Low back pain
What are the common causes?
Low back pain can be caused by a number of factors from injuries to the effects of
aging.
Low Back Sprain and Strain - The muscles of the low back provide power and
strength for activities such as standing, walking and lifting. A strain of the muscle can
occur when the muscle is poorly conditioned or overworked. The ligaments of the low back
act to interconnect the five vertebral bones and provide support or stability for the low
back. A sprain of the low back can occur when a sudden, forceful movement injures a
ligament which has become stiff or weak through poor conditioning or overuse.
These injuries, or sprain and strain, are the most common causes of low back pain.
Frequently, a combination of other factors may increase the likelihood of injury or
disease:
- poor conditioning
- improper use
- obesity
- smoking
The natural effects of normal aging on the body, in general, and low back, in
particular, are osteoporosis or decreased amount of bone; decrease in strength and
elasticity of muscles; and decrease in elasticity and strength of ligaments. Although you
cannot totally halt the progress of these effects, they can be slowed by regular exercise,
knowing the proper way to lift and move objects, proper nutrition, and avoidance of
smoking.
Age - "Wear and tear" and inherited factors will cause degenerative
changes in the disks, called degenerative disk disease, and arthritic changes in the small
joints. These changes occur to some degree in everyone. When severe, they can cause low
back stiffness and pain. Arthritic bone spurs and inflamed joints can cause nerve
irritation and leg pain. Almost everyone develops "wear and tear" changes in
their low back as they age, although for most people it causes little pain or loss of
function.
Osteoporosis and Fractures - All bones lose bone strength over time and the
lumbar vertebrae, particularly in postmenopausal women, can be fractured or compressed
from a fall or even from the stress of lifting or everyday activities.
| Protruding Disk - The disk is composed of a soft center or
nucleus, which, in children and young adults, is jelly-like. The nucleus is surrounded by
a tougher outer portion called the anulus. With normal aging, the nucleus begins to
resemble the anulus. During middle-age, fissures or cracks may occur in the disk. These
may be the source of back pain. If the crack extends out of the disk, material from the
disk may push out or rupture. This often is referred to as a herniated or slipped disk. If
the protruded disk presses a nerve, it may cause pain in the leg. |
Definition of Low back pain
Low back pain is a common musculoskeletal symptom that may be either acute or chronic.
It may be caused by a variety of diseases and disorders that affect the lumbar spine. Low
back pain is often accompanied by sciatica, which is pain that involves the sciatic nerve
and is felt in the lower back, the buttocks, and the backs of the thighs.
Description of Low back pain
Low back pain is a symptom that affects 80% of the general United States population at
some point in life with sufficient severity to cause absence from work. It is the second
most common reason for visits to primary care doctors, and is estimated to cost the
American economy $75 billion every year.
Low back pain may be experienced in several different ways:
- Localized. In localized pain the patient will feel soreness or discomfort when the
doctor palpates, or presses on, a specific surface area of the lower back.
- Diffuse. Diffuse pain is spread over a larger 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.
- Referred. The pain is perceived in the lower back but is caused by inflammation
elsewhere-- often in the kidneys or lower abdomen.
Causes & Symptoms of Low back pain
Acute pain
Acute pain in the lower back 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, and there may be muscle spasms or
soreness when the doctor touches the area. The patient usually feels better when resting.
Chronic pain
Chronic low back pain has several different possible causes:
Mechanical
Chronic strain on the muscles of the lower back may be caused by obesity; pregnancy; or
job-related stooping, bending, or other stressful postures.
Malignancy
Low back pain at night that is not relieved by lying down may be caused by a tumor in
the cauda equina (the roots of the spinal nerves controlling sensation in and movement of
the legs), or a cancer that has spread to the spine from the prostate, breasts, or lungs.
The risk factors for the spread of cancer to the lower back include a history of smoking,
sudden weight loss, and age over 50.
Ankylosing spondylitis
Ankylosing spondylitis is a form of arthritis that causes chronic pain in the lower
back. The pain is made worse by sitting or lying down and improves when the patient gets
up. It is most commonly seen in males between 16 and 35. Ankylosing spondylitis is often
confused with mechanical back pain in its early stages.
Herniated spinal disk
Disk herniation is a disorder in which a spinal disk begins to bulge outward between
the vertebrae. Herniated or ruptured disks are a common cause of chronic low back pain in
adults.
Psychogenic
Back pain that is out of proportion to a minor injury, or that is unusually prolonged,
may be associated with a somatoform disorder or other psychiatric disturbance.
Low back pain with leg involvement
Low back pain that radiates down the leg usually indicates involvement of the sciatic
nerve. The nerve can be pinched or irritated by herniated disks, tumors of the cauda
equina, abscesses in the space between the spinal cord and its covering, spinal stenosis,
and compression fractures. Some patients experience numbness or weakness of the legs as
well as pain.
