The old expression "the straw that broke the camel's back" is quite appropriate in regards to many human diseases.
Carpal tunnel syndrome is a disease caused by the compression of the median nerve as it passes through the carpal tunnel in the wrist, though patients can experience carpal tunnel symptoms if there is nerve interference anywhere along the course of the nerve from the neck to the shoulder, down the arm, and to the hand.
When a nerve is slightly pinched, you may not notice it at all. Or you may not start experiencing symptoms until further pressure is placed on the nerve or it becomes compressed at another location along the course of the nerve. For others, there may be pressure on the nerve but symptoms don't begin to show unless they use their wrist repetitively for a period of time.
One study looked at women during both early and late pregnancy. Nerve conduction tests revealed that 11% of the expectant mothers had results in line with carpal tunnel syndrome but did not yet have symptoms. As their pregnancies advanced, the stresses on their bodies increased and many of these patients began exhibiting carpal tunnel symptoms.
While many patients first seek chiropractic care because of symptoms like those associated with carpal tunnel syndrome (or more commonly back and neck pain), the underlying problems may have been in place for some time before a "straw" finally "broke the camel's back" and they began experiencing symptoms uncomfortable enough to motivate them to seek care.