The median nerve passes through a narrow passageway called the carpal tunnel to the hand. If the carpal tunnel becomes narrowed due to, e.g. swelling, a broken wrist, overstraining the hand or tight tissues, the nerve is unable to pass through freely and it may become pinned or trapped.
People with long-term diabetes are 4–6 times as likely to get carpal tunnel syndrome. According to a Finnish study, approximately 20–30 percent of adults with diabetes have been diagnosed with it. The carpal tunnel syndrome is considered to be linked to diabetic nerve damage more than an actual pinned nerve in the carpal tunnel area. However, the underlying factor can also be the connective tissue around the carpal tunnel becoming stiff. Other predisposing factors include obesity, rheumatoid arthritis, kidney disease and underactive thyroid.
A common symptom is a numbness of the hands that wakes up at night and eases up when shaking the wrists. The numbness can also radiate from the wrist up to the upper arm. If the condition becomes worse, the thumb may lose power and the pinch grip of thumb and forefinger becomes weaker. The condition is also called the canalis carpi syndrome.
Usually, carpal tunnel syndrome is suspected on the basis of typical symptoms, risk factors and a doctor’s examination. Normally, the diagnosis is confirmed with electromyographic recording or ENMG test.
You can wear a wrist brace to alleviate the numbness and pain at night. If required, the condition can be corrected with an operation where the carpal tunnel is widened.