A person with carpal tunnel syndrome feels tingling, burning, or itching numbness in the palm of the hand and the fingers, especially the thumb and index finger.
Sensations to the palm of the hand, as well as the thumb and three other fingers (not the little finger) are controlled by the median nerve..
The median nerve also controls some of the small muscles that allow the thumb and fingers to move.
The carpal tunnel, also known as the carpal canal, is a passage of bones and ligaments at the base of the hand. The median nerve and tendons are also in the carpal tunnel. The carpal tunnel can sometimes narrow as a result of irritated tendons or some other swelling, this puts pressure on the median nerve.
Pressure on the median nerve can lead to pain, numbness and weakness in the hand and wrist, which may make its way up into the arm.
According to the National Institute of Neurological Disorders and Stroke1, carpal tunnel syndrome is the "most common and widely known of the entrapment neuropathies in which the body's peripheral nerves are compressed or traumatized."
CTS (carpal tunnel syndrome) is one of the most common conditions affecting the nerves of the hand. It is estimated that almost 5% of women and 3% of men have CTS. American Family Physician2 estimates that from 3% to 6% of adults in the general population suffer from carpal tunnel syndrome. Most cases of CTS develop in people who are between 45-64 years of age.
CTS is not a life-threatening condition, but it can negatively affect lifestyle if left untreated. In worst case scenarios, the median nerve can become severely damaged and result in total loss of movement within the affected hand.
What are the signs and symptoms of Carpal Tunnel Syndrome?A symptom is something the patient feels and describes, such as pain, while a sign is something others can detect, such as a skin rash.
Carpal tunnel syndrome symptoms tend to develop gradually over time.
Most patients say their first symptoms appeared during the night, or on waking up in the morning. According to The Cleveland Clinic3, patients commonly feel the need to "shake out" their hands when they wake up.
The three main symptoms associated with CTS are:
Sometimes the unpleasant sensations extend to the rest of the hand and even into the forearm.
As CTS gets worse, symptoms may persist during the day. The person may lose grip strength and find it harder to form a fist or grasp small objects. Opening a bottle of soda, doing up your buttons, or typing on a keyboard, tasks that used to be easy, become a challenge.
If left untreated, the muscles at the base of the thumb may whither away. The ability to tell hot from cold with thumb and finger may be lost.
Symptoms tend to get worse or emerge after using the affected hand. The sensation of tingling, burning and pain may get worse if the arm or hand has been in the same position for a long time.
Video - Carpal Tunnel Syndrome, University of WarwickThe video, from the University of Warwick, England, explains the complex anatomy related to carpal tunnel syndrome.
What are the causes of Carpal Tunnel Syndrome?There can be several causes of carpal tunnel syndrome. It is a disorder that becomes much more likely if the person has to frequently use extremes of wrist motion and vibration, and repeatedly use their finger with high force.
Sometimes no cause for CTS can be found (idiopathic).
The most common causes of carpal tunnel syndrome are:
- A cyst in the carpal tunnel
- A tumor in the carpal tunnel
- Edema - fluid retention. That is why pregnant women are more susceptible to CTS
- Hypothyroidism - underactive thyroid gland
- Swelling (inflammation) around the tendons
- Wrist dislocation
- Wrist fracture
- Obesity combined with wrist shape - a study showed that some obese people are more likely to develop CTS. The researchers, from Gaziosmanpasa University in Turkey, say the cause is a combination of wrist shape and obesity, because when their obese participants lost weight they continued suffering from CTS.
Team leader, Dr. Yuksel Kaplan, believes that people with a genetic profile for obesity and certain wrist shapes are more likely to develop CTS, i.e. obesity alone is not the cause.
- Degenerative and rheumatoid arthritis
- Overactivity of the pituitary gland
- Structural problems in the wrist joint
- Using vibrating hand tools repeatedly
- Work stress
- Breast cancer treatment - many postmenopausal women on aromatase inhibitor drugs for breast cancer experience carpal tunnel syndrome. A fingertip test can help determine a patient's risk.
An article in the Journal of General Internal Medicine4 reported that although the main non-occupational risk factor for carpal tunnel syndrome is inflammatory arthritis, untreated hypothyroidism and diabetes also appear to increase the risk considerably.
A team of British experts listed the following nonoccupational risk factors associated with carpal tunnel syndrome in the Journal of Hand Surgery (European Volume)5:
- previous wrist fracture
- rheumatoid arthritis
- osteoarthritis of the wrist and carpus
- diabetes and the use of insulin, metformin, sulphonylureas, and thyroxine
The National Institute of Neurological Disorders and Stroke6 says that CTS is three times more likely to occur in assemblers than data-entry personnel.
The Canadian Centre for Occupational Health and Safety7 lists the following occupations as risk factors for carpal tunnel syndrome:
- Farmer - milking cows
- Assembly worker - using air-power hand tools
- Assembly-line worker - handling objects on the conveyor belt
- Check-out cashier - using laser scanners
- Factory/farm/mechanic workers - wearing tight gloves
- Gardener - weeding by hand
- Homemaker (housewife) - knitting
- Locksmith - turning keys
- Mechanic - using screwdrivers, pushing down ratchets
- Musician - using the bow (stringed instruments)
- Office workers - using mouse and keyboard
- Painter - repeated use of spray guns
- Poultry/meat processing worker - de-boning and cutting
- Stablehand/painter/carpenter - pressing tools into the palm of the hand
Diagnosing Carpal Tunnel Syndrome
A primary care physician (general practitioner, family doctor) is usually able to diagnose carpal tunnel syndrome.
