Carpal tunnel syndrome is caused by pressure on the median nerve. The carpal tunnel is a narrow passageway surrounded by bones and ligaments on the palm side of your hand. When the median nerve is compressed, the symptoms can include numbness, tingling and weakness in the hand and arm.
The anatomy of your wrist, health problems and possibly repetitive hand motions can contribute to carpal tunnel syndrome.
Proper treatment usually relieves the tingling and numbness and restores wrist and hand function.
Carpal tunnel syndrome symptoms usually start gradually and include:
Tingling or numbness. You may notice tingling and numbness in your fingers or hand. Usually the thumb and index, middle or ring fingers are affected, but not your little finger. You might feel a sensation like an electric shock in these fingers.
The sensation may travel from your wrist up your arm. These symptoms often occur while holding a steering wheel, phone or newspaper, or may wake you from sleep.
Many people "shake out" their hands to try to relieve their symptoms. The numb feeling may become constant over time.
See your doctor if you have signs and symptoms of carpal tunnel syndrome that interfere with your normal activities and sleep patterns. Permanent nerve and muscle damage can occur without treatment.
Carpal tunnel syndrome is caused by pressure on the median nerve.
The median nerve runs from your forearm through a passageway in your wrist (carpal tunnel) to your hand. It provides sensation to the palm side of your thumb and fingers, except the little finger. It also provides nerve signals to move the muscles around the base of your thumb (motor function).
Anything that squeezes or irritates the median nerve in the carpal tunnel space may lead to carpal tunnel syndrome. A wrist fracture can narrow the carpal tunnel and irritate the nerve, as can the swelling and inflammation caused by rheumatoid arthritis.
Many times, there is no single cause of carpal tunnel syndrome. It may be that a combination of risk factors contributes to the development of the condition.
A number of factors have been associated with carpal tunnel syndrome. Although they may not directly cause carpal tunnel syndrome, they may increase the risk of irritation or damage to the median nerve. These include:
Anatomic factors. A wrist fracture or dislocation, or arthritis that deforms the small bones in the wrist, can alter the space within the carpal tunnel and put pressure on the median nerve.
People who have smaller carpal tunnels may be more likely to have carpal tunnel syndrome.
Sex. Carpal tunnel syndrome is generally more common in women. This may be because the carpal tunnel area is relatively smaller in women than in men.
Women who have carpal tunnel syndrome may also have smaller carpal tunnels than women who don't have the condition.
Workplace factors. Working with vibrating tools or on an assembly line that requires prolonged or repetitive flexing of the wrist may create harmful pressure on the median nerve or worsen existing nerve damage, especially if the work is done in a cold environment.
However, the scientific evidence is conflicting and these factors haven't been established work as direct causes of carpal tunnel syndrome.
Several studies have evaluated whether there is an association between computer use and carpal tunnel syndrome. Some evidence suggests that it is mouse use, and not the use of a keyboard, that may be the problem. However, there has not been enough quality and consistent evidence to support extensive computer use as a risk factor for carpal tunnel syndrome, although it may cause a different form of hand pain.
There are no proven strategies to prevent carpal tunnel syndrome, but you can minimize stress on your hands and wrists with these methods:
Your doctor may ask you questions and conduct one or more of the following tests to determine whether you have carpal tunnel syndrome:
History of symptoms. Your doctor will review the pattern of your symptoms. For example, because the median nerve doesn't provide sensation to your little finger, symptoms in that finger may indicate a problem other than carpal tunnel syndrome.
Carpal tunnel syndrome symptoms usually occur while holding a phone or a newspaper or gripping a steering wheel. They also tend to occur at night and may wake you during the night, or you may notice the numbness when you wake up in the morning.
Physical examination. Your doctor will conduct a physical examination. He or she will test the feeling in your fingers and the strength of the muscles in your hand.
Bending the wrist, tapping on the nerve or simply pressing on the nerve can trigger symptoms in many people.
Treat carpal tunnel syndrome as early as possible after symptoms start. In the early stages, simple things that you can do for yourself may make the problem go away. For example:
Other treatment options include wrist splinting, medications and surgery. Splinting and other conservative treatments are more likely to help if you've had only mild to moderate symptoms that come and go for less than 10 months. If you have numbness in your hands, you need to see a doctor.
If the condition is diagnosed early, nonsurgical methods may help improve carpal tunnel syndrome, including:
Nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs, such as ibuprofen (Advil, Motrin IB, others), may help relieve pain from carpal tunnel syndrome in the short term.
There isn't evidence, however, that these drugs improve carpal tunnel syndrome.
Corticosteroids. Your doctor may inject your carpal tunnel with a corticosteroid such as cortisone to relieve pain. Sometimes your doctor uses an ultrasound to guide these injections.
Corticosteroids decrease inflammation and swelling, which relieves pressure on the median nerve. Oral corticosteroids aren't considered as effective as corticosteroid injections for treating carpal tunnel syndrome.
If carpal tunnel syndrome is caused by rheumatoid arthritis or another inflammatory arthritis, then treating the arthritis may reduce symptoms of carpal tunnel syndrome. However, this is unproved.
Surgery may be appropriate if your symptoms are severe or don't respond to other treatments.
The goal of carpal tunnel surgery is to relieve pressure by cutting the ligament pressing on the median nerve.
The surgery may be performed with two different techniques:
Endoscopic surgery. Your surgeon uses a telescope-like device with a tiny camera attached to it (endoscope) to see inside your carpal tunnel. Your surgeon cuts the ligament through one or two small incisions in your hand or wrist. Some surgeons may use ultrasound instead of a telescope to guide the tool that cuts the ligament.
Endoscopic surgery may result in less pain than does open surgery in the first few days or weeks after surgery.
Discuss the risks and benefits of each technique with your surgeon before surgery. Surgery risks may include:
During the healing process after the surgery, the ligament tissues gradually grow back together while allowing more room for the nerve. This internal healing process typically takes several months, but the skin heals in a few weeks.
Your doctor generally will encourage you to use your hand after the ligament has healed, gradually working back to normal use of your hand while initially avoiding forceful hand motions or extreme wrist positions.
Soreness or weakness may take from several weeks to a few months to resolve after surgery. If your symptoms were very severe, symptoms may not go away completely after surgery.
Integrate alternative therapies into your treatment plan to help you cope with carpal tunnel syndrome. You may have to experiment to find a treatment that works for you. Always check with your doctor before trying any complementary or alternative treatment.
These steps may provide temporary symptom relief:
If pain, numbness or weakness recurs and persists, see your doctor.
Here's some information to help you get ready for your appointment and what to expect from the doctor.
Your doctor will usually want to know:
If you think you may have carpal tunnel syndrome, there are some simple things you can do before you see a doctor for the first time.
First, try to determine whether any activities seem to make it worse, and change how you do those or avoid them if possible. For example, if driving seems to cause symptoms, try changing the position of your hands on the steering wheel.
Also, although there is some cost involved, there is no harm in trying a wrist splint at night to see if that helps the symptoms.