Carpal Tunnel Syndrome

A 67-year-old man presented for evaluation of atrophy of the left thenar eminence that had developed within the past 2 weeks. He denied hand weakness. The patient had had symptoms of bilateral carpal tunnel syndrome for more than 12 years. His main symptom was numbness of the fingertips, which made buttoning his shirt and pants pocket difficult. He also had difficulty with fine manipulation, such as picking up paper clips.

Dr Robert P. Blereau, of Morgan City, La, noted that the Tinel sign was strongly positive on the patient’s left hand and less so on his right hand. A nerve conduction study confirmed severe left and moderately severe right carpal tunnel syndrome. Results of the study showed severe prolongation of right median sensory and motor distal latencies, absent left median sensory and motor responses, rare acute denervations with chronic neurogenic changes in the right abductor pollicis brevis, and diffuse denervation with no obvious recruitable units in the left abductor pollicis brevis.

Carpal tunnel syndrome—produced by pressure on the median nerve as it traverses through the carpal tunnel at the wrist flexor—is the most common nerve entrapment syndrome. It often develops in middle age and during pregnancy. Athletes and workers who use prolonged repetitive wrist motions are prone to the condition. Precipitating factors include tenosynovitis of adjacent flexor tendons (from overuse and rheumatoid arthritis), tumors, edema of pregnancy, and hypothyroidism or associated neuritis from diabetes.

Typical symptoms include pain of the hand and fingers that ascends proximally into the forearm and, at times, the shoulder. Patients may have associated paresthesia and numbness in the median nerve distribution of the fingers that excludes the little finger and ulnar side of the ring finger. Symptoms may be increased at night; flexion of the wrist during sleep that causes more pressure on the median nerve may awaken the patient. Thenar muscle atrophy is a late sign.

Mild cases may be treated with night wrist splints, NSAIDs, or oral corticosteroids. Daytime wrist splints and corticosteroid injections into the carpal tunnel may be used in more severe cases. Carpal tunnel syndrome during pregnancy usually resolves following delivery. Operative carpal tunnel release is the last resort for those with atrophy or weakness of the thenar muscles or intolerable symptoms that do not respond to conservative treatment. This patient was referred to an orthopedist for consideration of carpal tunnel release.