CTS is caused predominantly by compression of the median nerve at the wrist due to hypertrophy or edema of the flexor synovium. Pain is thought to be secondary to nerve ischemia rather than direct physical damage of the nerve. CTS is more prevalent in females. Pain generally is worse at night. CTS is unlikely if no symptoms are present in digits 1,2, or 3.
Symptoms are most often bilateral, insidious in onset, and progressive in nature.
With advanced nerve compression, an aching sensation is persistent and static and may radiate to the forearm and elbow. Activities involving repetitive wrist flexion, such as assembly packing, computer keyboard work, playing a musical instrument, and craftwork, can cause inflammation of the flexor tendon sheath. Trauma of any type, including fractures, can cause edema that can compress the median nerve. Pregnancy or oral contraceptive-related edema can cause compression of the median nerve. The physician who follows the patient after the acute presentation usually orders imaging studies and other tests discussed below.