The carpal tunnel syndrome is manifested by numbness and tingling in the fingers, and a loss of muscle strength in the wrist and hand affected.
The symptoms result from compression of the median nerve at the wrist (see diagram). In the wrist, the median nerve and the flexor tendons of the fingers pass through a “tunnel” called the carpal tunnel. This channel is relatively small. Any condition that reduces this space, such as inflammation , causes compression of the median nerve. Some movements of the fingers, especially the thumb, are then controlled less well or at all. The sensations in the hand can also be modified.
The carpal tunnel syndrome affects about 11% of women and 3.5% of men. It tends to appear either in the early fifties, or past the age of 75 years. The symptoms are initially light and transient, and then intensify with time.
Causes of carpal tunnel syndrome
The origin of the carpal tunnel syndrome is often multifactorial. The risk is higher for workers exposed to the following situations.
- The repetition of movements of the wrist and the forearm for prolonged periods.
- Movements that require significant force in the hand.
- The restrictive postures for the hand.
- The manipulation of tools that vibrate.
For the moment, it is not known if computer work can contribute to the problem. Indeed, studies to date have not established a clear link between regular keyboard use and carpal tunnel syndrome. However, frequent use of the mouse (more than 20 hours per week) increases the risk, according to a study.
Other possible causes include wrist injuries, wrist arthritis, and neurological damage as a result of diabetes.
Hormonal fluctuations experienced during menopause, pregnancy or hypothyroidism create an environment conducive to carpal tunnel syndrome. During pregnancy, for example, fluid retention adds pressure to the median nerve.
The duration of symptoms varies depending on the cause. Carpal tunnel syndrome can usually be effectively treated without a permanent decrease in the volume of the muscles of the hand (atrophy).
Researchers have observed, in a study, that in a third of cases, carpal tunnel syndrome disappears spontaneously without treatment.
If the symptoms are not relieved by the usual treatments, surgery may be considered.
Symptoms of carpal tunnel syndrome
- Of numbness or tingling in the hand and fingers (especially the thumb, index and middle finger).
- A pain in the wrist and the palm, which irradiates to the fingers or to the forearm (sometimes to the shoulder).
- Difficulty grasping objects, even light ones.
Often, the symptoms get worse:
- During the night;
- the activity, for example while driving a vehicle or holding the phone;
- in women, before menstruation, during the last months of pregnancy and shortly after childbirth.
People at risk
- People who work vibration- producing machinery , housekeeping workers, food industry workers, production line workers, service attendants ( food and beverages), truck and bus drivers and possibly people who work on the computer using a lot of the mouse (more than 20 hours a week).
- People whose family member has already suffered from this condition. Certain physiognomic features, such as the shape of the wrist, may increase the risk.
- People who indulge in certain hobbies , such as gardening, needlework, video games, golf, boating and wheelchair sports.
- Pregnant women and those who are in menopause.
- Certain diseases such as diabetes, rheumatoid arthritis or hypothyroidism, if they are not treated or controlled.
- Taking oral contraceptives.
- Wrist injuries.
|Basic preventive measures|
The electromyogram (EMG) is sometimes used to confirm the diagnosis when symptoms are not typical or prior to surgery. This is an examination done by a neurologist that measures the speed of nerve conduction in the wrist. This examination makes it possible to know if it is the median nerve that is affected, and to what degree.
We must first treat any illness or injury that could be the cause of the syndrome. Wrist and hand pain usually disappear as soon as you treat, for example, the hypothyroidism that caused them.
In the absence of an injury or other associated disease, the treatment consists first of resting the affected wrist by interrupting the repetitive activity that causes it or by changing the pace and intensity.
The doctor sometimes suggests wearing a splint during the night. The splint prevents bending of the wrist and thus compresses the median nerve while sleeping.
Apply ice where the pain is felt, for 10 to 12 minutes, a few times during the day. The application of heat can also help to calm the pain in the immediate future. It is also advisable to perform a contrast hydrotherapy once a day: immerse the hand and wrist for 3 minutes in a bowl of hot water, then for 30 seconds in cold water. Repeat the exercise 3 times in a row.
If necessary, analgesic drugs (acetaminophen) or anti-inflammatories (aspirin, Advil, Motrin, etc.) can sometimes relieve pain, but are generally not very effective for this type of condition. Note that anti-inflammatories do not accelerate healing.
In more serious cases, the doctor may suggest a cortisone injection at the entrance of the carpal tunnel. This treatment provides relief for 3 months, on average.
A few tips
– Use more non-painful hand.
If the above means are not enough to remove the symptoms, a physiotherapy program could be beneficial, although its effectiveness has not been clearly demonstrated. The purpose of the treatment is to decrease the inflammatory reaction in the tissues surrounding the median nerve and to strengthen the muscles of the wrist and hand joints.
If the pain persists after several months of treatment and the work is at risk of recurrence, surgery may be considered followed by physiotherapy. Surgery involves cutting the ligament that is squeezing the median nerve (see diagram).
Surgery can be performed by incision of about 5 cm (2 in) on the wrist or endoscopy, with 2 small incisions (one is used to introduce a tube with a tiny camera and the other, the surgical instrument) .
A lasting relief of pain, numbness and tingling occurs in the vast majority of people so treated. There are some risks, however, such as damage to the nerve either temporarily (1 in 100) or permanently (1 in 1,000).