Diagnosis
The diagnosis of low back pain can be complicated. Most cases are initially evaluated
by primary care physicians rather than by specialists.
Initial workup
Patient history
The doctor will ask the patient specific questions about the location of the pain, its
characteristics, its onset, and the body positions or activities that make it better or
worse. If the doctor suspects that the pain is referred from other organs, he or she will
ask about a history of diabetes, peptic ulcers, kidney stones, urinary tract infections,
or heart murmurs.
Physical examination
The doctor will examine the patient's back and hips to check for conditions that
require surgery or emergency treatment. The examination includes several tests that
involve moving the patient's legs in specific positions to test for nerve root irritation
or disk herniation. The flexibility of the lumbar vertebrae may be measured to rule out
ankylosing spondylitis.
Imaging studies
Imaging studies are not usually performed on patients whose history and physical
examination suggest routine muscle strain or overuse. X rays are ordered for patients
whose symptoms suggest cancer, infection, inflammation, pelvic or abdominal disease, or
bone fractures. MRIs are usually ordered only for patients with certain types of masses or
tumors.
It is important to know that the appearance of some abnormalities on imaging studies of
the lower back does not necessarily indicate that they cause the pain. Many patients have
minor deformities that do not create symptoms. The doctor must compare the results of
imaging studies very carefully with information from the patient's history and physical
examination.
Treatment
All forms of treatment of low back pain are aimed either at symptom relief or to
prevent interference with the processes of healing. None of these methods appear to speed
up healing.
Acute pain
Acute back pain is treated with nonsteroidal anti-inflammatory drugs (NSAIDs), such as
ibuprofen, muscle relaxants, or aspirin. Applications of heat or cold compresses are also
helpful to most patients. If the patient has not experienced some improvement after
several weeks of treatment, the doctor will reinvestigate the cause of the pain.
Chronic pain
Patients with chronic back pain are treated witha combination of medications, physical
therapy, andoccupational or lifestyle modification. The medicationsgiven are usually
NSAIDs, although patients withhypertension, kidney problems, or stomach ulcers should not
take these drugs. Patients who take NSAIDs for longer than six weeks should be monitored
periodically for complications.
Physical therapy for chronic low back pain usually includes regular exercise for
fitness and flexibility, and massage or application of heat if necessary.
Lifestyle modifications include giving up smoking, weight reduction (if necessary), and
evaluation of the patient's occupation or other customary activities.
Patients with herniated disks are treated surgically if the pain does not respond to
medication.
Patients with chronic low back pain sometimesbenefit from pain management techniques,
including biofeedback, acupuncture, and chiropractic manipulation of the spine.
Psychotherapy is recommended for patients whose back pain is associated with a
somatoform, anxiety, or depressive disorder.
Low back pain with leg involvement
Treatment of sciatica and other disorders that involve the legs may include NSAIDs.
Patients with long-standing sciatica or spinal stenosis that do not respond to NSAIDs are
treated surgically. Although some doctors use cortisone injections to relieve the pain,
this form of treatment is still debated.
Alternative treatment
A thorough differential diagnosis is important before any treatment is considered.
There are times when alternative therapies are the most beneficial, and other times when
more invasive treatments are needed.
Chiropractic
Chiropractic treats patients by manipulating or adjusting sections of the spine. It is
one of the most popular forms of alternative treatment in the United States for relief of
back pain caused by straining or lifting injuries. Some osteopathic physicians, physical
therapists, and naturopathic physicians also use spinal manipulation to treat patients
with low back pain.
Traditional Chinese medicine
Practitioners of traditional Chinese medicine treat low back pain with acupuncture, tui
na (push-and-rub) massage, and the application of herbal poultices.
Herbal medicine
Herbal medicine can utilize a variety of antispasmodic herbs in combination to help
relieve low back pain due to spasm. Lobelia (Lobelia inflata) and myrrh (Commiphora
molmol) are two examples of antispasmodic herbs.
Homeopathy
Homeopathic treatment for acute back pain consists of applications of Arnica oil
to the sore area or oral doses of Arnica or Rhus toxicodendron. Bellis
perennis is recommended for deep muscle injuries. Other remedies may be recommended
based on the symptoms presented by the patient.
Body work and yoga
Massage and the numerous other body work techniques can be very effective in treating
low back pain. Yoga, practiced regularly and done properly, can be most useful in
preventing future episodes of low back pain.
Prognosis
The prognosis for most patients with acute low back pain is excellent. About 80% of
patients recover completely in 4-6 weeks. The prognosis for recovery from chronic pain
depends on the underlying cause
Prevention
Low back pain due to muscle strain can be prevented by lifestyle choices, including
regular physical exercise and weight control, avoiding smoking, and learning the proper
techniques for lifting and moving heavy objects. Exercises designed to strengthen the
muscles of the lower back, and chairs or car seats with lumbar supports are also
recommended. |
