A band of fibrous tissue surrounds the wrist to support it. The tight space between this fibrous band and the wrist bones called carpels is called the carpal tunnel. A nerve called median nerve passes through this tunnel. Many conditions can compress this nerve inside this tunnel causing tingling and numbness of the thumb, index, and the middle fingers, This condition is known as Carpel Tunnel Syndrome.
Common conditions that can lead to carpel tunnel syndrome are Obesity, Hyperthyroidism, many types of Arthritis, Diabetes and trauma to the wrist. Tendon injury caused by repetitive work, such as uninterrupted typing, can also cause carpal tunnel syndrome. Some rare diseases like amyloidosis, sarcoidosis, multiple myeloma and leukemia can cause this syndrome by causing deposition of abnormal substance in the carpal tunnel and by causing the compression of the median nerve.
Nerve compression initially causes numbness and tingling of the hand in the distribution of the median nerve (the thumb, index, middle, and part of the fourth fingers) predominantly at night and can awaken people from sleep. Worsening of symptoms at night may be attributed to flexed-wrist sleeping position and fluid accumulating around the wrist and hand. These symptoms may be temporary or may persist and progress.
Progression of the disease may later cause a burning sensation, and/or cramping and weakness of the hand. Reduced grip strength may lead to frequent dropping of objects from the hand. Sometimes, sharp shooting pains may occur in the forearm. In later stage wasting muscles may develop, particularly those near the base of the thumb. Tapping the front of the wrist may reproduce tingling of the hand, and is referred to as Tinel’s sign. Similarly, symptoms can be reproduced by bending the wrist forward, it is to as Phalen’s maneuver.
In carpel tunnel syndrome, nerve conduction velocity test is abnormal. It means, the nerve impulse slows as it crosses through the carpal tunnel. Certain blood tests are done to find out, which medical condition is responsible for the syndrome, these are thyroid functions, complete blood counts, blood sugar and protein analysis. X-ray and MRI tests of the wrist and hand might further be helpful in diagnosis.
Initial treatment includes rest, splinting the wrist and occasionally ice application. Modification of the occupational activities such as adjustment of co mputer keyboards and chair height. These measures, as well as periodic resting can prevent the symptoms which are caused by repetitive overuse. Specific diseases are treated individually. Fractures will require orthopedic measures. Obese individuals must reduce their weight. Rheumatoid diseases will require aggressive treatment. Wrist swelling that can be associated with pregnancy resolves in time after delivery of the baby. Vitamin B6 (pyridoxine) can help to relieve symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs) can help in decreasing inflammation and reducing pain. Corticosteroids are injected directly into the involved wrist joint for rapid relief of persistent symptoms.
Most patients do well with conservative measures and medications. However, chronic pressure on the median nerve can result in the permanent nerve and muscle damage and surgery procedure called carpel tunnel releases is considered in such a scenario to reduce the nerve pressure by cutting the band of tissue around the wrist. After carpal tunnel release, patients often undergo exercise rehabilitation. Though it is uncommon, symptoms can recur.