Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a condition that develops when the area that contains certain nerves in the wrist becomes inflamed and swollen. Carpal tunnel syndrome causes compression of the median nerve at the wrist.


Causes/associated factors
Carpal tunnel syndrome can be caused by any condition that crowds the carpal tunnel -- a U-shaped cluster of eight small wrist bones (the carpal bones) aligned in two rows of four bones each and overlaid by a wrist-supporting ligament (the transverse carpal ligament). The median nerve, flexor tendons of the hand and blood vessels pass through the carpal tunnel.
The median nerve supplies sensation to your thumb, index finger, middle finger and usually half of your fourth finger (ring finger). It also provides nerve input to muscles of the thumb area. The nearby flexor tendons, which have a lubricating lining called synovium or synovial membrane, slide back and forth within the carpal tunnel when you use your hand and fingers.

Carpal tunnel syndrome is probably related to a combination of factors. As a general rule, any condition that causes swelling, thickening or irritation of the synovial membranes that surround the tendons in the carpal tunnel may result in pressure on the median nerve. This is especially true for people who are born with a smaller carpal tunnel. Conditions that can reduce the space within the carpal tunnel or put pressure on the median nerve include:


inflammatory conditions such as rheumatoid arthritis, gout or tenosynovitis (swelling of the tendons)
wrist joint injury, such as a sprain, fracture or dislocation
benign (noncancerous) tumors of the wrist
thyroid disease
obesity
swelling from conditions such as congestive heart failure or pregnancy
Symptoms of carpal tunnel syndrome most often occur among people who do repetitive work or activities with their hands, such as keyboard users, typists, assembly-line workers, meat packers, carpenters, farmers, gardeners and those who sew or knit frequently. Certain sports activities, such as golf and canoeing, can also lead to similar symptoms. Women are affected about three times more often than men, possibly due to the fact that women tend to have smaller carpal tunnels than men.


Signs/symptoms
Common symptoms of carpal tunnel syndrome include:
numbness and tingling in some of your fingers (usually the thumb, index and middle finger), possibly strong enough to wake you at night
a heavy feeling in your hand or fingers
burning pain in your hand, wrist and fingers
tingling, pain and numbness radiating up your arm, and possibly into your shoulder
difficulty or inability to make a fist or pick things up
In severe cases, feeling in the fingers may be lost completely, the entire hand may be weak and the muscles at the base of the thumb can waste away.

Carpal tunnel symptoms tend to occur more often at night and when lying down, due to the natural fluid redistribution that occurs in the soft tissues. Wrist positions used for certain activities, such as holding onto the steering wheel or a reading a newspaper, can also aggravate symptoms. How long the symptoms last depends on the severity of your condition, as well as how you respond to treatment.


Diagnosis
If yoult your doctor. Early diagnosis and treatment can help prevent nerve damage.
Your doctor will ask about your health history, current symptoms, activities at work and hobbies. Simple tests may be done to determine the degree of median nerve irritation, such as tapping the inside of your wrist, asking you to hold your wrist in a downward bent position for about a minute, or gently pricking your hand or fingers.

If necessary, the doctor may use various nerve conduction tests to see if the sensory nerves in your wrist are conducting impulses at a normal rate and whether the muscles are receiving normal nerve impulses.

X-rays, computed tomography (CT scan, a computer-generated, cross-sectional picture of internal body parts) or magnetic resonance imaging (MRI, an imaging technique based on computer analysis of the body's response to a magnetic field) of the wrist may be done to help identify carpal bone problems or wrist tumors. Because carpal tunnel symptoms can be caused by irritated or compressed nerves near your neck and spine, the doctor may do X-rays, a CT scan or MRI of your neck as well.

Sometimes, blood tests are done to determine if a specific medical condition is responsible for the symptoms.


Treatment
Most people respond to conservative treatment. If these approaches aren't effective, your doctor may suggest surgical treatment.
Conservative treatment
To treat carpal tunnel syndrome, rest your wrist and hand as much as possible. Elevation can help relieve swelling. You may find temporary relief by shaking your hand or, at night, hanging your arm over the side of the bed. Ice packs may help relieve swelling.

Avoid tasks that require repetitive twisting and turning of your wrist, and modify how you do repetitive tasks so they don't strain your wrist. Use your unaffected hand when possible.

