Cauda equina syndrome

Also called CES, Cauda equina compression

The one back problem measured in hours. Saddle numbness, bladder or bowel changes, or new weakness in both legs is a 999 or A and E matter tonight.

What it is

The spinal cord ends around the top of the lower back. Below that it continues as a bundle of nerve roots named, for its appearance, the horse's tail: the cauda equina. Those roots carry the nerves for the bladder, the bowel, the sexual organs, the saddle area and the legs.

Cauda equina syndrome is those roots being compressed, most often by a large disc prolapse, sometimes by a tumour, an infection or a bleed. It is rare, in the region of one or two people in every hundred thousand each year, and it is the reason every honest article about back pain carries a warning.

Compression damages nerves by starving them. Decompression surgery within hours of the first bladder symptoms gives a far better chance of continence and sexual function than surgery a day later, and that difference does not come back. This is the whole reason the entry exists: nearly everything about back pain is reassuring, and this is the exception that is not.

Most people who go to hospital worried about cauda equina do not have it. That is the correct outcome. A service that never sees a false alarm is a service seeing people too late.

Signs you might notice

Numbness or altered sensation in the saddle area: the parts that would touch a saddle, including the genitals, the inner thighs and around the back passage. Noticing that toilet paper feels different is a real and commonly missed sign.

Difficulty starting to pass urine, a weak stream, not feeling the bladder fill, not feeling urine pass, or leaking without knowing.

Loss of control of the bowel, or not being able to feel a bowel movement coming.

New weakness or numbness in both legs, or pain in both legs rather than one.

Loss of sensation during sex, or new erectile difficulty alongside any of the above.

Severe back pain is often present and sometimes is not. Absence of terrible pain does not rule this out.

How it can affect day-to-day life

The reason this is written for carers as well as patients is that several of the earliest signs are private, embarrassing, and easy to explain away. People delay because they do not want to make a fuss about their bladder, or because they assume the numbness is from sitting awkwardly.

Someone with a learning disability, a communication difference or dementia may not report saddle numbness at all. Change in continence in a person who was previously continent, alongside back pain or new leg weakness, is the signal, and it deserves the same urgency as the words would.

After treatment, some people recover completely. Others live with lasting bladder, bowel or sexual difficulty and altered sensation, and the support that matters then is continence care, specialist physiotherapy and psychological support, not further scans.

Supporting someone well

Learn the red flags and say them out loud to the person, in plain words. "If you cannot feel yourself wee, or the toilet paper feels different, we go to hospital tonight" is more useful than a leaflet.

Go to A and E, or call 999 if they cannot travel. Do not wait for a GP appointment, do not wait until morning, and do not accept a routine referral for these symptoms.

Say the words cauda equina at reception and at triage. It changes the pathway. Ask for an emergency MRI.

Take a note of when each symptom started. The timeline is what the surgical decision turns on, and nobody remembers it accurately under pressure.

If symptoms are dismissed and they fit the list above, ask directly for the scan and for a second opinion. Being wrong about this costs an evening; being ignored about it costs a lifetime.

Do not be reassured by a scan taken before the symptoms began.

Where to get help

A and E immediately, or 999 if the person cannot get there. This is one of the few entries in this library where the answer is not a GP.

Afterwards: a spinal team, a continence service, physiotherapy, and specialist psychological support. Ask for referral rather than waiting to be offered it.

NICE guideline NG59 sets out the emergency assessment expected in the NHS, and is worth quoting if you meet resistance.