Carpal tunnel syndrome

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

Key points

  1. Carpal tunnel syndrome usually starts with a tingling or numbness in your hands and fingers, and becomes increasingly painful.
  2. It is 5 times more common in women than in men and occurs most often in people aged between 30 and 60. 
  3. It also occurs more often during pregnancy and in people with certain long-term conditions. 
  4. It may be brought on by repetitive activities at work, sport or other recreational activities.
  5. Treatment 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 the median nerve in the carpal tunnel.

The carpal tunnel is a narrow space inside your wrist that is surrounded by bone and ligament. This tunnel protects the finger tendons, nerves and blood vessels where they pass from your forearm into your hand.

  • With carpal tunnel syndrome, the carpal tunnel swells and compresses the median nerve.
  • This could be caused by thickening of the tendon sheaths, which reduces the amount of space inside the carpal tunnel.
  • As a result, the median nerve may be compressed, and you then feel pain and tingling, particularly on the thumb side of your palm, your thumb and your fingers.

There are a number of possible causes of this happening.

Possible causes of carpal tunnel syndrome

  • Pregnancy: Up to about 50% of pregnant women develop hand and finger pain, possibly due to fluid retention in the carpal tunnel.
  • Injury to your wrist.
  • Other health conditions, such as diabetes, which can make nerves more sensitive, and rheumatoid arthritis, which can cause inflammation of the tendons in your wrist.
  • Repetitive work with your hand.
  • Obesity.
  • Various types of hormonal conditions.
  • A family history of carpal tunnel syndrome. This is because your genes influence things like the anatomical shape of your carpal tunnel.

What are the symptoms of carpal tunnel syndrome?

Carpal tunnel syndrome usually starts with a tingling (pins and needles) or numbness, particularly in your thumb, index finger and middle finger. There may also be general discomfort in your wrist or arm, and slight weakness of your 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 your 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 they want to rule out other conditions that have similar symptoms.

Other tests that your doctor may recommend can include the following:

  • 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. IN all cases, it aims to reduce the pressure in the carpal tunnel space. 

Self-care

Self-care is the first option, particularly if your symptoms are mild or occur during pregnancy. You may be able to help ease discomfort by:

  • taking frequent breaks to rest your hands
  • modifying your wrist posture
  • avoiding activities or movements that make symptoms worse
  • avoiding prolonged, repetitive or strong gripping of objects
  • avoiding extreme bending of your wrist
  • avoiding gripping of equipment or tools that are narrow and slippery as they require more force to hold onto - you may need to get wider and less slippery equipment or tools
  • applying cold packs to reduce any swelling
  • using a removable wrist splint to keep your wrist straight – use during the night or the day, depending on when your symptoms are worst. Splints can often be bought over the counter from a pharmacy.
Note: Squeezing a ball is not helpful for this condition.

Other treatment

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. It can include improving mobility of your wrist bones, improving flexibility of soft tissues in your arm and strengthening exercises.
  • Physiotherapists can also provide advice regarding strategies and solutions for activities at work, such as when using a keyboard.
  • Pain relief medication such as paracetamol may provide relief when used in addition to self-care, a splint and therapy. Read more about paracetamol.
  • Your doctor may offer cortisone injections, which can also provide short-term relief. Read more about cortisone injections.

It is also important to manage any underlying causes, such as diabetes. Losing weight, if you are overweight 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 your hand muscles, you may need surgery. Surgery relieves 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 Mayo Clinic, US 
Carpal tunnel syndrome NHS Choices, UK
Carpal tunnel syndrome OrthoInfo, US

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 that explores optimal management for individuals with musculoskeletal pain and injury, with special interest in persistent shoulder pain and knee injuries.
Miranda Bűhler is a physiotherapist and hand therapist with 20 years’ clinical experience. She works at Southern District Health Board. Her clinical and research interests cover a wide range of post-traumatic and long-term conditions involving the hand and upper limb. She is currently completing her PhD at the University of Otago.
Credits: Health Navigator Editorial team. Reviewed By: Associate Professor Gisela Sole, School of Physiotherapy, University of Otago; Miranda Buhler, physiotherapist and hand therapist Last reviewed: 22 Apr 2020