Practice skepticism with carpal tunnel diagnoses
Other medical conditions often the culprit
Carpal tunnel syndrome (CTS) is grossly overdiagnosed as an occupational injury, according to a researcher who says most CTS cases can be traced to diseases having nothing to do with repetitive motion in the workplace.
Occupational health professionals should take the time to look for other, nonwork related causes of CTS before jumping to a diagnosis, warns Steven Atcheson, MD, a rheumatologist with Arthritis Specialists of Northern Nevada in Reno. He tells Occupational Health Management that he sees many patients who have been diagnosed as having occupational injuries when, in fact, their CTS can be attributed to obesity or diseases such as diabetes, hypothyroidism, gout, or rheumatoid arthritis.
CTS has become almost an automatic diagnosis for the wrist and hand symptoms commonly associated with the problem, Atcheson says. That is the result of the exploding interest in CTS over the past years that has decreased clinicians' doubts and suspicions, he says.
"The index of suspicion in many of these cases was virtually zero," Atcheson says. "We saw the explosion in CTS diagnoses start in 1985 when OSHA declared that repetitive strain could cause these problems. But when I was in school in the '60s and '70s, we were taught that carpal tunnel syndrome had a medical cause and you looked for those causes."
Need to look for other diagnoses
Atcheson recently studied the underlying causes of CTS symptoms by taking a close look at 297 patients who had been diagnosed with work-related upper extremity disorders.1 He found that a third of all those patients had atraumatic illnesses that were capable of causing arm pain or other CTS symptoms. Most of those diagnoses (68%) would have been missed by looking only at patient histories and record reviews, he says.
Two-thirds of the patients (198) had been diagnosed with CTS 420 times in more than 1,000 office visits, yet diagnostic laboratory tests had been ordered only 25 times. That is much of the problem, Atcheson explains.
Specialists may be required
"Some of these conditions were diagnosable only by a rheumatologist or someone else particularly interested in some of these conditions," he says. "These are fairly subtle things to diagnose if you don't do it on a daily basis. I'm not at all sure a typical occupational health provider could make that diagnosis without ordering the right tests."
Overall, 40% of the patients defined as having CTS were found to have a metabolic, inflammatory, or degenerative condition that could cause the symptoms. Only 12% of the patients already knew they had those conditions, so asking about the patient's history is often insufficient.
Never assume CTS symptoms are attributable to workplace conditions, even if the person is employed in data entry, Atcheson advises.
"You should assume off the bat that there are medical conditions that might cause the CTS," he tells OHM. "Even if it's not true, just pretend that they might have arthritis or an inflammatory or metabolic condition that might cause those symptoms and then rule them out."
He also says such patients always should have an X-ray of the hands and wrists together. The X-ray could reveal arthritis as the underlying cause of the CTS symptoms, for instance, and the arthritis finding would affect the treatment decisions.
Reference
1. Atcheson SG, Ward JR, Lowe W. Concurrent medical disease in work-related carpal tunnel syndrome. Arch Intern Med 1998; 158:1,506-1,512.
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