What is carpal tunnel syndrome?

Carpal tunnel syndrome is caused by compression of the median nerve when it passes through the wrist. The median nerve carries the sense of touch to the thumb and most of the next 2 fingers, and controls movement for some of the hand muscles.

This nerve runs from the spinal cord down the arm then through the carpal tunnel — a narrow passageway in the wrist with just enough room for the tendons and nerves that pass through it. When the tendons become swollen or thickened, there is less space for the median nerve, and it can become compressed.

What are the symptoms of carpal tunnel syndrome?

The most common symptoms of carpal tunnel syndrome include:

• tingling or numbness in your fingers or the palm of your hand that feels like pins and needles, mainly in the thumb and next 2 fingers
• nerve pain in your wrist or hand, which can spread up your arm or down to your fingers
• weakness in your hands, making it hard to grip things
• swollen fingers

Symptoms are usually worse in the hand you use the most (your dominant hand), but the condition can affect both hands.

Over time, people with carpal tunnel syndrome might find that they slowly lose strength and movement in their hand and wrist. So it’s important to see your doctor if you think you may have carpal tunnel syndrome.

What causes carpal tunnel syndrome?

Carpal tunnel syndrome can be caused by anything that makes the nerves or tendons larger, or makes the tunnel that they run through smaller. This includes:

• a wrist or arm injury, such as a sprain or fracture
• activities that involve repetitive use (overuse) of the wrist and hand, including using vibrating tools
• rheumatoid arthritis and other joint disorders or connective tissue disorders
• tendonitis
• fluid retention during pregnancy or menopause
• a cyst or tumour in the carpal tunnel
• diabetes
• hypothyroidism
• abnormal growth of the hands (acromegaly)
• kidney disease with dialysis

Sometimes, carpal tunnel syndrome just happens without any obvious cause.

Women aged 40 to 60, pregnant women, people with arthritis, people who put on weight rapidly and people who use their hands repeatedly in their work are more at risk of developing carpal tunnel syndrome.

How is carpal tunnel syndrome diagnosed?

Your doctor will ask about your symptoms, then you may have further tests to see how quickly the median nerve passes messages through the carpal tunnel. Your doctor may also request blood tests to rule out other associated conditions, such as rheumatoid arthritis, or x-rays, particularly if you have injured or broken your wrist or have bone changes.

How is carpal tunnel syndrome treated?

Treatment for carpal tunnel syndrome depends on its cause.

Treatment options can include:

• treating a related medical condition that could be causing the symptoms
• wearing a wrist brace (also called a splint) to keep the wrist straight, especially at night
• ice, elevation, massage
• anti-inflammatory medicines to ease pain
• avoiding activities that cause symptoms
• physiotherapy
• corticosteroid injections into the wrist
• surgery