Causes of carpal tunnel syndrome vary, but they all involve compression of the median nerve in the wrist’s carpal tunnel cavity. This causes numbness or tingling sensations in the hand, usually in the index finger, middle finger, and thumb, later accompanied by decreased grip strength and overall weakness in the hand. Preexisting illnesses or other conditions, general anatomy, and stress or injury are the most common causes of carpal tunnel.
Since the syndrome is induced by nerve compression, any health conditions that create swelling in the wrist could potentially be one of the causes of carpal tunnel. The water retention that often accompanies pregnancy and menopause is one cause, as it creates swelling in the joints that could press against the nerve. Diabetes can also cause carpal tunnel because it affects fluid retention and swelling in the body. Additionally, hormonal conditions, such as hypothyroidism and obesity, are sometimes causes of carpal tunnel syndrome. As a result of obesity, the extra fat stored can begin to put pressure on the body’s organs and nerves.
In addition to these conditions, illnesses such as leukemia, sarcoidosis, and amyloidosis can also lead to carpal tunnel syndrome because they introduce abnormal material into the wrist, which is viewed as foreign by the body. These added substances initiate an inflammatory response in the area, irritating and compressing the nerve. Cancers or even benign tumors in the wrist area can also press down on the nerve and increase the likelihood of carpal tunnel.
General anatomy and body structure can also contribute to the development of carpal tunnel syndrome. Some individuals simply have a smaller carpal tunnel. If the carpal tunnel is small, then the risk of inadvertently compressing the nerve is much greater.
Stresses placed on the median nerve from activities such as typing or writing are also common causes of carpal tunnel syndrome. Typing for an extended period of time without proper form, sufficient rest, or wrist support creates an inflammatory response in the wrist. This can cause generalized swelling that presses against the nerve. To avoid injury to the wrist from typing or writing, elevate the wrists and take frequent breaks, especially if the wrist starts to feel sore or stiff.
Direct injuries to the nerve can also cause carpal tunnel. In these cases, the onset is much more sudden. Damage or injury to the tendons in the wrist through overly strenuous flexing or extending can create swelling, leading to nerve compression. The damage is exacerbated when the muscles and tendons are not allowed to rest.
