Reference
Autonomic dysreflexia, explained plainly.
It affects people with a spinal cord injury at about T6 or above, it comes on suddenly, and its most common trigger is a full bladder. Knowing the signs means being able to respond correctly within minutes — and that is what this page is for.
In one sentence, up front: a pounding headache plus sweating above the level of injury in someone with a high spinal cord injury means: sit upright, loosen anything tight, check the bladder — and if it does not improve quickly, call emergency services. Everything else below, calmly.
What happens in the body
Below the level of injury, the body reports a strong stimulus — a stretched bladder, a full bowel, a wound. Normally the brain would receive that message and regulate the blood pressure. With a spinal cord injury at about T6 or above, the message no longer gets through. The nervous system below the injury reacts anyway: it narrows the blood vessels, and blood pressure climbs steeply.
The body above the injury tries to compensate — hence the sweating, the flushing, the pounding headache and often a strikingly slow pulse. The rise in blood pressure is the real risk: left unaddressed, it can become dangerously high. That is why autonomic dysreflexia counts as an emergency, and why the most important step is finding and removing the trigger.
Orientation
How to recognise it.
Not all signs appear together every time. Typical is the combination of headache and signs above the level of injury.
| Sign | What matters |
|---|---|
| Pounding headache | The leading symptom — sudden, often severe, throbbing with the pulse |
| Sweating and flushing above the injury level | Face, neck and shoulders; below the level, the skin often stays pale and cool |
| Goosebumps | Often below the injury level — an early, easily missed sign |
| Feeling hot, blocked nose | Sounds trivial, but belongs to the typical picture |
| Strikingly slow pulse | Unlike most emergencies — high pressure with a slow heartbeat |
| Restlessness, anxiety, blurred vision | Signs that blood pressure is significantly elevated |
If you have a blood pressure monitor: with a high spinal cord injury, resting blood pressure is often lower than in non-injured people. A reading that would be "still normal" for others can already be a marked rise here. Knowing your own baseline is worth a great deal.
The most common triggers
First, by a wide margin, comes the bladder: too full because a catheterisation is overdue, or a catheter that is kinked or blocked. Next comes the bowel — a full rectum or hard stool. And finally everything that irritates below the level of injury without being felt: clothing or shoes that are too tight, a pinched tube, pressure sores and wounds, an ingrown toenail, and for women also menstrual pain.
That order is also the search order in an emergency: bladder first, then bowel, then skin and clothing.
What to do immediately
The steps are simple and often work within minutes — in this order:
- Sit upright, legs down. The upright position helps lower blood pressure. Do not lie down.
- Loosen anything tight — belt, waistband, compression stockings, abdominal binder, tight shoes.
- Empty the bladder or check the catheter: kinked, blocked, bag full? That removes the most common trigger.
- Look for other triggers: bowel, skin, sitting position, pinched objects.
- If it does not improve quickly — or blood pressure stays high, the headache worsens, vision blurs or confusion sets in: call emergency services and say the words "autonomic dysreflexia".
The same scheme applies for family and friends — sit them up, loosen anything tight, bladder first. Anyone close to a person with a high spinal cord injury should have read these five steps once before they are needed.
A note for when you are out and about: many people carry an emergency card noting autonomic dysreflexia — for paramedics and before operations this information matters, because blood pressure spikes have to be interpreted differently there.
Why keeping a record helps
After an episode, the questions are always the same: when was it, what was the trigger, how high did the pressure go? A few noted episodes with time and suspected trigger reveal patterns — for instance, that it happens whenever the catheter interval was stretched. That is exactly the information your care team needs to adjust interval or supplies.
In the Bladder & Bowel Manager, autonomic signs such as goosebumps, sweating or headache can be logged with one tap on an entry, optionally with a blood pressure reading. If such signs are logged without an accompanying emptying, the app reminds you to think of the bladder as the most common trigger. It does not replace a diagnosis or an emergency decision.