The condition is caused by the median nerve becoming compressed as it passes through the carpal tunnel, which is a narrow passageway on the palm side of your wrist. This nerve controls some movements of your thumb.

If the carpal tunnel becomes narrowed it can press on the median nerve, causing numbness, tingling and weakness in the hand and leading to increasing amounts of pain.

The condition can be caused by:

• Pregnancy – the symptoms often go away a few months after the baby is born.
• Certain health conditions such as diabetes, rheumatoid arthritis and hypothyroidism.
• Obesity.
• A wrist fracture or dislocation which narrows the carpal tunnel.
• Swelling due to arthritis.
• Chronic illnesses like diabetes which can damage the nerves.

It is more common in women than men which may be due to the smaller size of their carpal tunnel.

The symptoms may start off as periodic numbness or tingling in your hand or fingers, particularly in the morning when you wake up.

Over time, the numbness may become constant and you may start to experience burning in the palm of your hand near your thumb or close to your index and middle fingers.

The symptoms may be worse if you are holding your hands in one position, such as holding a steering wheel, and they may wake you up at night.

If the condition becomes severe you may lose grip strength due to muscle wastage and you may have worsening pain and cramps. You may start to lose feeling in your fingers and find it difficult to pinch due to a loss of strength and co-ordination in your thumb. If left untreated you may develop permanent muscle damage.

The condition is normally diagnosed by carrying out an examination during which the doctor may ask you to carry out certain movements to assess the feeling and strength in your hand.

You may be given an X-ray to rule out other problems and nerve conduction testing which evaluates the speed of signal transmission in the nerve.

Treatment will vary depending on the severity of the condition. For mild cases, it may help to relieve the symptoms if you wear a splint at night to keep your wrist immobilised and lessen pressure on the nerves.

A Hand Therapist may be able to recommend stretching and strengthening exercises. Anti-inflammatories or injections of corticosteroids can help to improve pain.

In the most severe cases, surgery may be an option. The aim is to relieve pressure by cutting the ligament that is pressing on the median nerve. It may be performed endoscopically (using keyhole surgery) through small incisions on your hand, or using open surgery.