Back pain warning signs: when to get help fast

Most back pain isn't dangerous. Learn the rare warning signs, including cauda equina syndrome, that mean go to emergency now, and the signs that mean see your doctor soon.

5 min read · last reviewed October 1, 2026

Most back pain, even very painful back pain, is not dangerous. It gets better with time, movement and patience. But in a small number of people, back pain is a sign of something that needs fast medical care.

You don't need to worry about these every day. Just read this page once, share it with your family, and keep it in mind. Knowing the signs means you can act quickly if you ever need to.

Go to an emergency department now

These signs can mean the nerves at the bottom of your spine are being badly squeezed. This is called cauda equina syndrome. It is rare, but it is an emergency, because fast treatment can protect your bladder, bowel, sexual function and leg strength for life.

Go to an emergency department right away, at any time of day or night, if you have back pain or sciatica and:

• New trouble peeing: you find it hard to start, can't pee at all, or can't control when you pee, and this isn't normal for you.
• New bowel problems: you can't control your bowels, or don't notice when you need to poo.
• Numbness or tingling around your genitals, buttocks or anus. This is sometimes called "saddle numbness", because it affects the area that would touch a bicycle saddle. You might notice it when you wipe after using the toilet.
• Sciatica in both legs, or numbness or weakness in both legs that is severe or getting worse.
• New changes in sexual function, such as loss of feeling in your genitals.

Don't wait to see if it gets better, and don't wait for a regular appointment. Don't drive yourself. Ask someone to take you, or call 9-1-1 or your local emergency number. Tell the staff, "I have back pain and new bladder (or bowel) problems or numbness. I'm worried about cauda equina syndrome."

Call 9-1-1 or go to emergency

Also get emergency help if you have back pain:

• After a serious accident, such as a car crash or a fall from a height.
• With leg weakness that is quickly getting worse, such as your foot slapping on the ground, or your leg giving way.
• With chest pain, or with sudden, severe, tearing pain in your back or belly, especially if you feel faint. Rarely, this can be a problem with a major blood vessel (aorta).

See your doctor soon (the same day or within a day or two)

These signs don't always mean something serious, but they need to be checked. Call your doctor or clinic, or your local health line:

• Fever, chills or feeling generally unwell with back pain. This can rarely be a sign of infection in the spine.
• A history of cancer, especially breast, prostate, lung, kidney or thyroid cancer, and new back pain.
• Losing weight without trying.
• Pain that keeps getting worse, is constant, is worse at night or when lying down, and doesn't ease with rest or changing position.
• Back pain after a minor fall or lift if you have osteoporosis (thin bones), are older, or have taken steroid medicines for a long time. This can be a sign of a small fracture.
• A weakened immune system, for example from medicines or illness, or if you have injected drugs.
• Long morning stiffness, lasting more than 30 minutes, that gets better as you move, especially if your back pain started before age 45. This can be a sign of an inflammatory condition called axial spondyloarthritis.
• Numbness, tingling or weakness in one leg that isn't improving.

See your doctor in the next few weeks

• Your pain hasn't started to improve after 4 to 6 weeks of looking after it at home.
• Pain is stopping you from working, sleeping or doing everyday tasks.
• You feel low, anxious or stuck because of your pain.
• You aren't sure which pain medicine is safe for you.

What will the doctor do?

Your doctor will ask questions about your pain and your health, and examine your back and legs. They may test your strength, reflexes and feeling. If you have emergency signs, you will usually have an urgent MRI scan.

If there are no warning signs, you probably won't need a scan. That is good news, not a brush-off. It means your doctor is confident your back pain isn't caused by something serious.

A word about "making a fuss"

Some people worry about wasting a doctor's time, especially in the middle of the night. Please don't let that stop you. Cauda equina syndrome is rare, but the cost of waiting is high. Emergency teams would much rather check you and find nothing serious.

Something you can do today: Save this page on your phone, and tell a family member about the bladder, bowel and numbness warning signs.

Questions to ask your care team

• Which warning signs should I watch for, given my health history?
• If I notice bladder, bowel or numbness changes, where should I go?
• Does my medical history (such as cancer or osteoporosis) change what we should watch for?
• When should I come back if my pain isn't improving?
• Who can I call after hours?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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