate my blood pressure rises and I get a huge heache. This has lead me to stop any sort of activity which leads to it. Though the joy is only 5% of what it use to be this at least helped feeling more like a man. I wish there was some drug which could reduce this.

  21. Hi, my husband has c5\c6 injury. Can you let us know if dysraflexia can also present as low blood pressure? Trevor, my husband has had severe episodes of bp being as low as 58\50 the last time was a week ago when he was unconscious and briefly stopped breathing. He wonders if trapped wind is causing the low bp as he suffers terribly from not being able to free gas that builds up during the day and night. Bp still low when going from lying to sitting. Any advice/information would be gratefully received because doctors don’t seem to have a clue. Thanks

  22. Hi Angela, you were on the right track but it’s not called autonomic dysreflexia or hypertension, rather orthostatic hypotension (hyper-increase hypo-decrease).

    In able-bodied individuals, both heart rate and blood pressure are controlled by coordinated inputs from two components of the autonomic nervous system: the sympathetic and parasympathetic. These two systems generally have opposing roles and are activated according to the needs of the individual. The parasympathetic nervous system is dominant during rest. When stimulated, this system acts to decrease heart rate. The sympathetic nervous system, on the other hand, is largely excitatory, and can be simplistically considered as that which prepares the body for an emergency, forming part of the well-known ‘fight and flight reaction’, and typically counteracts the parasympathetic nervous system.

    SCI patients are frequently troubled with sudden falls in blood pressure upon postural change, or following prolonged periods of sitting (orthostatic hypotension) characterised by dizziness, lightheadedness or even syncopal events. Conversely, SCI individuals can also be affected by sudden bouts of hypertension triggered by afferent stimuli below the level of the spinal cord lesion (autonomic dysreflexia) presenting symptomatically with pounding headache and upper body flushing. Previously, it was felt that the hypotensive episodes were confined to the acute period following SCI, and autonomic dysreflexia to the chronic phase of SCI. However, it has also been shown that autonomic dysreflexia can present in the early phases of SCI, and that orthostatic hypotension can persist for years, and often becomes worse with time.

    Possible causes of orthostatic hypotension:

    1. Sympathetic nervous system dysfunction
    2. Altered baroreceptor sensitivity
    3. Lack of skeletal muscle pumps
    4. Cardiovascular deconditioning
    5. Altered salt and water balance

    There is a fantastic article well worth a read here.

  23. My dad is an incomplete C4 quadriplegic, his accident happened in July 2013 so we’re still pretty new at this and trying to figure everything out. The biggest issue for him has been the blood pressure!! He sufferes from both OH and AD; he can go from one extreme to the other in a matter of minutes. He had been doing well until last week, the AD has been out of control. A few days ago, he passed a kidney stone and that is what lead me to this forum; we believe he may still have some stones present and are literally awaiting a call from his Urologist now about what to do next.
    Thank you Graham, for the article about OH!! My dad has been to a number of doctors and none of them have any idea what the problem is. I printed the article and Dad will be giving it to his Physiatrist at his next appointment!! Hopefully it will give the doctor some insight and perhaps lead to some type of management for my dad!

  24. Hi Jackie, glad to hear your Dad is on the mend and collectively we are educating some of the educated. One kidney stone is often followed by more, if not sooner later, so ultrasound and abdominal x-rays should be conducted yearly. As a C4 quadriplegic in Australia I receive a letter yearly reminding me to come in for free ultrasound and abdominal x-rays. Sometimes I skip a year. In your fathers case yearly checks are advisable. Breaking up stones with a laser makes them much less painful to pass. I’ve often found people prone to kidney stones have a tendency to also develop gall stones, which can be even more painful, so keep that in mind. Diet can play a big part in avoiding any stones. Thank-you for posting me a note.

  25. Hi all, I have a c5/c6 incomplete injury of 19 years. I have been having consistent AD with every bowel movement over the years but it goes away immediately after. I have a small fishes, a little prolapse and a few hemorrhoids that have gotten worse this past year. The last few weeks my AD has not gone away at all until I recline in my chair every hour. Spasms, sweating, headache, feels like razor blades are cutting my chest skin. I must get surgery to alleviate this because I live an active life and can’t keep reclining every hour. Can anyone share their hemorrhoid/anal problem surgery experiences with me? Im so nervous to cut because every time I get a wound and it heals, it seems that the area has super hyper sensitivit nerve pain forever.

  26. I have a friend who suffers from autonomic dysreflexia and the doctors in our area don’t know much about this. Does anyone know of a good doctor in central Illinois that specializes in this???

  27. Great to read everyone’s comments. I am an incomplete C6-7 quad… 35 years since my injury. I walk and have had the great fortune of a pretty good recovery. As I age I have to attend to fairly regular problems with bladder & it’s not emptying properly which causes infection. I use as much as I can to keep this in check including ensuring I drink sufficient water especially in hot weather, air conditioning, central heating, and if eating salty foods. I try to ensure that I empty fully even if it means tapping to void twice or three times before leaving the house.

    I have had some issues with AD in recent years and as some of you have experienced I have found the emergency wards of hospitals a place where everyone seems to be flummoxed and go around in circles with staff always routinely undertaking the normal tests over and over to prove that I am a quad but not being able to ascertain further any problems which reflect similar symptoms to those of any neurological disorders. I noticed myself over time that I was having mild to serious AD symptoms, ending up with ectopic heart beats, fainting, headaches & balance problems, sweating and generally feeling like I was dying. I was tested for so many things, medical staff scratching their heads, because, as a person who just doesn’t look like I have a spinal injury they weren’t even considering AD. I began to realise that some of the weird feelings I experienced over the years were at least a mild AD or at the very least a warning sign of something being amiss, like a bladder infection. But the real problems have occurred when I was huge amounts of stress and often as a result of a lack of fluids, but also since I had a serious leg break and now have a titanium rod & screws in my tibia. I wonder from time to time if this is causative of some of the reactions I have. It is now 2 years since the more serious AD and I believe that the increased fatigue and stress played a part in my reactions, and now I try to drink more water!

    Presently I am wanting to chat about anyone like me who has increased tightness in the psois, the adductors, and external rotators. Mine a tightening and causing my limp to be worse & tightening the lower back with greater stiffness all around, in spite of my working hard to stretch these areas. Any ideas??

  28. Has anyone done an MRI on your original injury site? Could be something changing up there or cist may have developed or gotten worse over time. Be careful if you are getting any weaker in arms or legs.

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