Chances are you know someone who has had carpal tunnel syndrome or you’ve had it yourself. CTS, which is characterized by tingling, numbness and pain in the hand, fingers, wrist and occasionally the forearm and arm, occurs when the tissues lining the carpal tunnel — a narrow, rigid passageway of ligaments and bones at the base of the hand — become irritated and swollen, compressing and “entrapping” the median nerve, which runs from the forearm into the palm of the hand and provides feeling to parts of the thumb and fingers, excluding the little finger.
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CTS is often caused by a combination of factors, including repeated flexing and other movements of the wrist and fingers, sprains or fractures, continued use of vibrating hand tools and fluid retention during pregnancy or menopause. People with diabetes, an underactive thyroid gland or other disorders that directly affect the nerves are more prone to developing CTS.
Individuals with the autoimmune disease rheumatoid arthritis may be especially prone to CTS. One of RA’s hallmarks is inflammation and swelling of the synovium — the lining of the joints — and according to the website rheumatoidarthritis.net, RA commonly afflicts the wrist joints.
“CTS is the most common compression nerve disorder and is estimated to affect 4 to 10 million Americans,” says Dr. Minna Kohler, the director of the Rheumatology Musculoskeletal Ultrasound Program at Massachusetts General Hospital in Boston. “CTS is common in patients with RA since pain and swelling due to arthritis affecting the hand and wrist can contribute to compression and swelling of the median nerve,” says Kohler, who is also an instructor in medicine at Harvard Medical School. “While repetitive activities can contribute to symptoms of CTS, it can occur in the absence of repetitive use in patients with RA,” she adds.
CTS is not just the most common compression nerve disorder of the upper extremities; it is also the most expensive. The yearly medical costs in the U.S. exceed $2 billion, most of which is from corrective surgery. The non-medical costs are estimated to be much higher and include lost work time, which averages 27 days, longer than any other work-related disorder except fractures. Moreover, 18 percent of people who develop CTS report leaving their job within 18 months.
Three times as many women as men have CTS, which is the same ratio as people with RA, possibly because the carpal tunnel may be smaller in women than in men.
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In the past, it was thought that people with RA had a higher prevalence of CTS than the general population, but a 2015 study published in the International Journal of Rheumatic Diseases found that the incidence is roughly equivalent in both groups. This finding may be the result of the medications used to treat RA.
Dr. Ronald Rapoport, a rheumatologist in Fall River, Massachusetts, agrees, with a caveat. “I don’t think I’d be so bold as to say that [these medications] have reduced the incidence [of CTS] to that of the general population, but they certainly have reduced the incidence, at least in my clinical practice,” says Rapoport, who is chief of the Division of Rheumatology for Southcoast Health.
“The majority of my patients who have RA do not have carpal tunnel syndrome,” he says. “It seems that those [RA patients] who are at greatest risk are those who have a job requiring prolonged use of their hands to do such things as use a computer, a sewing machine or other activities where there is repeated hand use,” he adds.
“Modern RA medications have reduced the incidence of CTS caused by RA or other inflammatory arthritis [because they] treat the underlying swelling and inflammation of arthritis, which reduces compression or irritation of the median nerve,” Kohler confirms.
According to the American Academy of Orthopaedic Surgeons, in most patients, CTS gets worse with time, so it’s important to diagnose and treat the disorder before it progresses too far. Continued pressure on the median nerve can lead to worsening symptoms and nerve damage.
“The majority of time the diagnosis can be made clinically, based on symptoms,” Rapoport says,
“On exam, there may be decreased sensation of the hand when pricked or touched lightly, and tapping the wrist along the nerve may produce an electrical sensation,” Kohler explains.
“At times nerve conduction studies and electromyography can be helpful to confirm the diagnosis, especially in stubborn cases,” Rapoport adds.
Ultrasound can also be used, says Kohler. “[It can] show a swollen, enlarged nerve, as well as swelling or abnormalities of the carpal tunnel, joint or tendon related to arthritis,” she says.
Once CTS is diagnosed, treatment is essential to prevent nerve damage, which can become permanent.
“In RA patients, CTS is treated by treating the underlying arthritis causing swelling and inflammation,” Kohler says. This includes the trifecta of disease-modifying anti-rheumatic drugs, biologics and corticosteroids that are typically used to quell the overactive immune response in RA.
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Local therapy can also be helpful.
“Wrist splints at night, nonsteroidal anti-inflammatory medications and steroid injections to target the carpal tunnel and median nerve can also be used to reduce nerve swelling and treat symptoms,” she says.
When symptoms do not resolve with conservative measures, surgery to relieve — or decompress — the pressure on the median nerve may be necessary.
In general, however, CTS treatment in people with RA is “very successful,” Kohler says. “Often, symptoms completely resolve with treatment of RA.”
“The outlook for people with RA and CTS is much better now [than it was], with the availability of modern RA medications to successfully treat symptoms and improve overall function,” Kohler says.
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People With Rheumatoid Arthritis Face the Risk of Carpal Tunnel Syndrome originally appeared on usnews.com
