Numb fingers at night: carpal tunnel syndrome explained

Waking at night with numb, tingling fingers is a common sign of carpal tunnel syndrome. It happens when a nerve at the wrist, the median nerve, is squeezed. It usually affects the thumb, index, middle and ring fingers. A night splint often helps, and a short operation can release the pressure if other treatment does not work.

What the carpal tunnel is

The carpal tunnel is a narrow passage on the palm side of the wrist. Its floor is made of small wrist bones and its roof is a tough band called the transverse carpal ligament. The median nerve runs through it, along with the tendons that bend the fingers. If the tissues inside swell, or the tunnel is naturally tight, the nerve gets squeezed.

How it feels

• numbness, tingling, burning or pins and needles in the thumb, index, middle and ring fingers
• symptoms that wake you at night, often eased by shaking or moving the hand
• symptoms when holding a phone, driving or reading with the wrist bent
• pain or tingling that spreads up the forearm
• a weak grip, clumsiness, or dropping things
• difficulty with fine tasks such as doing up buttons

The little finger is usually not affected, because a different nerve supplies it. Symptoms often start slowly and come and go. Over time they can become more frequent and last longer.

Why it is worse at night

Many people sleep with their wrists curled. That position raises the pressure inside the carpal tunnel. This is why numbness so often wakes people in the early hours, and why a splint that keeps the wrist straight at night is one of the first treatments.

Who gets it

It is more common in women and with age. You are more at risk if you:

• are pregnant
• are overweight
• often bend your wrist or grip hard, for example using vibrating tools
• have diabetes, rheumatoid arthritis or a thyroid problem
• have a close family member with it
• have injured your wrist before

How it is diagnosed

Often the history and an examination are enough. The doctor may:

• tap over the nerve at the wrist to see if it sends tingling into the fingers
• hold your wrist bent for a short time to see if symptoms appear
• test feeling in your fingertips
• check the strength of the muscles at the base of the thumb, and look for wasting there

If the diagnosis is not clear, or to judge how severe it is, you may have a nerve conduction study, which measures how well signals travel along the nerve. An ultrasound can show the nerve. An X-ray or MRI is used when another cause is suspected, such as arthritis or an old fracture.

Treatment without surgery

Early, mild carpal tunnel syndrome often settles without an operation.

• A wrist splint at night. It keeps the wrist straight while you sleep. It may take up to 6 weeks to help.
• Changing activities. Cut down on gripping hard, vibrating tools and long spells with the wrist bent. Small changes to a desk or workstation can help.
• Painkillers. Paracetamol or ibuprofen can ease pain for a short time, but they do not treat the cause.
• Hand and nerve gliding exercises. These help some people.
• A steroid injection. It reduces swelling around the nerve and often eases symptoms, but the effect may wear off after a few months.

When it starts in pregnancy, it often improves after the baby is born.

Carpal tunnel release surgery

Surgery is considered when symptoms keep getting worse, when other treatments have not helped or only helped for a short time, or when there is constant numbness or wasting of the thumb muscles. In that last case surgery aims to prevent lasting nerve damage.

In a carpal tunnel release, the surgeon cuts the ligament that forms the roof of the tunnel. This makes more room for the nerve. It is usually done under local anaesthetic as a day case, and the operation itself takes about 20 minutes. It can take about a month to get back to normal activities, and longer for grip strength to return fully.

Read more about hand surgery in Dubai.

Other causes of numb fingers

Not every numb hand is carpal tunnel syndrome. A trapped nerve in the neck, pressure on a nerve at the elbow, and nerve damage from diabetes can all cause numbness. Which fingers are affected, and whether the neck or elbow is involved, helps the doctor tell them apart.

When to see a doctor

See a doctor if numbness and tingling keep coming back, are getting worse, or do not improve with a splint and rest. Go sooner if your hand feels weak, you keep dropping things, or the muscles at the base of your thumb look thinner. Treated early, the nerve has a better chance to recover.

Sudden numbness or weakness in an arm, especially with a drooping face or slurred speech, can be a stroke. This is an emergency: call 998 straight away.