Carpal tunnel syndrome (CTS) is caused by a pinched nerve in the wrist. (1)
The carpal tunnel is a narrow passageway on the palm side of the wrist. One of the main nerves in the hand — the median nerve — passes through this space in the wrist on its way to the hand. (1)
The median nerve runs from the neck down through the arm to the hand. It controls the muscles at the base of the thumb. It also carries signals about sensation from the thumb, index, long, and ring fingers to the brain. (1)
Carpal tunnel syndrome happens when the carpal tunnel becomes narrowed or when the tissues around the tendons passing through the carpal tunnel become swollen, putting pressure on the median nerve. (1)
Signs and Symptoms of Carpal Tunnel Syndrome
At first, symptoms of carpal tunnel syndrome tend to be subtle or may come and go. Pain and other sensations begin gradually and worsen over time. (1)
You may experience the following symptoms: (2)
Tingling or Numbness Usually you will notice tingling and numbness in your thumb and index, middle, or ring fingers — your little finger is not affected. You may also feel a shock-like sensation in these fingers that may travel from your wrist up your arm.
You may notice these symptoms particularly when you are driving, talking on the phone, or holding a newspaper.
Weakness You may experience weakness in your hand. This weakness or numbness may cause you to drop objects.
Learn More About Signs and Symptoms of Carpal Tunnel Syndrome
Causes and Risk Factors of Carpal Tunnel Syndrome
Sometimes the cause of carpal tunnel syndrome is obvious. For instance, a wrist sprain or break could narrow the carpal tunnel passage and pinch the median nerve. (3) Or rheumatoid arthritis could cause painful inflammation in the wrist joint. (2)
Many times, there is no single cause, or it’s not clear how or why the median nerve got pinched.
Many cases of carpal tunnel are due to a combination of factors. (3)
There are a number of risk factors that may increase your chances of developing carpal tunnel syndrome.
Risk factors for carpal tunnel syndrome include:
- Female Gender Women are 3 times as likely to develop carpal tunnel syndrome as men. (3)
- Pregnancy Hormonal changes during pregnancy can cause wrist swelling that pinches the median nerve, especially during the last few months. (4)
- Menopause Hormonal changes around the transition to menopause may put women at greater risk of developing carpal tunnel syndrome. (2)
- Heredity Traits that can run in families — differences in wrist anatomy that create a tighter passageway, for instance — may predispose some people to developing carpal tunnel syndrome. (1)
- Obesity Being obese is a risk factor for carpal tunnel syndrome. (2)
- Rheumatoid Arthritis Rheumatoid arthritis is an inflammatory condition that can cause swelling and inflammation around the tendons in your wrist and put pressure on the median nerve. (2)
- Diabetes Nerve damage caused by diabetes may make some people more susceptible to the condition. (2)
- Other Medical Conditions Certain conditions, such as menopause, hypothyroidism, kidney failure, and lymphedema, may increase your chances of carpal tunnel syndrome. In addition, some studies have shown a link between carpal tunnel syndrome and the use of anastrozole (Arimidex), a drug used to treat breast cancer. (2)
- Repetitive Hand and Wrist Use There’s some evidence that repeating the same hand and wrist motions for a prolonged period of time may irritate the wrist tendons and put pressure on the median nerve. (2)
People used to think that carpal tunnel syndrome was caused by too much use of computer keyboards. Some evidence suggests that mouse use, not keyboard use, may be associated with carpal tunnel syndrome. However, there has not been consistent evidence to support extensive computer use as a risk factor for carpal tunnel syndrome. (2)
But how you use your hands at work may play a role. Workplace factors may contribute to existing pressure or damage to the median nerve. Those who perform assembly line work — such as manufacturing, sewing, and meatpacking — may be at higher risk of developing CTS than data-entry personnel. (3)
How Is Carpal Tunnel Syndrome Diagnosed?
In order to properly diagnose carpal tunnel syndrome, your doctor will review your medical history, perform a physical exam, and use diagnostic imaging tests.
A review of your medical history, including your symptoms and general health, can help rule out other medical problems or related conditions that might be causing wrist and hand pain. (3)
A physical exam of your hands, wrists, arms, shoulders and neck can alert your doctor to any signs of nerve damage.
Diagnostic imaging tests for CTS may include electrodiagnostic tests that assess nerve function. These tests can rule out other nerve conditions. These tests include: (3)
- Nerve Conduction Studies (NCS) Small electrodes taped to the skin send a small shock through the median nerve to measure its electrical activity. If the electrical impulse slows at the carpal tunnel, it indicates that the nerve is pinched.
- Electromyogram (EMG) This test, involving placing small needles into various muscles, can show whether there is any muscle or nerve damage by measuring tiny electrical impulses in the hand muscles.
Other diagnostic tests that may be performed include: (1)
- X-rays can help rule out arthritis or bone fracture and can allow your doctor to see abnormalities in bone structure that could be responsible for your wrist pain.
- An ultrasound is generally only used to rule out a mass or a lesion, and it can be helpful in showing abnormalities of the median nerve and the ligaments and tendons of the wrist. (1)
Prognosis of Carpal Tunnel Syndrome
For most people, carpal tunnel syndrome will worsen over time without some form of treatment. The process may be gradual, but it’s important to be evaluated and diagnosed early on by your doctor, or your condition could lead to permanent damage. (1)
Sometimes, carpal tunnel syndrome can improve with minimal intervention. If you have mild to moderate symptoms that have come and gone for less than 10 months, splinting and other conservative treatments can sometimes alleviate symptoms. (5)
If your case is more severe and chronic, surgery may be an option for you. You can expect relief fairly quickly from many symptoms, including tingling sensations in the hand that wake you up at night following the procedure. (6) Numbness may take longer to be relieved, even up to three months. Surgery has a very high short-term success rate of over 90 percent. However, it has been found in different trials that the long-term success rate is lower than initially thought (approximately 60 percent at five years following surgery).
