What are the warning signs of autonomic dysreflexia?

A sudden, severe pounding headache; sweating and flushing or blotchy red skin above the injury; goosebumps; a blocked nose; blurred vision; a slow heart rate; and anxiety. The skin below the injury may be pale and clammy. A “silent” form can raise blood pressure dangerously with few symptoms.

What should I do if someone has autonomic dysreflexia?

Act in order: first sit the person upright (never lie them flat); second, loosen or remove anything tight; third, check the bladder first (catheter kinks, full leg bag, drainage); then the bowel; then the skin and other triggers. If it does not settle quickly, or you cannot find the trigger, call 995 immediately.

Why is autonomic dysreflexia dangerous?

If untreated, the very high blood pressure can cause seizures, a stroke, bleeding in the eye, heart problems or death, so it must never be ignored or “waited out.” Call 995 if an episode does not quickly resolve. Preventing episodes – through good bladder, bowel and skin care – is equally important, and seek review after any episode as it can recur.

Autonomic Dysreflexia: A Spinal Cord Injury Emergency (Singapore)

Written & reviewed by the BestDoctors.sg editorial team · Last updated 29 Aug 2026 · General information, not medical advice

Quick answer. Autonomic dysreflexia is a sudden, potentially life-threatening rise in blood pressure that is unique to spinal cord injury, mainly affecting people injured at or above the mid-back (around T6). It is triggered by something painful or irritating below the injury – most often a full bladder or bowel – that the person often cannot feel. Warning signs include a pounding headache and sweating and flushing above the injury. The response, in order, is: sit the person upright, loosen tight clothing, then find and remove the trigger – bladder first, then bowel, then skin. If it does not settle quickly, call 995. It is a medical emergency.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

What autonomic dysreflexia is

Autonomic dysreflexia is a sudden, dangerous reflex reaction unique to spinal cord injury. Something painful or irritating below the level of injury – which the person often cannot feel – triggers a sharp rise in blood pressure above the person’s usual level, along with other symptoms. Because the blood pressure can climb high enough to be life-threatening, it is a medical emergency that everyone at risk, and their families and carers, should understand. Knowing what it is, how to recognise it and exactly what to do can genuinely save a life, which is why it is one of the most important things to learn after a higher-level spinal cord injury.

Who is at risk

Autonomic dysreflexia mainly affects people with a spinal cord injury at or above the mid-back, around the level known as T6, though it can occasionally occur with injuries a little lower. If your injury is at this level or above, you and everyone who supports you should be familiar with the warning signs and the response. It is worth carrying an alert card or an action plan from your team, because many general healthcare staff are unfamiliar with autonomic dysreflexia, and being able to tell them clearly what is happening can speed up the right treatment in an emergency.

Warning signs to recognise

The warning signs come on suddenly. They include a severe, pounding or throbbing headache; sweating and flushing, or blotchy red skin, above the level of injury, on the face, neck and chest; goosebumps; a blocked or stuffy nose; blurred vision or spots; a slow heart rate; and a feeling of anxiety or unease. The skin below the injury may be pale, cold and clammy. Importantly, there is also a “silent” form, in which blood pressure is dangerously high but there are few or no symptoms – which is one reason people at risk are taught to monitor and act on triggers even when they feel well.

The first-aid steps, in order

If autonomic dysreflexia is suspected, act quickly and in this order. First, sit the person upright, with the head up and the legs lowered, which helps bring the blood pressure down – never lie them flat. Second, loosen or remove anything tight or constricting – clothing, an abdominal binder, leg-bag straps, stockings or shoes. Third, look for and remove the trigger, checking the bladder first, as it is the most common cause: check the catheter for kinks, twists or a full or closed leg bag, and make sure urine is draining; a full bladder must be emptied. Doing these steps promptly resolves many episodes.

If it does not settle

If sitting upright, loosening clothing and dealing with the bladder do not resolve it, check the bowel for constipation or impaction, and then check the skin and other triggers below the injury, such as a pressure sore, an ingrown toenail, tight or wrinkled clothing, or extreme temperature. Keep monitoring until the symptoms and blood pressure settle. If the person has an action plan or prescribed medication from their team, follow it. But if symptoms or the high blood pressure do not settle quickly, or you cannot find the trigger, call 995 immediately – do not wait it out, because untreated autonomic dysreflexia is dangerous.

The common triggers

Almost anything that would normally be felt as pain or discomfort below the injury can trigger autonomic dysreflexia, even though the person cannot feel it. In order of likelihood, the bladder is the most common source – a full bladder, a blocked or kinked catheter, a urinary infection or a bladder stone. The bowel comes next, with constipation or impaction. Then come skin and other causes: a pressure sore, an ingrown toenail, tight clothing, extremes of temperature, sexual activity, menstruation or a fracture. Knowing these triggers helps you both prevent episodes, by keeping on top of bladder and bowel care, and find the cause quickly when one occurs.

Why it must not be ignored

Autonomic dysreflexia is not something to wait out or treat casually. If untreated, the very high blood pressure can cause seizures, a stroke, bleeding in the eye, heart problems or, in the worst cases, death. This is why the emergency response and the call to 995 matter so much when an episode does not quickly resolve. Prevention is equally important: keeping the bladder emptied and the catheter flowing, maintaining a good bowel routine, and protecting the skin all reduce the risk of an episode in the first place. Take every episode seriously, and seek review afterwards, as it can recur.

Getting help and being prepared

Being prepared is the best protection. Make sure you and everyone who cares for you know the warning signs and the ordered first-aid steps, keep an alert card or action plan to hand, and know how to reach your team. In Singapore, the Tan Tock Seng Hospital Rehabilitation Centre and hospital spinal, rehabilitation and urology teams can help you and your carers learn to manage autonomic dysreflexia, and community nurses can support you at home. In an emergency, call 995, and tell the responders the person has a spinal cord injury and this is autonomic dysreflexia, so they can act on it quickly.

Sources

MSKTC – Autonomic dysreflexia and spinal cord injury: msktc.org
Christopher & Dana Reeve Foundation – Autonomic dysreflexia: christopherreeve.org
Spinal Injuries Association – Autonomic dysreflexia: spinal.co.uk

General information only. This guide supports, but does not replace, advice from your own doctor and spinal injury care team. Learn to recognise autonomic dysreflexia if your injury is at the upper level (around the mid-back and above): a sudden pounding headache, sweating or flushing above the injury, a blocked nose or a slow pulse can mean a dangerous rise in blood pressure. Sit upright straight away, loosen anything tight, and look for and remove the cause – most often a full bladder (check the catheter for kinks) or a full bowel. Call 995 if it does not settle quickly, as it is a medical emergency. Check your skin every day and act on any red or broken area. If you are struggling emotionally, you are not alone: the Samaritans of Singapore (SOS) are on 1767 and mindline.sg on 1771.

Autonomic Dysreflexia & Spinal Cord Injury