Pain in the back, below the waist, that may be sudden and sharp or persistent and dull
- Age, gender, genetics, and lifestyle as risk factors depend on the cause
Lower back pain affects about 6 in 10 adults during the course of a year. More working days are lost due to back pain than to any other medical condition. In most cases, the pain lasts for only a week or so, but many people find that their problem recurs. In a minority of people, persistent lower back pain causes long-term disability.
Lower back pain is usually caused by minor damage to the ligaments and muscles in the back. The lower back is vulnerable to these problems because it supports most of the body’s weight and is under continual stress from movements such as bending and twisting. Less commonly, lower back pain may be a result of an underlying disorder such as a prolapsed or herniated disc in the spine.
What are the causes?
Lower back pain may come on suddenly (acute) or develop gradually over a period of weeks (chronic).
Acute back pain is often caused by a physical injury due to lifting heavy objects or to activities such as digging in the garden. The pain is commonly caused by a strained muscle or ligament. The injury may be aggravated by subsequent activity. In most cases, symptoms subside within 2–14 days.
Back pain that is more persistent may be improved by changing your posture, for example while sitting at a desk or driving a car. Pain may be aggravated by emotional stress and excessive muscle tension. Lower back pain may also occur during pregnancy, due both to changes in posture because of the extra weight of the baby and to softening of ligaments supporting the spine caused by hormonal changes.
Another cause of lower back pain is a prolapsed or herniated disc exerting pressure on a spinal nerve or the spinal cord. Back pain of this type may have a gradual or sudden onset and is accompanied by sciatica, in which severe shooting pain extends down the back of one or both legs.
Persistent lower back pain may be caused by joint disorders. In people over the age of 45, the most common joint problem is osteoarthritis, while in younger people the problem may be ankylosing spondylitis, which affects the joints of the spine. Less often, back pain results from bone disorders, such as Paget’s disease of the bone, or cancer that has spread to bone from a tumour elsewhere in the body (see Bone metastases).
In some cases, disorders affecting internal organs can lead to pain in the lower back. Examples include certain disorders of the female reproductive system, such as pelvic inflammatory disease, and of the urinary system, such as prostatitis.
What are the symptoms?
Pain in the lower back can take various forms. You may experience:
Sharp pain localized to a small area of the back.
More general, aching pain in the back and buttocks, which is made worse by sitting and relieved by standing.
Back stiffness and pain on bending.
Pain in the back that radiates to the buttock and leg, sometimes accompanied by numbness or tingling.
Back pain that is associated with weight loss or difficulty in controlling your bowel or bladder may be due to a serious underlying disorder. You should consult your doctor immediately if you develop any of these symptoms.
What can I do?
In most cases you should be able to treat lower back pain yourself by taking an over-the-counter painkiller. If the pain persists, additional relief may be provided by a heat pad or wrapped hot-water bottle and sometimes by an ice pack placed against your back. Try to continue your normal activities as much as possible but stop any activity that makes the pain worse.
If the pain is so severe that you cannot move, rest in bed for a day or two. However, you should start moving around as soon as possible, even if it initially causes some discomfort, and gradually resume normal activity. If the pain worsens or is still too severe to allow you to move after a few days, you should consult your doctor.
Once the pain has subsided, you can help to prevent recurrence if you pay attention to your posture, learn to lift correctly, and do regular exercises to strengthen the muscles of your back and make your spine more flexible (see Preventing back pain).
What might the doctor do?
If you need to consult your doctor because of severe or persistent lower back pain, he or she will probably carry out a physical examination to assess your posture, the range of movement in your spine, and any areas of local tenderness. Your reflexes, the strength of different leg muscles, and the sensation in your legs may also be tested to look for evidence of pressure on spinal nerves or the spinal cord. A pelvic or rectal examination may be necessary if you have symptoms that are associated with the female reproductive organs or with the bowels.
You may have various blood tests and X-rays to look for underlying causes of the pain, such as joint inflammation or bone cancer. If there is evidence of pressure on the spinal cord or spinal nerves, MRI or CT scanning may be carried out to detect abnormalities that require additional treatment, such as a prolapsed or herniated disc.
Unless there is a serious underlying cause for your back pain, your doctor will probably advise you to continue taking a painkilling drug. You may be given physiotherapy, osteopathy, or chiropractic to mobilize stiff and painful joints between the vertebrae. In some cases, an injection of a local anaesthetic with a corticosteroid (see Locally acting corticosteroids) is given directly into tender areas.
What is the prognosis?
Most episodes of lower back pain clear up without treatment, but the problem may recur. Improving posture and lifting techniques reduces the risk.
In a few cases, lower back pain may be a long-standing condition, severely disrupting work and social life and sometimes leading to depression. Effective pain control is essential and maintaining physical activity, despite some pain, reduces disability. People who become depressed because of their condition may benefit from treatment with antidepressants.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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