Low back pain: when to worry and when not to

Back pain is the most common complaint in rehabilitation clinics, by a wide margin. And the first thing I tell worried patients is this: in most cases, it is not serious. But there are specific warning signs that change that picture completely. Here I explain what they are, so you can tell the difference between waiting calmly and acting quickly.

What almost nobody tells you about low back pain

Low back pain has a bad reputation, but the science is quite optimistic: 85% of episodes improve on their own within a few weeks, especially when people stay active and avoid complete rest. The problem is not the pain itself — it is not knowing when something more serious is behind it.

That is why I never say "it is just muscle" without examining the patient first. Specific causes need to be ruled out before reassuring anyone.

Red flags: these need urgent attention

These are the warning signs that, if they appear, mean you should seek help immediately — do not wait:

• Loss of bladder or bowel control. This can indicate compression of the nerves that control those functions (cauda equina syndrome). This is a medical emergency.
• Weakness or numbness in the leg that is getting worse. If it spreads or worsens rapidly, do not wait.
• Pain following a significant fall or impact. A fracture must be ruled out, especially in older adults.
• Severe night pain that wakes you up. Not the kind that shifts when you change position, but pain that does not ease at all. This can indicate infection or a tumour.
• Fever alongside low back pain. Possible disc or vertebral infection.
• History of cancer. Back pain in someone with an oncological history needs to be ruled out quickly.
• Unexplained weight loss over the past few weeks.

If you have any of these signs, go to A&E or ask for a priority appointment. Do not delay.

When to book an appointment (not urgent, but do not ignore it)

Some situations are not emergencies, but they do deserve assessment:

• The pain has lasted more than six weeks without clear improvement.
• It keeps coming back — episodes that return every few months.
• The pain travels down the leg (towards the buttock, thigh or even the foot). This could be radiculopathy or sciatica that needs proper evaluation.
• It is affecting your work, sleep or daily activities.
• You do not know what caused it and you have not had a clear diagnosis yet.

What I can do as a rehabilitation doctor

My advantage is that I assess and treat in the same appointment. With musculoskeletal ultrasound I can see in real time what is happening — the discs, the facet joints, the soft tissues — without waiting weeks for an MRI.

Depending on what we find, treatment may include:

• Lumbar facet joint blocks — for pain coming from the spinal joints, very common in people over 50.
• Ultrasound-guided injections — anti-inflammatory or corticosteroid delivered precisely to the right spot.
• Nerve blocks — when pain radiates down the leg and there is an irritated nerve to address.
• Exercise and rehabilitation plan — coordinated with your physiotherapist, which is the essential step for lasting results.

The goal is not only to relieve the pain now. It is to understand what is causing it, treat it properly, and prevent it from coming back.

Frequently asked questions

How long is it normal to have low back pain? +

Most episodes of non-specific low back pain improve within two to three weeks. If it persists beyond six weeks without improvement, or if it disrupts your work or sleep, it deserves a medical assessment even without any red-flag symptoms.

Do I need an MRI scan? +

Not always. In most cases of low back pain without red flags, an MRI does not change the initial treatment and can create more anxiety than useful information. Your doctor will decide whether imaging is needed after examining you.

Does pain going down my leg always mean a herniated disc? +

Not necessarily. Several structures can irritate the nerve and cause radiating pain: discs, facet joints, muscles. Ultrasound and clinical examination help to tell them apart without imaging in every case.

Should I stop exercising? +

In most cases, no. Controlled movement is part of the treatment, not the enemy. What does need adjusting is the intensity and type of activity depending on the phase. I will guide you in the consultation on what you can do and what to temporarily avoid.