Carpal tunnel syndrome

Carpal tunnel syndrome is a painful hand condition caused by a pinched nerve in the wrist.

Symptoms include tingling and numbness that can make even simple tasks hard to perform. Certain factors, such as your wrist anatomy, pregnancy, arthritis and other health conditions, can increase your likelihood of developing carpal tunnel syndrome. 

Initial treatment for carpal tunnel syndrome aims to reduce tingling and numbness and restore wrist and hand function without surgery. If this is unsuccessful, an operation may be recommended.

Causes

The main symptoms of carpal tunnel syndrome are caused by irritation to the median nerve.

The median nerve passes through the carpal tunnel in the wrist. It controls some of the movements of the thumb, as well as sensation in the thumb, the index and middle fingers, and half of the ring finger.

The carpal tunnel is a narrow space inside the wrist that is surrounded by bone and ligament. This space lets certain tendons as well as the median nerve pass from the forearm into the hand.

With carpal tunnel syndrome, the tendon sheaths may thicken and enlarge. This reduces the amount of space inside the carpal tunnel. As a result, the median nerve may be compressed. This compression can cause permanent nerve damage if left untreated. 

Risk factors

In most cases, it is likely that a number of risk factors contribute to the median nerve becoming compressed. These may include:

  • a family history of carpal tunnel syndrome – your genetics influence things like the anatomical shape of your carpal tunnel
  • pregnancy – up to about 50% of pregnant women develop CTS, possibly due to fluid retention increasing the pressure in the carpal tunnel
  • injuries to the wrist
  • other health conditions, such as diabetes , which increases your risk of nerve damage, and rheumatoid arthritis, which can cause inflammation of the tendons in the wrist
  • repetitive work with the hand
  • obesity
  • various types of hormonal conditions.

Carpal tunnel syndrome is 5 times more common in women than in men and most often occurs in people between the ages of 30 and 60.

Symptoms 

Carpal tunnel syndrome usually starts with a tingling or numbness that tends to affect the thumb, index finger and middle finger. General discomfort in the wrist or arm may also be present and some people experience a weakened grip. 

At first, symptoms may wake you up at night. Later, they may also occur during your daily routines. For instance, you may notice symptoms while you are driving or holding a newspaper. Your symptoms may become more severe over time.

When to see a doctor

If you have ongoing symptoms that sound like carpal tunnel syndrome, especially if they interfere with your sleep or stop you from carrying out your normal activities, see your doctor. If you leave the condition untreated, permanent nerve and muscle damage can occur.

Diagnosis

Carpal tunnel syndrome is usually diagnosed by your doctor. They will perform a physical examination and ask questions to learn more about your symptoms. Further testing is usually only required if your doctor is uncertain and wants to rule out other conditions that have similar symptoms.

Other tests may include:

  • Blood tests – if your doctor suspects an underlying condition, such as diabetes, rheumatoid arthritis or underactive thyroid.
  • Nerve conduction study – to find out how much damage has been done to your nerves.
  • Electromyography – to find out how well your muscles are responding when a nerve is stimulated, to indicate nerve damage.
  • X-ray – to exclude other causes of wrist pain, such as arthritis or a fracture.
  • Ultrasound scan – to examine the structure of your wrist.

Once your problem is diagnosed, you and your doctor can make a treatment plan. 

Treatment & self care

Treatment for carpal tunnel syndrome depends on the severity of your symptoms and how long you have had them. In some cases, symptoms improve within a few weeks. You may be able to help ease discomfort by:

  • taking frequent breaks to rest your hands
  • avoiding activities that make symptoms worse
  • applying cold packs to reduce any swelling.

If these measures do not relieve symptoms within a few weeks talk to your doctor. There are a range of non-surgical and surgical treatments available.

  • Non-surgical treatments such wrist splints and corticosteroid injections are normally offered first. 
  • Surgery is usually recommended only when other treatments have failed to relieve symptoms. Your surgeon will be able to discuss the most suitable method of surgery with you.

Learn more

Carpal tunnel syndrome online learning The Orthopaedic Academy of Orthopaedic Surgeons
Carpal tunnel syndrome
Mayo Clinic (US)
Carpal tunnel syndrome NHS Choices (UK)
Carpal tunnel section National Institute of Health (USA)

References

Carpal tunnel syndrome: Continuing medical education Mellow, C. NZ Family Physician  Vol 34 No 1, Feb 2007 
Carpal tunnel syndrome: An overview of best practice NZ Accident Compensation Corporation (ACC) Review 44, 2009

Credits: Health Navigator.