The doctor will ask the patient about symptoms and examine the hand and wrist, looking for signs of weakness in the muscles around the thumb. The patient's ability to use his/her hand and wrist will also be assessed.
- Tinel's test (Tinel's sign) - the doctor taps the median nerve at the wrist lightly to see whether the patient feels numbness or tingling in one or more of the fingers. The UK National Health Service8 says that this test may be helpful, but is not reliable.
- Phalen's test (wrist-flexion) - the patient is asked to press the backs of the hands against each other so that the wrist is bent. If within one minute there is tingling or numbness it could indicate damage to the median nerve.
- Nerve conduction study - electrodes are placed on the hand and wrist. Small electric shocks are applied. The test measures how quickly the nerves transmit the impulses to the muscles.
- Electromyography - a fine needle is inserted into the muscle. The doctor views electrical activity on the screen and can determine whether there is any median nerve damage, and if so, how severe it is.
- Blood tests - blood tests may be used to determine whether the patient has an underlying condition related to carpal tunnel syndrome, including hypothyroidism, rheumatoid arthritis or diabetes.
- Imaging scans - the doctor may order an ex-ray to determine whether there is a fracture or some other disorder, such as rheumatoid arthritis. An ultrasound scan may also be recommended to check the structure of the median nerve. Studies have found that MRI scans are not useful in diagnosing carpal tunnel syndrome.
What are the treatment options for Carpal Tunnel Syndrome?
The aim of treatment for carpal tunnel syndrome is to reduce pressure on the median nerve, thus relieving the symptoms and possibly stopping the syndrome's progression.
Patients with just mild symptoms may find their condition improves without any treatment within a few months. This is especially the case with people aged 30 or less and pregnant mothers.
Things you can do yourself
Resting the hand and wrist - the more you rest your hand and wrist the greater the chance of relieving the symptoms.
Cold compress - some patients find that placing an ice pack helps during "flare ups". Make sure you do not apply ice directly onto skin.
Control the triggers - if your CTS is caused by repetitive hand movements, make sure you have plenty of break periods so your hand and wrist have time to rest and recover. An occupational therapist might be able to teach you how to carry out those tasks differently.
Most patients with mild symptoms will notice an improvement in their symptoms within four weeks.
Some people wear a wrist splint during the day. However, there is a risk you may find they interfere with your daily activities.
Wrist splints can be bought OTC (over-the-counter) at pharmacies. They can also be ordered online. Ask a pharmacist or your doctor about them.
Medications for carpal tunnel syndrome
Corticosteroid injections - The doctor may recommend steroid injections; these are applied directly into the carpal tunnel. Initially, the patient may experience greater pain, but after a couple of days should notice significant improvement.
If the condition responds well to a corticosteroid injection, but symptoms return after a few months, the patient may be advised to take another one.
Corticosteroids are available in oral tablet form. However, most doctors say injections are more effective.
Non-steroidal anti-inflammatory drugs (NSAIDs) - such as aspirin or ibuprofen may help in short-term pain relief.
Studies have indicated that NSAIDs only help if there is an underlying inflammatory condition causing the CTS.
Researchers reported in the journal Clinical Rehabilitation10 that "There is: strong evidence on efficacy of local and oral steroids; moderate evidence that vitamin B6 is ineffective and splints are effective and limited or conflicting evidence that NSAIDs, diuretics, yoga, laser and ultrasound are effective, whereas exercise therapy and botulinum toxin B injection are ineffective."
Surgery for carpal tunnel syndrome
In cases of severe carpal tunnel syndrome, where treatments have not been effective and symptoms have lasted for at least six months, the doctor may recommend surgery.
CTS surgery is known as "carpal tunnel release surgery" or "carpal tunnel decompression". It is an outpatient procedure, i.e. the patient does not stay in hospital after the operation.
The carpal ligament (roof of the carpal tunnel) is cut, thus reducing pressure on the median nerve.
A survey carried out by the National Health Service11 asked 6,000 patients who underwent carpal tunnel release surgery" how pleased they were with the result. About 50% said the procedure had cured them, and a further 25% said their symptoms improved considerably.
The National Health Service warns that, as with any type of surgery, there is always a risk of complications, including infection, post-operative bleeding, nerve injury, and scarring.
Preventing Carpal Tunnel SyndromeThere are several measures you can take to reduce your risk of developing carpal tunnel syndrome.
Unfortunately, most people who have never had CTS ignore them.
- Don't grip so hard - most of us use more force than we need when performing manual tasks.
- Don't overbend your wrist - do not bend your wrist all the way down or up, go for a middle position. Sleep and work with your wrists straight. Avoid repeated flexing and extending of your wrists.
- Posture - wrong posture can lead to maneuvers that place undue strain on the wrist and hands.
- Redesign your workstation - good workstation design reduces unnatural and awkward wrist positions. Talk to your employer about this.
- Remember to rest - taking frequent breaks when performing a task will help protect you from the long-term effects, especially if it is a task you have to do frequently.
- Temperature - a cold environment (cold hands) can increase the risk of developing carpal tunnel syndrome. If you are in a working environment and your hands are cold, consider wearing gloves.
- Treat an underlying condition/illness - if you have diabetes, good glucose control will help prevent several complications.