We don't always know what causes carpal tunnel syndrome. In fact, in most cases no obvious cause can be found.
However, any condition that lessens the amount of space in the carpal tunnel can compress the median nerve in the tunnel. These include:
- Various injuries, including previous fractures of the wrist
- Medications that may lead to fluid retention, including oral contraceptives (birth control pills)
- Hormonal changes and conditions that lead to fluid retention, such as pregnancy (CTS that occurs during pregnancy usually disappears within four to six weeks following delivery)
- Medical disorders that involve constricted blood vessels, such as
- Medical disorders that lead to fluid retention or are associated with inflammation, such as
rheumatoid arthritis, diabetes, hypothyroidism, Lyme disease, and others.
The following can increase the chance of developing carpal tunnel syndrome:
- Cigarette smoking, which constricts blood vessels
- Obesity, which can increase pressure on the nerves in the wrist
Nice To Know:
CTS and Repetitive Strain Injury
During the 1970s it became popular to attribute many painful conditions of the upper limb joints and tendons to so called repetitive strain injuries (RSI), also known as cumulative trauma disorders (CTD). These types of injuries were said to result from prolonged overuse of the upper extremities by performing too many fast, repetitive motions of the shoulders, elbows, hand, and fingers.
Some researchers believe that overuse of the wrist may be a cause of carpal tunnel syndrome. But this is not accepted by all physicians. Today, repetitive strain injury is becoming less recognized as the entity causing carpal tunnel symptoms. Indeed, many physicians now question the validity of this diagnosis.
Those who believe in RSI as a cause of carpal tunnel syndrome assume that:
Repetitive strain injuries: