Symptoms and Disease Progression
The early symptoms of CTS typically include tingling or burning in the parts of the hand that receive innervation from the median nerve. These include the palm and the palmar sides of the middle three fingers, as well as the palm side of the wrist. Pain may also radiate up the arm to the shoulder and sometimes the neck, causing stiffness. These symptoms are caused by an increased volume of tissue in the carpal tunnel (Armstrong 1984; Werner 1997).
In many cases, patients complain of waking in the middle of the night with pain and a feeling that the whole hand is asleep. Careful investigation usually shows that the little finger is unaffected because the ulnar nerve rather than the median nerve services that finger.
This can be a key piece of information in making the diagnosis. If you awaken with your hand asleep, pinch your little finger to see if it is numb. Other complaints include numbness or growing weakness while using the hand for gripping activities, such as sweeping and hammering, or during repetitive finger flexion activities, such as typing.
As the condition worsens, daytime paresthesia (a sensation of prickling or tingling of the skin) can become common. The prickling is aggravated by activities such as typing, playing piano, using a computer mouse, driving, holding a book or phone, and combing hair. In long-standing or severe cases of CTS, the muscle group at the base of the thumb might degenerate due to loss of nerve supply, diminishing manual dexterity. This condition may cause difficulty with daily activities such as buttoning clothes and holding small objects. Pain and tingling can also occur in the forearm, elbow, shoulder, and neck. If the condition is allowed to progress, the muscles supplied by the median nerve in the hand may become weak and degenerate. This results in an inability to bring the thumb into opposition with the other fingers, hindering the grasp.
In advanced stages of CTS, the individual nerve cells making up the median nerve can lose their protective layers of myelin. Disruption of the myelin sheath results in impaired conduction of nerve impulses and eventually leads to damage of the axons themselves, producing potentially permanent nerve injury (Werner 2002).