Carpal Tunnel Syndrome - Causes

High Force and Vibration. Still, even though medical and physical conditions may be the initial culprits leading to CTS, certain working conditions are significantly related to nerve damage--if not to pure cases of CTS. Work that involves repetitive hand and wrist work in cold temperatures, high force, and vibration is particularly hazardous.

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In addition to CTS, other disorders of hand and wrist are attributed to these work-related movements. They include the following:

Hand-arm vibration syndrome.
Cumulative trauma disorder.
Overuse syndromes.
Chronic upper limb pain syndrome.

All of these problems are generally associated with repetitive and forceful use of the hands that damage muscles and bones of the upper extremities.

Incorrect Posture. Incorrect posture may also play a role in the development of CTS in people who work at a computer and other types of keyboards. The tendency to roll the shoulders forward, round the lower back, and thrust the chin forward can shorten the neck and shoulder muscles, compressing nerves in the neck. This, in turn, can affect the wrist, fingers, and hand. Evidence is not as strong for a causal relationship, because people with poor posture may also have physical abnormalities that increase the risk for CTS.

Psychosocial Factors in the Workplace. Studies indicate that psychosocial factors in the workplace, such as intense deadlines, a poor social work environment, and low levels of job satisfaction, are major contributors to carpal tunnel pain. Such psychosocial conditions are more likely to be important factors in contributing to CTS in office workers, although they also complicate the condition in workers whose work is primarily physical.

Medical Conditions

A number of medical conditions increase the risk for or even cause CTS. The main conditions associated with CTS are diabetes, hypothyroidism, rheumatoid arthritis, osteoarthritis, obesity, and pregnancy. Many of the underlying diseases that contribute to the development of CTS are also associated with more severe forms of CTS.

Diabetes. CTS is a very common feature of diabetic neuropathy, one of the major complications of diabetes. Neuropathy is decreased or distorted nerve function; it particularly affects sensation. Symptoms include numbness, tingling, weakness, and burning sensations, usually starting in the fingers and toes and moving up to the arms and legs. About 6% of patients with CTS have diabetes. A 2005 study reported that an estimated 85% of patients with type 1diabetes develop CTS. Development of CTS was related to the patient?s age and the length of time they had had diabetes, but not to the development of diabetes-related complications such as neuropathy or kidney disease