Magazine article Occupational Hazards

Is It Carpal Tunnel Syndrome?

Magazine article Occupational Hazards

Is It Carpal Tunnel Syndrome?

Article excerpt

It looks like carpal tunnel syndrome, it feels like carpal tunnel syndrome...but is it? Here's what you should know about this malady.

Within the past decade, the number of carpal tunnel syndrome (CTS) cases apparently has declined, but that decline may be less a product of improved ergonomics and working smarter than it is the gift of improved diagnostic criteria and techniques. Thus, while CTS is not epidemic, it's still a hazard for your best employees.

The carpal tunnel is a slender conduit in the base of the palm through which the flexor tendons of the fingers and thumb and the median nerve pass. The tunnel is defined by the carpal bones of the wrist and the transverse carpal ligament. The median nerve, which extends from the fingertips to the neck, delivers power to the thumb muscles and sensation to the thumb, index, middle and part of the ring fingers. When tissues within the carpal tunnel are inflamed or swell, the median nerve is compressed, producing searing pain in the wrist, particularly at night, numbness and tingling in the fingers, and the inability to grasp objects.

Margit L. Bleecker, M.D., director of the Center for Occupational and Environmental Neurology, Baltimore, notes that symptoms similar to CTS can arise if function in the median nerve is impaired or subjected to compression at its origin in the neck. According to Stephen A. Dawkins, M.D., MPH, BS, FACOEM, medical director, Hospital Occupational Medicine, Atlanta, misdiagnoses of CTS were common as recently as five years ago, but patients and doctors have become better educated about CTS, even as diagnostic tools have become more sophisticated.

Making the Diagnosis

Diagnosing CTS begins with taking a medical history of the patient and performing a physical examination. The medical history identifies predisposing factors, such as diabetes, tendinitis, fluid retention, wrist fracture, rheumatoid arthritis, hypothyroidism, tumors, pregnancy and obesity.

"In the physical exam, we look not only at the median nerve, but at the other muscles, tendons and nerves in the upper extremity, beginning at the neck and working down to the fingertips," says Bleecker.

Nerve conduction and electromylegraphic studies are performed to detect abnormalities in the median nerve. X-rays can help rule out arthritis and identify old fractures. The doctor may tap the skin over the median nerve to produce tingling in the fingers - Tinel's Sign - or may perform Phalen's test, in which the patient places his arms with elbows flexed on the table, allowing his wrists to fall forward freely. Tingling in the fingers appears within one minute in patients with CTS. Bleecker also uses video analysis of the patient at work and biofeedback, in which electrodes attached over the patient's muscles alert him to risky postures.

Despite the precision of these diagnostic tools, "The physical exam is probably one of the weakest [diagnostic tools] we have," Bleecker observes. "That's why the history so important."

"We try to answer the question of the source. That involves getting the history of when these symptoms occur, what makes them worse or better, and where they are located," she explains. "In an occupational setting, for example, when there is a constant jacking up of workload, people do not have time to adjust. If you increase the speed of an assembly line, you can bring on the symptoms; slow it down and you'll see the symptoms go away." Bleecker opposes the four-day, 10-hour-per-day work week for the same reason.

Further, says Bleecker, "Gender clearly is an issue. Contrary to old literature, which identifies the ratio of women to men who suffer from CTS at 10 to 1, my experience puts it at 2 to 1. It depends upon the nature of the job."

Dawkins divides risk factors into occupational, medical and hobby categories and asks the patient questions about each. When risk factors are identified, the next step is to discern the percentage of the day spent in those activities and to determine how medical conditions are being controlled. …

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