Use good posture and wrist positioning. You may need to adjust your workstation, especially the height of your desk and chair. An ergonomics consultant can help you create a healthy work space.

Your doctor may recommend wearing a splint to relieve pressure and support your hand and wrist. Depending on your symptoms, you may wear the splint full time or only at night for several weeks.

Your doctor or a physical therapist may teach you exercises that can lessen carpal tunnel symptoms and clumsiness in your wrist or hand. Yoga, which has been shown to reduce pain and improve grip strength, may also be beneficial.

Cortisone injections into the carpal tunnel may provide dramatic, but temporary, results. Oral cortisone is sometimes recommended, but may be less effective than the injections.

If the compression is caused by fluid retention, a diuretic (a medication that helps the body get rid of fluid through increased urination) may be recommended.

If an underlying illness such as diabetes or arthritis is causing your symptoms, treatment should first focus on the underlying illness.

Other treatments may include chiropractic care, acupuncture, vitamin B6 supplements, magnetic therapy and ultrasound therapy. Further research is needed to verify the effectiveness of these treatments, however.

Surgical treatment
If your symptoms don't improve with conservative treatment, surgery may be recommended. It's often done in an outpatient facility with a local anesthetic that numbs the wrist and hand. Symptoms usually improve after surgery, but full recovery may take several months. Although most people recover without problems, complications may include infection, nerve damage and hand stiffness.

Surgical procedures to treat carpal tunnel syndrome include:

Open carpal tunnel release: Open release of the transverse carpal ligament is typically done by an orthopedic surgeon. First, the surgeon makes an incision in the palm of your hand. Then, the transverse carpal ligament is separated to open up the carpal tunnel space. The incision is then closed over the separated ligament.

Endoscopic carpal tunnel release: With endoscopic carpal tunnel release, the surgeon makes a tiny incision in your wrist, just below the beginning of the crease in your palm. Then, the surgeon threads a small tube equipped with a fiberoptic camera called an arthroscope into the incision and cuts the transverse carpal ligament. Endoscopic surgery may be followed by less pain and a more rapid return to normal hand function than open surgery. Endoscopic procedures may have a higher risk nerve injury complications, however.
Treatment considerations
Make sure you understand your treatment options, the risks and benefits, and possible costs to you. It's especially important to review these with your doctor before any surgical procedure.


Complications
Often, carpal tunnel syndrome is not serious. However, long-term pressure on the median nerve can cause nerve damage. If left untreated, carpal tunnel syndrome can cause atrophy and permanent changes in some of the thumb muscles.

Pregnancy-specific information
Retaining fluid -- a common symptom of pregnancy -- can cause swelling around the tunnel, especially during the third trimester. Carpal tunnel syndrome may be present until the fluid retention resolves at the end of the pregnancy.

Senior-specific information
You're more likely to develop carpal tunnel syndrome as you get older. Normal aging makes the synovium around the tendons thick and sticky, which may cause the median nerve to be compressed within the carpal tunnel. During menopause, hormonal changes may cause swelling around the carpal tunnel.

Prevention
There are many steps you can take to help prevent carpal tunnel syndrome and other hand problems. For example:
Lose excess weight.

Seek treatment for any underlying disease.

Try not to bend, extend or twist your hands repetitively for long periods of time. When doing repetitive tasks with your hands, switch hands when possible. Take regular breaks, at least once an hour, to do a few minutes of hand exercises. Try making a fist, then opening it and fanning out your fingers. You may also want to talk to your doctor about special fingerless gloves that support your hands during repetitive tasks.

Use equipment properly. Sit up straight and use correct hand, wrist and arm positions at the keyboard. Hold your wrists in a neutral (straight) position. Keep your elbows near the side of your body, and be sure your desk and computer are the right height.

Use tools that are the right size and don't vibrate too much. Consider using anti-vibration gloves if necessary.

For any activity, make sure youally designed ergonomic products, such as padded hand tools intended to minimize wrist overuse and incorrect positioning. For the computer, you may consider:
alternative keyboards (for example, larger or smaller keys or right- or left-handed keyboards)
joysticks or trackballs that can be used instead of a mouse
keyboard "macros" that allow a few keystrokes to replace multiple keystrokes
keyguards that stabilize your hand movements, preventing multiple keystrokes
devices designed to support your wrist at the keyboard