Carpal Tunnel Syndrome is a condition that causes pain, tingling, or numbness in the wrist, hand, or fingers. It may develop when the nerve that provides sensation to the fingers doesn’t have enough room when it passes through a space within the wrist known as the carpal tunnel. If this nerve – the median nerve – becomes compressed, the pressure causes unpleasant symptoms.

The median nerve may become constricted within the carpal tunnel for several reasons. Common causes[1] of Carpal Tunnel Syndrome include:

  • Rheumatoid arthritis
  • Gout
  • Diabetes
  • Hypothyroidism, or underactive thyroid
  • Wrist injuries
  • Pregnancy
  • Menopause
  • Certain chemotherapy medications

What factors lead to increased pressure or inflammation?

Compression of the median nerve may cause symptoms like pain, tingling, or numbness in the affected fingers, hand, or wrist. The space within the carpal tunnel may become limited in different ways, putting pressure on the nerve.

For example, inflammation[2] may cause other structures within the carpal tunnel to crowd out the median nerve.

“Multiple conditions can result in enlargement of the flexor tendons within the carpal tunnel, [including] inflammatory diseases such as gout and rheumatoid arthritis,” says Nathan Lesley, MD, an orthopedic surgeon who specializes in hand and upper extremity surgery, the founder and CEO of the Hand to Shoulder Center in Fort Worth, Texas.

Performing repetitive motions with the hands or wrists may also lead to inflammation. This is why some people may associate certain jobs with a higher incidence of carpal tunnel syndrome, including people whose power tools are at work or those who type or play musical instruments for hours at a time.

Additionally, fluid may build up within the wrist, limiting the space available for the median nerve.

“Fluid retention – which occurs during pregnancy, for example – is a common cause of Carpal Tunnel Syndrome,” Lesley says.

Rheumatoid arthritis causing carpal tunnel

One possible complication of rheumatoid arthritis is Carpal Tunnel Syndrome. The condition is more common among people with rheumatoid arthritis than among people without the condition [3]. Rheumatoid arthritis causes the joints to swell. The median nerve may become compressed within the narrow carpal tunnel if the wrists are affected.

“The carpal tunnel is a closed space in which the median nerve and nine tendons reside,” Lesley says. “When these nine tendons become enlarged, the pressure builds within the carpal tunnel, thereby compressing the median nerve. In order to relieve the pressure and allow the nerve to function properly, the carpal tunnel needs to be opened.”

Wrist injury-causing carpal tunnel

When you injure yourself, the affected tissue becomes inflamed. Certain wrist injuries may cause inflammation to the tissue which lines the tendons within the carpal tunnel and may contribute to carpal tunnel syndrome. This is more likely to happen if the injury takes a long time to heal.

“Immediately following a severe contusion, sprain, or a fractured bone, swelling of the tissues can cause compression of the median nerve, resulting in what is known as acute Carpal Tunnel Syndrome,” Lesley says. “This can also occur as a result of a deep infection within the wrist.”

People who don’t receive medical treatment for wrist injuries may also increase their risk of developing Carpal Tunnel Syndrome. As Dr. Lesley says, “An incorrectly healed fracture can result in Carpal tunnel syndrome. This occurs when a bone – typically the radius [in the forearm] –heals in an angulated position, resulting in a change in shape and size of the carpal tunnel.”

A surgical procedure may help to relieve carpal tunnel pain after a wrist injury[4].

Learn more about the SmartRelease endoscopic carpal tunnel release procedure.