Low back pain usually involves spasms of the large, supportive muscles alongside the spine. Any injury to the back may produce muscle spasms and stiffness.

Pain caused by muscular strain is usually confined to the back. Occasionally, it may radiate into the buttocks or upper leg(s).

The onset of pain may be immediate or may occur a few hours after the exertion or injury. Many times the cause is not obvious.

Most back problems will get better on their own.

• Muscle strain, pulled muscle in the back or similar injury (the most common cause)
• Muscle aches related to a viral infection
• Menstruation or premenstrual syndrome (PMS)
• Prolonged sitting in a person who is susceptible to back problems
• Arthritis
• Poor posture
• Nonspecific back pain

In children, causes of back pain include the following:

• Scoliosis
• Scheuermann's kyphosis
• Spondylolysis

• Bladder infection
• Endometriosis
• Ovarian cancer
• Ovarian cysts
• Pressure on a nerve root (for example, spinal stenosis or herniated nucleus pulposus)
• Ruptured vertebral disk

Low back pain can create a vicious cycle in which a muscle spasm causes pain, then the pain brings additional muscle spasms. Rest and pain medication can help interrupt this cycle. Anti-inflammatory medications such as aspirin or ibruprofen should be continued as long as there is significant pain.

To avoid an upset stomach, take the medication with food unless otherwise instructed. No medication will speed up the healing -- drugs can only help eliminate the symptoms. Sometimes heat or ice applied to the affected area may provide some relief.

An injury must heal by itself. Try to avoid reinjury during the healing process. Rest flat on your back for the first 24 hours and be very careful when moving around.

Severe muscle spasm pain usually lasts for 2 to 3 days and may be followed by weeks of less severe pain.

Strenuous activity during the six weeks following an injury can bring the problem back and postpone complete recovery. After healing, a conservative exercise program will help prevent reinjury.

It is helpful to sleep on a very firm mattress (with a bed board under the mattress), on a waterbed, or even on the floor.

A folded towel beneath the low back and a pillow under the knees may make you more comfortable while sleeping.

You should contact your health care provider if any of the following occur:

• You have significant pain that persists beyond a week.
• You have an associated, unexplained fever.
• There is redness or swelling on the back or spine.
• The pain travels down the legs below the knee (which suggests pressure on the nerves as they leave the spinal cord).
• The back pain is the result of a severe blow or fall.
• The back pain is caused by an injury received at work--examination by a doctor is required by the workers' compensation laws.
• You have weakness or numbness in a leg.

Your health care provider will obtain your medical history and will perform a physical examination.

Medical history questions documenting low back pain may include the following:

• Location: Is the pain on one side only (unilateral)?
• Quality
  • Is it severe?
  • Is the pain located behind the thigh and down the inside of the leg (sciatic pain)?
  • Is the pain NOT located behind the thigh and down the inside of the leg (nonsciatic pain)?
• Time pattern
  • Does the pain occur only at night (nocturnal)?
  • Did the pain begin suddenly?
  • Is the pain persistent?
  • Did the pain begin recently?
  • When did the pain begin (at what age did you first experience back pain)?
  • Has the pain been long-standing (chronic)?
  • How long does each episode last?
  • Does the pain occur repeatedly (recurrent)?
  • How often does back pain occur?
• Radiation
  • Does the pain go into the hip, leg or feet (lower extremity)?
  • Is the pain radiating down only one side of the body?
• Aggravating factors
  • Is the pain worse when coughing?
  • Does the pain get worse with straining, lifting, or similar activities?
• Relieving factors: Does exercise relieve the pain?
• What other symptoms are also present?

Physical examination will likely focus on the back, the abdomen, and the extremities, with special attention to testing the nerve function of the legs.

If the history and physical examination indicate damage to the nerves leaving the spinal cord, a myelogram (an X-ray or CT scan of the spine after dye has been injected into the spinal column) may be necessary. Other possible tests include a CT of lumbosacral spine or MRI of lumbosacral spine.

Hospitalization, traction, or surgery should only be considered if nerve damage is present or the condition fails to heal for a prolonged period.