Cauda Equina Syndrome: The Red Flags Patients Need to Know

Most episodes of lower back pain and sciatica are not emergencies and will improve with appropriate treatment. However, there is a rare but serious condition called cauda equina syndrome (CES) that requires urgent medical assessment.

Knowing the warning signs can help you recognise when back pain or sciatica needs immediate attention.

What is cauda equina syndrome?

The cauda equina is a bundle of nerves at the lower end of the spinal cord. These nerves supply the legs, bladder, bowel and areas around the pelvis.

Cauda equina syndrome occurs when these nerves become significantly compressed or disrupted. One of the more common causes is a large disc prolapse, although other conditions can also cause compression.

Because prolonged nerve compression can potentially result in permanent problems, CES is a medical emergency.

What are the red flags?

Seek urgent medical assessment if you develop new or worsening symptoms such as:

🚨 Changes to bladder function

• Difficulty starting to urinate

• Being unable to urinate

• Loss of awareness that your bladder is full

• New urinary leakage associated with altered sensation

🚨 Changes to bowel function

• New loss of bowel control

• Difficulty controlling your bowels

🚨 Altered sensation around the saddle area

New numbness, tingling or reduced sensation around the genitals, anus, buttocks or inner thighs — sometimes described as "saddle numbness".

🚨 Significant changes in the legs

New or rapidly worsening weakness in one or both legs, particularly if associated with changes in bladder, bowel or saddle sensation.

What should you do?

If you develop new bladder or bowel dysfunction, saddle numbness or significant/progressive leg weakness, don't wait for your next routine osteopathy, physiotherapy or GP appointment.

You should seek urgent medical assessment, usually through an emergency department or by contacting NHS 111 for immediate advice. If symptoms are severe or rapidly worsening, call 999.

Importantly, back pain or sciatica alone does not mean you have cauda equina syndrome. These symptoms are extremely common and usually have a much less serious cause. It is the development of the specific neurological warning signs above that makes urgent assessment particularly important.

Why early assessment matters

If cauda equina syndrome is suspected, clinicians may arrange urgent investigations such as an MRI scan and, where appropriate, specialist surgical assessment.