Carpal tunnel syndrome

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

Key points

  1. Carpal tunnel syndrome usually starts with a tingling or numbness in the hands and fingers, which becomes increasingly painful.
  2. The symptoms can be felt at night or during daily tasks, such as driving, holding a book, working on a keyboard, or playing a musical instrument.
  3. Carpal tunnel syndrome is more common during pregnancy, menopause, arthritis, after having had a wrist injury or with health conditions such as diabetes or rheumatoid arthritis. It may also be due to repetitive activities, such as work-, recreational- or sports-related tasks.
  4. Initial treatment for carpal tunnel syndrome aims to reduce pain, tingling and numbness, and restore wrist and hand function.

What causes carpal tunnel syndrome?

The main symptoms of carpal tunnel syndrome are thought to be caused by irritation to one of the nerves in the hand, the median nerve. Often this happens without any clear reason.

  • 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 tunnel protects the finger tendons, nerves and blood vessels where they pass from the forearm into the hand.
  • With carpal tunnel syndrome, the tendon sheaths may have thickened. Alternatively, there may be fluid retention in the tunnel, as could happen when sleeping with the wrists bent.
  • Thickening of the tendon sheaths or fluid retention can reduce the amount of space inside the carpal tunnel.
  • As a result, the median nerve may be compressed, and the person then feels pain and tingling, particularly on the thumb side of the palm, thumb, and fingers.

In most cases, there are a number of possible causes of pain and tingling in the hands and fingers.

Possible causes of pain and tingling in the hands and fingers

  • pregnancy: up to about 50% of pregnant women develop hand and finger pain, possibly due to fluid retention in the carpal tunnel
  • injury to the wrist
  • other health conditions, such as diabetes, which can make nerves more sensitive, and rheumatoid arthritis, which can cause inflammation of the tendons in the wrist
  • repetitive work with the hand
  • obesity
  • various types of hormonal conditions
  • a family history of carpal tunnel syndrome. Your genetics influence things like the anatomical shape of your carpal tunnel.

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.

What are the symptoms of carpal tunnel syndrome?

Carpal tunnel syndrome usually starts with a tingling (pins and needles) or numbness, particularly in the thumb, index finger and middle finger. There may also be general discomfort in the wrist or arm, and slight weakness of the hand grip. Symptoms may wake you up at night, but they may also occur during the day. For instance, you may notice symptoms while you are driving or holding a newspaper.

See your doctor or physiotherapist if:

  • your symptoms are getting worse or aren’t going away with self-care
  • your symptoms continue to interfere with your sleep or your normal activities
  • you notice wasting of your hand muscles at the base of the thumb.

If you leave the condition untreated while symptoms get worse, permanent nerve and muscle damage can occur.

How is carpal tunnel syndrome diagnosed?

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

Other tests that the doctor may recommend can include:

  • Blood tests: if your doctor suspects an underlying condition, such as diabetes, rheumatoid arthritis or underactive thyroid.
  • Nerve conduction study: to find out if there are changes in the function of the nerves in the wrist and hand.
  • 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 as carpal tunnel syndrome, you and your health professional will make a treatment plan.

How is carpal tunnel syndrome treated?

Treatment for carpal tunnel syndrome depends on the severity of your symptoms and how long you have had them. Treatment will also depend on whether you have other conditions that may need further treatment such as arthritis, diabetes or another injury). In some cases, symptoms improve within a few weeks.

Self-care

Self-care is the first option, particularly if the symptoms are mild and during pregnancy. 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
  • using a removable wrist splint to keep the wrist in a neutral angle. You may be use a splint during the night or the day, depending on when your symptoms are worst. Such splints can often be bought over the counter from a pharmacy.

Other treatments

If self-care does not relieve symptoms within a few weeks talk to your doctor or physiotherapist. There are a range of treatments available.

  • Physiotherapy or hand therapy may be helpful for some people, and can include improving mobility of the wrist bones, improving flexibility of soft tissues in the arm, and strengthening exercise. Physiotherapists can also provide advice regarding strategies and solutions for activities at work, such as when writing on a keyboard.
  • Pain relief medication such as paracetamol may provide relief when used in addition to self care, splint and therapy. Read more about paracetamol.
  • The doctor may offer cortisone injections, that can also provide short-term relief. Read more about cortisone injections.

It is also important to manage any underlying causes, such as diabetes. Loosing weight, if you are over-weight or obese, is likely to reduce the symptoms.

Treatment for severe symptoms

If symptoms persist despite self-care and the above treatment, and if there is wasting of hand muscles, surgery may be needed. Surgery will relieve pressure on the trapped nerve and aims to prevent any permanent nerve damage. Your doctor will be able to discuss the most suitable method of surgery with you.

Learn more

The following links have more information about carpal tunnel syndrome. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Carpal tunnel syndrome Arthritis Research, UK 
Carpal tunnel syndrome
Mayo Clinic, US 
Carpal tunnel syndrome NHS Choices, UK

Reviewed by

Gisela Sole is Associate Professor at the School of Physiotherapy, University of Otago, Dunedin. She is a physiotherapist, currently focusing on education and research which explores optimal management for individuals with musculoskeletal pain and injury, with special interest in persistent shoulder pain and knee injuries.
Credits: Health Navigator Editorial team. Reviewed By: Associate Professor Gisela Sole, School of Physiotherapy, University of Otago Last reviewed: 07 Feb 2019