Last updated on 9 February 2021
Carpal tunnel syndrome (CTS) is a condition where the median nerve becomes compressed in the carpal tunnel area of your wrist.
The median nerve runs the length of your arm, goes through the carpal tunnel in your wrist and ends in the hand. This nerve controls the movement and feeling in your thumb and all fingers except your little finger. When the nerve becomes compressed within the carpal tunnel, you will experience a great deal of discomfort that can disrupt your sleep. Massaging and shaking your hand can alleviate symptoms temporarily, but are not long-term solutions. If left untreated, the symptoms can recur.
Symptoms of carpal tunnel syndrome
Symptoms of carpal tunnel syndrome usually start gradually and can occur at any time. They include:
- Tingling or numbness. Sensations of tingling or numbness may be felt in your fingers or hand, usually the thumb and index, middle or ring fingers. This sensation may travel from your wrist up your arm. Over time, the numb feeling may become constant.
- Weakness. The numbness in your hand may lead to weakness, causing you to drop objects.
- Difficulty with small tasks, such as handling small objects, grasping the steering wheel, holding a book to read, writing, and using a computer keyboard.
Causes of carpal tunnel syndrome
For most cases of CTS, the cause of the condition is unknown. However, you are more susceptible to it as you get older, if you are female, and if you have existing medical conditions such as diabetes mellitus, hypothyroidism, rheumatoid arthritis and gout. Performing repetitive motions such as typing, or any movement of the wrist, especially when your hands are lower than your wrist, can increase your risk of CTS.
Carpal tunnel syndrome is more common in people with diabetes. The relationship between the two is complicated, but research suggests that the link between diabetes and carpal tunnel syndrome could be due to excessively high blood sugar levels, which results in carpal tunnel tendons becoming glycosylated (sugar attaching to the tendon proteins and restricting their ability to move freely).
Hypothroidism is a condition in which the thyroid gland doesn’t produce enough thyroid hormone. Severe, long-term, untreated hypothyroidism may cause carpal tunnel syndrome, where there is soft tissue swelling that presses on the wrist nerve.
Rheumatoid arthritis is a long-term condition that causes pain, swelling and stiffness in the joint. Carpal tunnel syndrome is a common complication in people with rheumatoid arthritis. It is caused by compression of the nerve that controls sensation and movement in the hands.
Gout occurs when the body produces too much uric acid, a waste product. The uric acid forms crystals in the joints, instead of being excreted in the urine. The inflammation from the disease causes swelling within the carpal tunnel, which compresses the nerve, resulting in carpal tunnel syndrome.
Risk factors for carpal tunnel syndrome
- Abnormally small bones that form the carpal tunnel. This puts pressure on the median nerve.
- Frequent and repetitive movements of the hands and wrists may create harmful pressure on the median nerve or worsen existing nerve damage.
- Pregnancy may result in fluid retention that may increase the pressure within the carpal tunnel, irritating the median nerve.
- Women are more likely to develop carpal tunnel syndrome than men. Additionally, being in menopause and having had a mastectomy also increase the risk of developing the condition owing to hormone changes that occur.
- Obesity. A body mass index of 3 or more increases the risk of carpal tunnel syndrome although the reason why is not clear.
- Medical conditions that are nerve-damaging or inflammatory, including rheumatoid arthritis, diabetes, hypothyroidism or lupus.
When to seek medical attention?
CTS is a severe condition that requires early medical intervention for the best treatment outcomes. When diagnosed and treated early, the symptoms of carpal tunnel syndrome can often be relieved without surgery. If left untreated, the thenar muscles, 3 short muscles located at the base of the thumb which control the movements of the thumb, become weakened and wasted. This results in irreversible functional disability of the hand. Simple tasks such as buttoning your shirt or blouse, using a pair of chopsticks and picking up small objects can become a great challenge. Therefore, it is important that CTS is diagnosed and treated as early as possible.
How is carpal tunnel syndrome (CTS) diagnosed?
