Carpal tunnel syndrome

The carpal tunnel is located in the area of the wrist. Tendons and the median nerve run through it. With a carpal tunnel syndrome, the hand briefly goes to sleep, tingles and can be painful. How does it develop and what can relieve the symptoms?

At a glance

  • In people with carpal tunnel syndrome, the hand briefly goes to sleep, tingles and can be painful.
  • Excessive and improper loads on the wrist can play a part in that.
  • The carpal tunnel is located in the area of the wrist. Tendons and the median nerve run through it.
  • If the tissue in the carpal tunnel swells up and presses on the median nerve, this causes carpal tunnel syndrome.
  • With mild to moderate symptoms, a splint is usually sufficient. Cortisone injections can also temporarily relieve the symptoms.
  • Sometimes an operation is considered.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Carpal tunnel syndrome: woman holding her arms in the air and clutching her left wrist.

What is carpal tunnel syndrome?

Many people experience their hand going to sleep for a short while every now and then. It feels numb and tingly. But this unpleasant feeling usually disappears quickly again. Anyone who has carpal tunnel syndrome has similar symptoms – but these return repeatedly and pain often appears.

The carpal tunnel is a canal located on the inside of the wrist. It is surrounded by bone and connective tissue. A solid band of connective tissue, the carpal ligament (flexor retinaculum), spans it. Tendons and the median nerve (Nervus medianus) run through the canal. This nerve controls the sensitivity and flexibility of the ball of the thumb, but also other parts of the hand.

If the tissue in the carpal tunnel swells up, it can press on the median nerve and cause carpal tunnel syndrome. The symptoms often disappear again by themselves. But sometimes they last longer. The symptoms can be alleviated with various treatments.

What are the symptoms of carpal tunnel syndrome?

With carpal tunnel syndrome, symptoms occur when the tissue in the carpal tunnel swells up and presses more intensely on the median nerve.

The following symptoms are possible:

  • Loss of sensation: parts of the hand feel numb or tingly (commonly called pins and needles). Normally the thumb, index, middle and ring fingers are affected. An initial typical indication is a hand going to sleep at night.
  • Pain: sometimes it is not just the fingers, but the whole hand that hurts. The pain can also spread into the arm.

The symptoms usually occur at night and toward morning. As a general rule, both hands are affected, but not necessarily at the same time. The symptoms often abate when the hand is shaken out.

What are the causes of carpal tunnel syndrome?

It is often difficult to explain exactly why the tissue in the carpal tunnel swells up. Excessive and improper loads on the wrist, for instance due to high pressure and intense stretching or flexing, can be partly responsible. But tasks associated with strong vibrations can also promote the disorder – for example working with a jackhammer.

For many people with carpal tunnel syndrome, the discomfort increases with such loads. It is unclear whether they can also cause carpal tunnel syndrome. There is speculation that working at a computer might also foster carpal tunnel syndrome. According to previous studies however, working at a computer has little impact on the syndrome’s development.

Important: The risk of carpal tunnel syndrome also increases with certain diseases. These include for instance diabetes mellitus, rheumatism, wrist injuries and recurrent tendinitis. The risk is also somewhat greater during pregnancy, during which more fluid accumulates in the tissue.

Sudden and very severe symptoms only occur rarely. This is referred to as acute carpal tunnel syndrome. It is usually caused by inflammation, injuries or bleeding in the wrist.

How common is carpal tunnel syndrome?

Carpal tunnel syndrome is most common in people aged 40-70 years. It is extremely rare in children.

Approximately 3 out of every 1000 people develop carpal tunnel syndrome every year.

Men get carpal tunnel syndrome less often than women. It is more common in people who do physical labor. 3 out of 1,000 people are estimated to get carpal tunnel syndrome every year.

How does carpal tunnel syndrome develop?

Some people with carpal tunnel syndrome have only mild symptoms that come and go for years. The symptoms are estimated to ease within 6 months without treatment in about a third of cases. For others, the symptoms are long-lasting. In advanced stages of the condition, the hand can feel constantly numb. At a late stage, muscular atrophy in the ball of the thumb is a possible outcome. If the strength and feeling in the hand diminishes, it can be difficult for people with carpal tunnel syndrome to grip things properly – for instance a cup or glass.

How is carpal tunnel syndrome diagnosed?

To diagnose carpal tunnel syndrome, the doctor initially asks about the symptoms. An examination of the hand and wrist is then conducted. In the course of this, certain tests are used to examine flexibility and sensitivity. The doctor also examines whether there are sensory disturbances or numbness in the hand or fingers.

To clarify whether carpal tunnel syndrome is causing the symptoms, electrophysiological examinations may moreover be required – for instance electroneurography. These can be used to detect how well the nerves are conveying electric pulses or whether the nerve function is limited. The results of the examination are considered along with the symptoms, physical examination, circumstances and case history.

For diagnosis of carpal tunnel syndrome, it is also important for other possible causes to be ruled out. For example, changes to the cervical spine can irritate the nerve roots. Other diseases of the nervous system can also cause similar symptoms – like polyneuropathies.

How is carpal tunnel syndrome treated?

Mild to moderate symptoms can usually be treated with a splint at first, which is worn at night. It prevents the wrist from bending. Doctors also advise avoiding loads which are suspected to be linked with the symptoms.

Cortisone injections into the carpal tunnel may temporarily relieve the symptoms. But cortisone injections do not help in the long run.

Surgery can also be a good idea for people with carpal tunnel syndrome. During an operation, the carpal ligament that stretches across the carpal bones is cut through. Stress on the median nerve is thus relieved. But while an operation can permanently eliminate the symptoms, it is not always necessary. At the start of the condition in particular, another treatment is usually chosen. Only the rare case of acute carpal tunnel syndrome usually requires urgent surgery. 

For more detailed information, for example on surgery for carpal tunnel syndrome, visit gesundheitsinformation.de.

Studies indicate that an extracorporeal shockwave therapy (abbreviated to ESWT) can also relieve the symptoms. With this treatment, sound waves are applied to the skin with high external pressure. A shockwave therapy is not usually paid for by statutory health insurance.

Important: There are still other treatment methods that are sometimes recommended for carpal tunnel syndrome. These include for instance ultrasound, magnetic field and laser therapies, or even acupuncture. But their effectiveness is unproven.

Many people with carpal tunnel syndrome resort to painkillers to relieve the symptoms – especially non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, which are available over the counter in drugstores. There are also recommendations to take vitamin B6 preparations. Remedies like these should strengthen the nerves. But the studies previously carried out suggest that neither NSAIDs nor vitamin B6 can relieve symptoms adequately.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen) (IQWiG). As at:

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