WHAT IS CARPAL TUNNEL SYNDROME?
The median nerve is a large nerve that travels down the centre of the forearm to the skin of the thumb, the index finger, the long middle finger and half of the third, or ring, finger. It also supplies sensation to the muscles of the base of the thumb. Nerves can be thought of as a type of wiring that connects your hand and your brain sending electrical signaling back and forth.
To enter the hand the median nerve must pass through the narrow opening across the palm side of your wrist. This opening is made up of a half circle of your wrist bones (called the Carpal bones) and a strong ligament that runs across the wrist. The result is a tunnel – called the carpal tunnel. It is in this tight tunnel that problems can occur because if there is anything that takes up extra space in there, it will cause the nerve to be pressed up tightly against the ligament and get squeezed. There are different things that pass through this tunnel along with the nerve including several tendons. The nerve is most sensitive because it is already lying along the top of the tunnel that is most prone to damage from any type of pressure.
If any nerve in the body is bumped, squeezed, or has sustained pressure applied to it, this can cause sensory changes such as tingling or numbness. For example, bumping the 'funny bone' at the elbow can cause tingling or numbness in the fingers. Nerves also send messages to muscles telling them when to contract so squeezing or damaging a nerve can also cause "motor" problems such as muscle weakness as the nerves ability to talk to the muscle is lost. For example, if a person sits in an uncomfortable position for a long period of time this can put pressure on the nerves in the legs, causing them to 'go to sleep' and feel temporarily paralyzed. This same phenomenon occurs with carpal tunnel syndrome, except that with carpal tunnel syndrome the pressure is often more constant and ongoing and the resulting symptoms more sustained.
HOW COMMON IS CARPAL TUNNEL SYNDROME?
Carpal tunnel syndrome can occur in people of any age, but it most often occurs in people 50 or older. The condition occurs more commonly in women than in men. Younger people, usually men between the ages of 20 and 40, sometimes develop carpal tunnel syndrome as a result of stressful activity that involves heavy use of the wrist or sustained gripping tasks.
What are the warning signs of carpal tunnel syndrome?
Carpal tunnel syndrome can come on suddenly, but more often begins gradually. It may affect one or both hands. If you have carpal tunnel syndrome your earliest symptoms will probably be pain, tingling or numbness in the thumb or the fingers, with the exception of the little and ring fingers. Usually only the inner side of the third finger is affected.
Your fingers may feel 'full' or swollen, and you could have pain that extends from your hand up your arm, possibly all the way to the elbow. These symptoms will probably feel worse at night, particularly when your hand is warm. Many people with carpal tunnel syndrome feel relief of their symptoms when they remove the affected hand from underneath sheets and blankets in order to cool it. Other people find themselves shaking their hands during the night to make them feel better.
You might also notice weakness in your hand, particularly when doing activities that require involvement of the thumb, such as pinching or grasping. This can result in you dropping things more than usual.
The muscles at the base of your thumb (the fleshy part of your thumb on the thumb side of your palm), may become smaller than those on the other hand or than they used to be, or look "flatter" to you. This 'wasting' of muscles usually only occurs after the earlier symptoms of numbness and tingling have been present for some time and likely you have spoken to your doctor before now. If not, make sure you speak to your doctor or go back again if you have this wasting.
WHAT CAUSES CARPAL TUNNEL SYNDROME?
In many cases the cause of carpal tunnel syndrome is not known and it can seem to appear for no reason. However, there are certain conditions that increase the risk of carpal tunnel syndrome – basically those conditions where the size of that tunnel is smaller, or the tissues inside it are larger and swollen. For example, an injury to the wrist that results in damage to the bone can cause carpal tunnel syndrome. This might include a fractured wrist as one example where the healing or healed bone is occupying more space than usual. Various forms of arthritis that result in inflammation of the lining of the wrist joint also cause pressure on the median nerve because of the inflammation of the joints in the wrist or the soft tissues.
Hobbies and occupations that require heavy use of the hand and wrist can also play a role in carpal tunnel syndrome, particularly if the use involves repetitive movements. People who work as construction workers or carpenters; fish, meat and poultry processors; hairdressers; needle workers or knitters; typists or computer operators can be more at risk of getting carpal tunnel syndrome.
Diabetes may also play a role in the development of carpal tunnel syndrome, as may hormonal changes. Some women develop swelling in the hands and feet when pregnant but feel much better ones they have the baby. Others experience symptoms after giving birth or during menopause.
Usually it is a situation where there is not enough room in that canal, and the nerve is being squeezed against the underside of that carpal ligament.