If you experience symptoms such as pain, numbness and tingling in the thumb, index finger, middle finger and the thumb side of your ring finger, consult your doctor for a diagnosis. You will likely be referred to a specialist hand surgeon for a more accurate diagnosis. Your surgeon will first ask for your full medical history before conducting a clinical examination of your hands.
Medical history of symptoms
Your doctor will review the pattern of your symptoms to rule out other conditions other than carpal tunnel syndrome.
A physical examination includes testing 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.
An X-ray of the affected wrist may be helpful to exclude other causes of wrist pain, such as arthritis or a fracture.
Nerve conduction study
Two electrodes are taped to your skin and a small current is passed through the median nerve to see if electrical impulses are slowed in the carpal tunnel.
A thin-needle electrode is inserted into specific muscles to evaluate the electrical activity when muscles contract and rest. This can identify damage to the muscles controlled by the median nerve.
One or more diagnostic tests may be arranged to evaluate the function of the median nerve and to understand the location and severity of the compression of this nerve. These include:
This is a simple test where your doctor will tap over your median nerve at the wrist, to see if it produces a tingling sensation in your fingers.
Also known as a wrist flexion test, you will be asked to rest your elbows on a table while allowing your wrists to fall forward freely. If you have CTS, your fingers will feel numb and tingly within 60 seconds. If the symptoms appear quickly, this indicate the CTS is severe.
Your doctor may recommend an X-ray to determine if your limited wrist motion or range of movement may be caused by an injury or degenerative disease like arthritis.
Nerve conduction studies and/or electromyography (EMG)
In nerve conduction studies, a small, short electrical current is administered to help measure how well the median nerve is able to transmit electrical impulses to the nearby muscles. If necessary, your doctor will also recommend a needle electrode examination, in which a fine needle is inserted to examine electrical activity in the muscles. There is nothing injected or extracted during this procedure. Nerve conduction studies together with needle electrode examination is known is electromyography.
Why see a hand surgeon?
Hand surgeons are trained to diagnose and have vast experience in treating all problems related to all hand conditions such as the hand, wrist and forearm exclusively. They are also well equipped with skills and knowledge to handle neglected cases of CTS as well as recurring cases where surgery had been unsuccessful previously.
Treatment options for carpal tunnel syndrome (CTS)
If you have mild symptoms of CTS, your hand surgeon will advise you to make modest changes to your lifestyle, to prevent it from getting worse.
These may include things like easing your grip while holding tools or appliances or using less force during daily tasks such as typing or washing. It may also help to avoid doing repetitive movements for long periods, so try switching hands or alternating between different activities.
If your work requires prolonged or intensive use of your hands or hand-held appliances that vibrate or require force, taking hourly breaks can help. During these breaks, you can perform simple exercises such as making a fist then releasing the tension in your fingers by spreading them out as far as you can.
Your hand surgeon may prescribe oral anti-inflammatory medication such as corticosteroids to help reduce the swelling and relieve pain. Corticosteroids can also be administered as an injection.
A wrist splint or brace can help to restrict your wrist movement, allowing some reprieve from normal daily activities. It may also be particularly helpful when worn at night, as it’s common for your wrist to remain bent during your sleep.
Some people may find it helpful to consult a physiotherapist, who can provide advice on exercises to stretch and strengthen the muscles in your hand and wrist. You may also need to learn new ways to perform daily tasks, especially those that are essential or required for work, to ease the pressure on your hand and wrist.
If symptoms persist, you may need surgery. Your hand surgeon will assess your condition and take into account factors such as your age and how long you have been suffering from the symptoms.
If you have had an unsuccessful CTS surgery previously, your hand surgeon may perform microsurgical neurolysis, a procedure that releases tight scar tissue around the median nerve. If necessary, soft tissue is transferred onto the bare median nerve after this is done to prevent scarring and a return of symptoms. A hypothenar fat pad flap transfer is one example of a soft tissue transfer.
Article contributed by Dr Aaron Gan, hand surgeon at Mount Elizabeth Hospital
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