Carpal Tunnel Syndrome: Numb Fingers at Night, Causes and Treatment
Why the thumb, index and middle fingers go numb at night, how carpal tunnel syndrome is diagnosed, and when a wrist splint, injection or surgery is the right treatment.
Key takeaways
- Carpal tunnel syndrome is pressure on the median nerve at the wrist. It causes tingling and numbness in the thumb, index, middle and half the ring finger.
- Symptoms are typically worse at night or on waking, and shaking the hand often relieves them.
- It is more common in women, in pregnancy, and in people with diabetes or an underactive thyroid, so these are worth checking.
- A night wrist splint helps most mild cases. Steroid injections help many. Surgery is a short procedure for severe or persistent cases, especially with thumb weakness.
Waking at night with a numb, tingling hand and shaking it until the feeling returns is one of the commonest hand complaints doctors see. It is usually carpal tunnel syndrome, and it is very treatable, especially when caught before the nerve is damaged. This guide explains the pattern, the tests and the treatments.
Quick answer
Carpal tunnel syndrome is a squeezed nerve at the wrist. It causes numbness and tingling in the thumb, index, middle and half the ring finger, worse at night and eased by shaking the hand. It is commoner in women, pregnancy, diabetes and thyroid disease. A night splint helps most mild cases; injections and a short surgery help more severe ones.
What is the carpal tunnel?
At the front of the wrist, the bones form a channel roofed by a tough ligament. Through it pass the tendons that bend the fingers and the median nerve, which supplies feeling to the thumb, index, middle and half the ring finger, and some thumb muscles. When pressure in the tunnel rises, the nerve is squeezed.
Typical symptoms
Tingling, burning or numbness in those fingers, sparing the little finger, which is supplied by a different nerve. Symptoms often wake you at night or are there on waking, and shaking or flicking the hand relieves them. Later, the hand may feel clumsy, grip weakens, you drop things, and the muscle at the base of the thumb can waste. Numbness of the little finger or the whole hand suggests a different cause; see the tingling and numbness guide.
Who gets it
Women more than men. Pregnancy, through fluid retention. Diabetes and an underactive thyroid, both worth testing for; see the HbA1c guide and the thyroid test guide. Rheumatoid arthritis, previous wrist fractures, obesity, and sometimes work that involves forceful, repeated wrist movement or vibrating tools.
How it is diagnosed
Usually from the history and examination. Tapping over the nerve at the wrist (Tinel’s sign) or holding the wrists bent for a minute (Phalen’s test) may reproduce the tingling. A nerve conduction study measures how well the nerve carries signals; it confirms the diagnosis, shows how severe it is, and rules out a pinched nerve in the neck, which can mimic it. Ultrasound of the wrist is sometimes used.
Treatment, from mildest to most definitive
| Treatment | Best for |
|---|---|
| Night wrist splint holding the wrist straight | Mild to moderate symptoms; often the first step |
| Treating the cause: diabetes, thyroid, pregnancy | Everyone with an identifiable trigger |
| Steroid injection into the carpal tunnel | Moderate symptoms; relief may last months |
| Carpal tunnel release surgery | Severe or persistent symptoms, constant numbness, thumb muscle wasting |
Painkillers do not treat the nerve compression. Surgery is a short procedure, usually done as a day case under local anaesthetic.
Do not wait too long if you notice
Constant numbness that no longer comes and goes, weakness of the thumb, or wasting of the muscle at the base of the thumb. These mean the nerve is being damaged, and recovery after surgery is less complete the longer this continues.
When to see a doctor
See a doctor for tingling or numbness that keeps returning, wakes you at night or is getting worse, for any hand weakness, or for symptoms in pregnancy that do not settle. Sudden numbness of one side of the body, with facial droop or speech difficulty, is not carpal tunnel: call 108 or 112.
Frequently asked questions
What are the first signs of carpal tunnel syndrome?
Tingling, pins and needles or numbness in the thumb, index and middle fingers, often waking you at night or present on waking, and relieved by shaking or flicking the hand. Later, grip may weaken and you may drop things.
Why is carpal tunnel worse at night?
Many people sleep with their wrists bent, which raises pressure inside the carpal tunnel, and fluid shifts while lying down add to it. A splint that holds the wrist straight at night often relieves symptoms for this reason.
Will carpal tunnel go away on its own?
Mild cases sometimes settle, especially when a trigger is removed, and carpal tunnel in pregnancy often improves after delivery. Persistent or worsening symptoms, particularly with weakness or constant numbness, need treatment to prevent lasting nerve damage.
Is carpal tunnel surgery safe?
Carpal tunnel release is a common, short operation, usually under local anaesthetic, that cuts a ligament to relieve pressure on the nerve. Most people get good relief of night symptoms quickly; numbness and strength recover more slowly, and recovery is less complete if the nerve was badly damaged beforehand.
Can mobile phone and laptop use cause carpal tunnel?
Long periods with the wrist bent can aggravate symptoms, but the evidence that typing or phone use causes carpal tunnel syndrome is weaker than commonly believed. Genetics, anatomy, diabetes, thyroid disease and pregnancy play larger roles.
Sources
Dr. Garima Panse is a medical doctor who writes plain-language guides for Indian readers on skin health, heart health, brain and nerves, medical imaging and everyday medicine. Every guide lists its sources, shows the date it was last reviewed, and says when to see a doctor in person.
This guide is for general education and reflects the evidence available on the last reviewed date. It is not a diagnosis, a prescription or a substitute for seeing a doctor who can examine you. If you have symptoms that worry you, or the guide tells you to see someone, please do. Full disclaimer.