WHAT CAN YOU DO ABOUT CARPAL TUNNEL SYNDROME?
The goal of treating carpal tunnel syndrome is to relieve pain, restore normal sensation and prevent the problem from becoming worse. Establishing the correct diagnosis is important because something can be done to manage most forms of arthritis and most therapies work best when started early in the disease.
If your doctor thinks you have carpal tunnel syndrome he or she will perform a physical examination of the area and may do specific tests.
One test that might be done is called Tinel's test. This involves tapping gently on the front of the wrist, which may cause tingling or pain in the hand. Another test is called Phalen's test. In this test, your wrist will be bent fully forward and then held in that position for a period of time. This may produce tingling or numbness in the fingers.
When the diagnosis is unclear and the problem has persisted despite other attempts to diagnose it, an electrical nerve conduction test can be useful. This test usually requires going to a special clinic. An electrical stimulation is sent down the nerve from various points in the upper arm and forearm. The time it takes for that electrical message to reach a point in the hand is carefully measured. It may show that while the nerve in the upper arm and forearm are carrying the message normally, when the message gets to the wrist it is slowed down or reduced in intensity.
X-Rays may also be taken, but if you have carpal tunnel syndrome the x-rays will probably be normal unless there is an obvious change in the bones due to earlier fractures or damage from arthritis. Blood tests also usually come back normal unless they indicate another condition such as rheumatoid arthritis that could be contributing to the problem.
Once the diagnosis is confirmed various treatments can help decrease your pain and stiffness and increase sensation in your hand. Your active involvement in developing your prescribed treatment plan is essential.
You may find general information in Arthritis Medications: A Consumer's Guide [PDF] even if your disease is not specifically addressed.
NSAIDs reduce pain when taken at a low dose, and relieve inflammation when taken at a higher dose.
For severe pain and inflammation, doctors can inject a powerful anti-inflammatory drug, called a corticosteroid, directly into the affected area. Corticosteroids are man-made drugs that closely resemble cortisone. Cortisone is a steroid that reduces inflammation and swelling. It is a hormone naturally produced by the body. An injection of corticosteroids can provide almost immediate relief for a tender, swollen and inflamed joint. However, this treatment can only be used rarely, since corticosteroids can weaken cartilage and remove the minerals from (and therefore weaken) the bone, resulting in further joint weakness.
GIVING THAT TUNNEL SOME SPACE
If the main problem is that there is just not enough space in that canal for the nerve and all those tendons, lets put the wrist in a position where you can maximize the space available. One common treatment for carpal tunnel syndrome is a resting splint. Often this only needs to be worn at night because we spend nights with our wrists all curled up and that makes things worse! By allowing the tissues the most space possible during the night, you can see if that is enough to relieve the daytime symptoms. Talk to your therapist about this splint.
Be aware that when you do a lot with your wrist in a splint, like trying to do your job, you will be putting more strain on other joints like your elbow and shoulder to get the job done. Talk to your therapists about when you should wear the splint, and what the best routine for you is.
PROTECT YOUR JOINTS
Protecting your joints means using them in ways that avoid excess stress. Benefits include less pain and greater ease in doing tasks. Three main techniques to protect your joints are pacing, positioning your joints wisely and using helpful devices.
Pacing, by alternating heavy or repeated tasks with easier tasks or breaks, reduces the stress on painful joints and allows weakened muscles to rest.
If you are doing an activity that could have a role in causing carpal tunnel syndrome, it is important to stop this activity or change how you do it. For example, a wood carver might use a hammer to hit a chisel rather than hitting it with a bare hand. A person who spends long hours knitting may have to take short breaks at regular intervals.
Positioning joints wisely helps you use them in ways that avoid extra stress. Use larger, stronger joints to carry loads. For example, use a shoulder bag instead of a hand-held one. Also, avoid keeping the same position for a long period of time.
Using helpful devices, such as luggage carts, grocery carts and reaching aids, can help make daily tasks easier. Small appliances such as microwaves, food processors and bread makers can be useful in the kitchen.
When other treatment has not been successful and your symptoms persist, you and your doctor may decide to have surgery done on your wrist. This procedure, called carpal tunnel release, relieves the pressure on the median nerve.
Carpal tunnel release surgery is usually done as outpatient day surgery. It may take several weeks for full recovery, and it will probably be necessary for you to restrict wrist activity for a week or two to assist in full healing. Those people who have jobs that require heavy manual labour may require several weeks away from work. Results of the surgery will depend in part on how long the loss of sensation and muscle wasting has been present.