Carpal Tunnel Syndrome

What is it?

Carpal tunnel syndrome (CTS) is a condition that can cause pain, tingling, numbness and weakness in your fingers and thumb.

In the wrist, the median nerve and several tendons pass through a bony arch called the carpal tunnel. The median nerve carries signals between the hand and spinal cord and provides sensation to the thumb, index finger, third finger and parts of the fourth finger. The median nerve also supplies the small thenar muscles located at the base of the thumb. Tendons allow the fingers to bend. Swelling around the tendons causes increased pressure on the median nerve. This pressure, in turn, causes the numbness, tingling and weakness associated with CTS.

What causes it?

Anything that causes swelling of the synovium that surrounds the tendons, or produces repeated pressure on the median nerve can lead to CTS or make it worse if the condition already exists. Causes may include the following:

  • Injuries that damage the wrist.
  • Arthritis conditions, such as rheumatoid arthritis, which can cause swelling of tissues in the carpal tunnel, resulting in pressure on the median nerve.
  • Work activities and hobbies that require repetitive wrist or finger motion, especially in combination with forceful pinching or gripping, or activities involving vibrating hand tools or instruments that put pressure at the base of the palm.

Who gets it?

Carpal tunnel syndrome may affect one or both hands and can occur at any age. Use-associated CTS is most commonly observed in people between the ages of 20 and 50, while non-use-associated CTS is generally seen in people over 50. Regardless of age, CTS occurs more often in women than in men. In cases of non-use-associated CTS, arthritis of the wrist occurs frequently. Tendinitis or another condition also can cause the swelling which compresses the median nerve.

What are the symptoms?

If you have CTS, you may experience any of the following symptoms:

  • Pain, tingling and numbness in your thumb, index, middle and/or ring fingers.
  • Pain that shoots from your hand up your arm as far as your shoulder.
  • A swollen feeling in your fingers, even though they may not be visibly swollen.
  • You have trouble grasping objects.

Although CTS can begin suddenly, its onset usually is gradual.

How is it diagnosed?

Detailed medical history, and one or all of the following tests:

  • Tinel's sign: tap the front of your wrist to check for tingling/pain.
  • Phalen's sign: bend wrist down and hold then release to check for tingling/pain.
  • Nerve conduction velocity study: measures nerve's ability to send electrical impulses.
  • Blood test and X-rays: to check for other medical conditions.

How is it treated?

The goal of treatment is to relieve pain and prevent CTS from getting worse. The type of treatment you use depends on the severity of your CTS. Treatment may include one or all of the following:

  • Splints.
  • Medications: NSAIDs, injections of corticosteroids into the carpal tunnel.
  • Work changes: an occupational therapist may help find ways of modifying work activities.
  • Surgery: Carpal tunnel release to relieve the pressure on the median nerve.

What is the outlook?

If not treated, it can lead to permanent nerve and muscle damage, possibly resulting in reduced hand function. With early diagnosis and treatment, however, complete recovery generally is possible.