In long-standing cases where there’s been severe loss of feeling or muscle wasting around the base of the thumb, recovery may be slow, and for some patients complete recovery may not be possible. (1)
Duration of Carpal Tunnel Syndrome
Without proper treatment, one could potentially have carpal tunnel syndrome for months or years.
Symptoms generally do not resolve on their own without some form of intervention.
If your carpal tunnel syndrome is due to hormonal changes and swelling caused by pregnancy, it typically goes away on its own after pregnancy and does not require surgery. (1)
Treatment and Medication Options for Carpal Tunnel Syndrome
Carpal tunnel syndrome is treated in two ways: nonsurgically and with surgery. Less severe cases are generally treated with therapeutic or medical treatment.
Surgery may be necessary when your symptoms are severe or if they don’t respond to other treatments.
Most people can get relief from carpal tunnel symptoms with nonsurgical treatment. (7)
Nonsurgical treatment options include:
- Carpal Tunnel Brace Wrist splinting is often the first line of treatment for CTS. Wearing a splint or brace around your wrist keeps your wrist in a neutral or straight position, and this can help reduce pressure on the median nerve. Wearing a brace at night can keep your wrist from bending while you sleep. It can also be helpful to wear a brace during daytime activities that aggravate your symptoms. (1)
- Over-the-Counter (OTC) Medicine OTC pain medication, including ibuprofen (Advil), naproxen (Aleve), or aspirin (Vazalore), can temporarily relieve pain and inflammation, but they won’t treat the underlying cause and are typically limited to short-term use. (3)
- Steroid Injections Corticosteroid injections to the wrist and hand may provide some temporary relief. (1)
If your pain doesn’t go away after trying more conservative treatment options like splints or steroid injections, or if your medial nerve has been damaged, your doctor may recommend surgery.
The procedure, called carpal tunnel release surgery, involves cutting the ligament around the wrist to relieve pressure on the medial nerve. After the surgery, the ligament grows back together leaving more room in the carpal tunnel for nerves and tendons to pass through. (1)
There are two ways to perform carpal release surgery: (1)
- Open Carpal Tunnel Release Your surgeon makes a small incision to open your wrist and cut the carpal tunnel ligament.
- Endoscopic Carpal Tunnel Release Your surgeon makes two small incisions, one on the palm and one on the wrist. A tiny camera is inserted in one incision. Your doctor uses the camera to guide a small knife (inserted via the other incision) that cuts the ligament.
Complementary and Integrative Approaches
Acupuncture and chiropractic care have benefited some individuals, and some research supports their use with few adverse effects. (16,17) Yoga has been shown to reduce pain and improve grip strength among those with carpal tunnel syndrome. (3)
Carpal tunnel exercises, particularly when combined with other treatments like wrist splints or behavioral changes (e.g., making sure not to overextend your wrist while typing), can help relieve symptoms of mild to moderate CTS. (8)
Learn More About Treatment for Carpal Tunnel Syndrome
Prevention of Carpal Tunnel Syndrome
It’s not clear whether carpal tunnel syndrome can be prevented.
Since the condition can be caused by so many activities in daily life, prevention is challenging.
However, there are a few things you could consider doing that might decrease your chances of developing CTS. (6)
- Sleeping with your wrists held straight
- Avoiding flexing (curling) and extending your wrists repeatedly
- Decreasing repetitive or strong grasping with the wrist in a flexed position
- Taking frequent rest breaks from repetitive activities
- Staying in a healthy weight range
Complications of Carpal Tunnel Syndrome
Untreated carpal tunnel syndrome can lead to permanent damage, including the inability to use your hands and fingers properly. In addition, the muscles in the hands may shrink, leading to an increase in pain and muscle cramps. (6)
Sometimes carpal tunnel syndrome can cause pain or numbness in the lower part of the arm, as well. These symptoms usually start gradually and worsen over time. (1)
Seeking treatment early is very important.
Research and Statistics: How Many People Have Carpal Tunnel Syndrome?
Carpal tunnel syndrome is a common nerve condition. It affects between 4 and 10 million Americans. (11)
Carpal tunnel syndrome typically appears in middle-aged and older adults. It occurs less often in younger people.
CTS most often affects people between ages 40 and 60. In more than one-half of cases, both hands are affected. However, the severity may vary between hands. When one hand is affected, it is most often the hand used for writing (dominant hand). (12)
Related Conditions and Causes of Carpal Tunnel Syndrome
There are a few related disorders that can cause carpal-tunnel-like symptoms. These typically involve a pinched nerve elsewhere in the arm or neck and are ruled in or out by a neurologist, typically on physical examination or with EMG and NCS.
Related conditions include:
- Cervical Radiculopathy This condition occurs when a nerve in the neck gets pinched or irritated by the cervical vertebrae (the bones directly below the skull that make up the neck). It can cause tingling or loss of sensation in the hand and fingers and weakness in the arm. (13)
- Thoracic Outlet Syndrome Thoracic (TOS) Thoracic outlet syndrome is a group of disorders that occur when a nerve or blood vessel gets pinched in the area where the neck meets the collarbone. It can cause numbness and tingling or feeling of pins and needles in the upper arm, forearm, or hand. (14)
- Pronator Teres Syndrome (PTS) PTS is caused by the compression of the median nerve further up the arm near the elbow. It shares similar symptoms with carpal tunnel syndrome, but there’s usually some pain or tenderness when pressing on the underside of the forearm, near the elbow. (15)