Carpal tunnel syndrome – what is it?
Carpal tunnel syndrome is a condition brought on by a pinched nerve at the wrist. There is a space in the wrist called the carpal tunnel. The median nerve and nine tendons pass from the forearm into the hand, through this tunnel, which is “roofed” by the transverse carpal ligament (see image above). Carpal tunnel syndrome occurs when pressure builds up and causes swelling in this tunnel. This puts pressure on the median nerve which is very sensitive. When the pressure from the swelling becomes great enough to change the way the nerve works, then numbness, tingling, and pain may be felt in the hand and fingers.

What are causes of carpal tunnel syndrome?
A common cause of the pressure buildup in the tunnel is swelling of the lining of the tendon, which is known as tenosynovitis. Repetitive use of the hands can cause a pressure buildup in the tunnel. Bone dislocations, fractures, and arthritis can also narrow the tunnel, but are not as common. Fluid retention during pregnancy can sometimes cause swelling of the tunnel and symptoms of carpal tunnel syndrome, which often go away after delivery. The medical conditions of hypothyroidism, rheumatoid arthritis, and diabetes mellitus are other fairly common causes.

What are signs and symptoms?
Patients complain of pain, numbness, tingling, or a combination of these three symptoms in either one or both hands. The most common distribution of the numbness or tingling is in the thumb, index, middle, and ring finger. The little finger (pinky) is rarely affected. The symptoms are typically felt at night or upon awakening. Patients may say they need to “shake their hands” to bring “circulation” back into the hands. Symptoms may also be noticed during daily activities such as driving (clutching the steering wheel) or reading a newspaper. Patients may notice that they have a weaker grip or may drop things. In severe cases, muscles at the base of the thumb waste away (thenar atrophy), or the patient may have constant numbness. This is a more serious situation which must be addressed immediately in order to avoid a permanent loss of strength or sensation.

How is carpal tunnel syndrome diagnosed?
The most important tool for diagnosis is a complete history and physical examination. It is very important to obtain a detailed history on exactly how the hands have been used, as well as any prior injuries and symptoms. Occasionally x-ray can be performed to check for other causes of the symptoms such as arthritis or an underlying fracture. The hallmark of diagnosis is a nerve conduction study (NCV) and electromyogram (EMG). This test will both confirm the presence of carpal tunnel syndrome, assess how severe the condition is, and assure that there is no other compression of the median nerve at a place other than the wrist, such as the forearm, shoulder, or in the neck. A pinched nerve in the neck or other places mentioned can “masquerade” as carpal tunnel syndrome. Depending upon the patient, laboratory tests may be done if a medical condition is suspected as a underlying cause of the patient’s symptoms.

How is carpal tunnel syndrome treated?
It is often possible to eliminate the symptoms of mild to moderate carpal tunnel syndrome without surgery. Treatments include occupational therapy, medication and injections, as well as a possible role for nutritional intervention.

What is the role of occupational therapy?
Occupational therapists can help the patient in several ways. The therapist can help the patient to change the way they do activities in order to reduce repetitive or strenuous use of the hand, by teaching proper ergonomics. Performing activities while keeping the wrist in a straight position may help reduce the swelling within the tunnel, thereby allowing more room for the nerve. Prefabricated wrist splints can help maitain proper position. Occupational therapists occasionally fabricate customized splints which would be worn during the night primarily. These may relieve symptoms that interfere with sleep. In more severe cases, these may be worn during the day as well. Therapists can also utilize other treatment strategies (ultrasound, joint mobilization, tendon gliding exercises, development of a home exercise program) in an effort to decrease pressure within the carpal tunnel, thereby relieving symptoms and signs of the disease.