Low back pain

This is the most common type. About 19 in 20 cases of acute (sudden onset) low back pain are classed as 'simple low back pain'.

Simple low back pain means that the pain is not due to any underlying disease that can be found. In some cases the cause may be a sprain (an over-stretch) of a ligament or muscle. In other cases the cause may be a minor problem with a disc between two vertebrae, or a minor problem with a small 'facet' joint between two vertebrae. Sometimes a pain may develop immediately after you lift something heavy, or after an awkward twisting movement. Sometimes you can just wake up with low back pain.

Simple does not mean that the pain is mild - the pain can range from mild to very bad. Typically, the pain is in one area of the lower back, but sometimes it spreads to the buttocks or thighs. The pain is usually eased by lying down flat, and is often made worse if you move your back, cough, or sneeze. So, simple back pain is 'mechanical' in the sense that it varies with posture or activity.

Most bouts of simple low back pain improve quickly, usually within a week or so. In about 3 in 4 cases, the pain has either gone or has greatly eased within four weeks. In about 9 in 10 cases the pain has gone or has greatly eased within six weeks.

Nerve root pain
This occurs in less than 1 in 20 cases. This means that a nerve coming from the spinal cord is irritated or pressed on. (This is often referred to as a 'trapped nerve'.) You feel pain along the course of the nerve. Therefore, you may feel pain down a leg to the calf or foot, and the pain in the leg or foot is often worse than the pain in the back. A common example is 'sciatica'. This is where a main nerve to the leg, the sciatic nerve, is irritated or pressed on.

Nerve root pain can range in severity from mild to very bad. Like with simple low back pain, nerve root pain is often eased by lying down flat, and is often made worse if you move your back, cough, or sneeze. The irritation or pressure on the nerve may also cause pins and needles, numbness or weakness in part of a buttock, leg or foot.

What to do

Most cases of low back pain that develop suddenly (acutely) are due to simple low back pain. Many people just 'get on with it' and treat it themselves - and indeed most get better quickly. However, if in doubt, see your doctor for a check-over and advice.

As a general guide, if any of the following occur then it may indicate that it may not be simple low back pain.   Therefore, tell a doctor if you have any of the following.

The pain first develops under the age of 20 years or over the age of 55 years.

• Constant back pain that is not eased by lying down or resting.
• Pain travels to the chest, or is higher in the back behind the chest.
• If the pain developed gradually, and slowly gets worse and worse over days or weeks. (Most cases of simple low back pain occur acutely, that is, suddenly.)
• In addition to back pain, you have:
• Weakness of any muscles in a leg or foot.
• Numbness (lack of feeling) in part or parts of a buttock, around the anus, or in a leg or foot.
• Problems with your bladder or bowels such as not being able to pass urine or loss of control (incontinence).
• Weight loss, fever, or if you feel generally unwell.
• Recent history of violent trauma or injury to the back.
• You have or have had a cancer of any part of the body.
• You have taken steroid tablets for more than a few months.
• If you have a poor immune system. For example, if you are on chemotherapy or have HIV/AIDS.
• If you are unsure about any symptom.

Cauda equina syndrome is a particularly serious type of nerve root problem. This is a rare disorder where the nerves at the very bottom of the spinal cord are pressed on. This syndrome can cause low back pain plus:

• problems with bowel and bladder function (usually unable to pass urine),
• numbness in the 'saddle' area (around the back passage - anus),
• weakness in one or both legs.

This syndrome needs urgent treatment to preserve the nerves to the bladder and bowel from becoming permanently damaged. DO NOT IGNORE SUCH SYMPTOMS. Seek advice promptly from your own doctor or NHS Direct.