Symptoms

Acute pain, or pain that is recent or sudden, that does not extend to the leg is most commonly caused by a sprain or muscle tear, usually occurring within 24 hours of heavy lifting or overuse of the back muscles. The pain is usually localized to the lower back, and there may be muscle spasms or soreness when the doctor touches the area. Usually this kind of pain is not serious and should go away after a few days. However, not all lower back pain is minor. A small number of cases are due to an underlying serious cause, such as a tumor, herniated disc, osteoporosis or other conditions. If your symptoms don't improve after 72 hours, see a doctor.

Here are some types of pain that require a visit with the doctor:

• Diffuse. Diffuse pain is spread over a large area and comes from deep tissue layers.

• Radicular. The pain is caused by irritation of a nerve root. Sciatica is an example of radicular pain. Sciatica is when a herniated or ruptured disc presses on the sciatic nerve, the large nerve that extends down the spinal column to its exit point in the pelvis and carries nerve fibers to the leg. In sciatica, you feel pain down into the leg, the pain travels below the knee and may involve the foot. You might have numbness and weakness of the lower leg muscles.

• Referred. The pain is actually elsewhere such as in the kidneys or lower abdomen.

Go to the emergency room if you have any of these symptoms:

• Loss of bowel or bladder function.
• Numbness of genitalia.
• Weakness such as foot drop.

This article was reviewed and updated June 2007.