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Carpal Tunnel Syndrome Overview
Carpal tunnel syndrome is a hand and arm condition that causes numbness, tingling and other symptoms. Carpal tunnel syndrome is caused by a pinched nerve in your wrist.
A number of factors can contribute to carpal tunnel syndrome, including the anatomy of your wrist, certain underlying health problems and possibly patterns of hand use.
Bound by bones and ligaments, the carpal tunnel is a narrow passageway located on the palm side of your wrist. This tunnel protects a main nerve to your hand and the nine tendons that bend your fingers.
Compression of the nerve produces the numbness, tingling and, eventually, hand weakness that characterize carpal tunnel syndrome.
Fortunately, for most people who develop carpal tunnel syndrome, proper treatment usually can relieve the tingling and numbness and restore wrist and hand function.
Carpal Tunnel Syndrome Causes
The following are risk factors associated with the development of carpal tunnel syndrome:
- arthritis and other causes of inflammation of the wrist
- Endocrine disorders such as diabetes and hypothyroidism
- Wrist fracture
Carpal tunnel syndrome is rare in children.
The relationship between work and carpal tunnel syndrome is unclear. Positions of extreme wrist flexion and extension are known to increase pressures within the carpal canal and apply pressure on the nerve. This is particularly true with repetitive strain injury to the wrist. Intensity, frequency, and duration of work activity and their relationship to carpal tunnel syndrome are unclear.
What are carpal tunnel syndrome symptoms?
People with carpal tunnel syndrome initially feel numbness and tingling of the hand in the distribution of the median nerve (the thumb, index, middle, and thumb side of the ring fingers). These sensations are often more pronounced at night and can awaken people from sleep. The reason symptoms are worse at night may be related to the flexed-wrist sleeping position and/or fluid accumulating around the wrist and hand while lying flat. Carpal tunnel syndrome may be a temporary condition that completely resolves or it can persist and progress.
As the disease progresses, patients can develop a burning sensation, and/or cramping and weakness of the hand. Decreased grip strength can lead to frequent dropping of objects from the hand. Occasionally, sharp shooting pains can be felt in the forearm. Chronic carpal tunnel syndrome can also lead to wasting (atrophy) of the hand muscles, particularly those near the base of the thumb in the palm of the hand.
Treating carpal tunnel syndrome
In some cases CTS will disappear without treatment, or simple self-care measures will reduce the symptoms.
CTS in pregnant women often gets better within three months of the baby being born, although it may need treatment. In some women, symptoms can continue for more than a year.
Non-surgical treatments, such as wrist splints and corticosteroid injections, are used to treat mild or moderate symptoms.
Surgery may be required if non-surgical treatments fails to relieve the symptoms. It may also be used if there is a risk of permanent nerve damage.
Surgery relieves the symptoms of mild CTS immediately. But in those with severe nerve damage, it can take a while to recover or there may not be any improvement.
Depending on which hand was operated on and what your job involves, you will usually be able to return to work within a few weeks of surgery.
How is carpal tunnel syndrome diagnosed?
The diagnosis of carpal tunnel syndrome is suspected based on the symptoms and the distribution of the hand numbness. Examination of the neck, shoulder, elbow, pulses, and reflexes can be performed to exclude other conditions that can mimic carpal tunnel syndrome. The wrist can be examined for swelling, warmth, tenderness, deformity, and discoloration. Sometimes tapping the front of the wrist can reproduce tingling of the hand and is referred to as Tinel’s sign of carpal tunnel syndrome. Symptoms can also at times be reproduced by the examiner by bending the wrist downward (referred to as Phalen’s maneuver).
The diagnosis is strongly suggested when a nerve conduction velocity test is abnormal. This test involves measuring the rate of speed of electrical impulses as they travel down a nerve. In carpal tunnel syndrome, the impulse slows as it crosses through the carpal tunnel. A test of muscles of the extremity, electromyogram (EMG), is sometimes performed with the nerve conduction velocity test to exclude or detect other conditions that might mimic carpal tunnel syndrome.
Blood tests may be performed to identify medical conditions associated with carpal tunnel syndrome. These tests include thyroid hormone levels, complete blood counts, and blood sugar and protein analysis. X-ray tests of the wrist and hand might also be helpful to identify abnormalities of the bones and joints of the wrist.