Causes of carpal tunnel syndrome

Carpal tunnel syndrome can have various causes. A naturally narrow carpal tunnel, a heavy strain on the wrist, injuries and inflammatory changes favour the development of carpal tunnel syndrome. The carpal tunnel is actually an anatomical, tunnel-like passage for tendons and nerves into the hand.

In this tunnel lies an important nerve, the median nerve.Due to the disease-related bottleneck in the carpal tunnel, the median nerve is mechanically stressed and irritated. The injury to the sensitive nerve causes it to be disturbed in its functions. The nerve supplies the thumb ball musculature and is responsible for the sensitive sensation of thumb, index finger, middle finger and parts of the ring finger.

The pressure on the nerve in the narrow carpal tunnel causes sensations in the area supplied by the nerve. Those affected therefore suffer from tingling, “formication”, numbness and pain in fingers and palm. The symptoms can radiate into the arm.

If carpal tunnel syndrome remains untreated for a long time, the nerve damage progresses and over time the muscles of the ball of the thumb atrophy. This is because the pressure on the nerves damages all supply areas of the median nerve over time. This includes the ball of the thumb, which can be used less and thus loses function and muscle mass.

Can carpal tunnel syndrome also cause symptoms in other areas such as the shoulder or arm?

A carpal tunnel syndrome triggers typical symptoms such as pain and paresthesia in the area supplied by the affected median nerve. The palm, thumb, index finger and ring finger are particularly affected. However, the symptoms, both pain and paresthesia, such as tingling or formication, can radiate. It is possible that the symptoms reach into the arm or even the shoulder-neck area.

History

The course of carpal tunnel syndrome is highly variable. The symptoms can be chronically progressive, recurring with pauses or disappearing spontaneously. The latter occurs particularly in younger patients, for example after the end of a pregnancy or after reduction of an activity that causes symptoms.

The longer a carpal tunnel syndrome exists and the older the patients are, the less likely they are to experience a spontaneous improvement in symptoms. In the early stages of the disease, which can last for years, this may also be successful. The cause of these nocturnal complaints lies in the unnoticed bending of the hand during sleep, which causes an increase in pressure in the carpal tunnel, which in already tight conditions leads to exhaustion of the nerve adaptation to the changed conditions and the median nerve is thus damaged by pressure.

By changing the position of the wrist, the reserve space can be sufficient again and the nerve can recover, so that the complaints initially disappear again. A wrist splint, for example, is suitable for this purpose. However, the greater the narrowness in the carpal tunnel, the slower the recovery will take place, until finally a permanent sensory disturbance occurs.

This sensory disorder affects the thumb, index finger, middle finger and ring finger on the palm side. Tingling sensation disorders of the middle three fingers are particularly common. The pain radiates from the hand and usually affects the forearm and can even reach the shoulder.

In the course of the disease, it does not only remain with the nightly pain and sensations. Increasingly, the symptoms also occur during the day. In addition, the damage during the course of the disease increasingly affects the function of the wrist muscles.

Patients often report “clumsiness” and sudden “weakness” of the hand. They report about suddenly dropped glasses or bottles, but also that there are difficulties with the pointed grip between thumb and index finger. The sensitivity of the skin on the thumb, index, middle and ring fingers is reduced more and more.

In the end, tactile recognition is disturbed. In the advanced stages of the disease, there may be visible loss of the thumb ball muscles (atrophy). A firm grip of the hand is then no longer possible. Fortunately, the complete loss of skin feeling in the hand occurs very rarely nowadays.