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
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
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
- 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
- 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
- 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
- Deep vein thrombosis (blood clot in vien or artery)
- Detrusor-sphincter dyssynergia
- Epididymitis or scrotal compression
- Gall, bladder or kidney stones
- Gastric ulcers or gastritis
- Gastrocolic irritation
- Heterotopic bone
- Ingrown toenail
- Insect bites
- Invasive testing
- 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
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.
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.
- 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.