Carpal tunnel syndrome is caused by pressure on the median nerve, which runs along the length of the arm, passing through a narrow passageway on the wrist called the carpal tunnel.
The condition often starts by causing numbness and tingling in your hands, particularly at night, or noticed on waking in the morning.
Over time the pain of carpal tunnel syndrome can worsen and if left untreated the nerves may suffer permanent damage and you could lose feeling in your hand and some movements of the thumb.