Patients with arthritis of the carpometacarpal joint of the thumb will have a positive Watson's test and radiographic evidence of arthritis. Waldman MD, JD, in Pain Review, 2009 Differential DiagnosisĬarpal tunnel syndrome is often misdiagnosed as arthritis of the carpometacarpal joint of the thumb, cervical radiculopathy, or diabetic polyneuropathy. Though using the computer keyboard may aggravate symptoms of CTS, keyboard use does not increase the risk of developing CTS ( Mediouni et al., 2014 Shiri and Falah-Hassani, 2015 Stevens et al., 2001). The highest reported incidence of work-related CTS, based on the number of carpal tunnel surgeries performed, was 15% among a group of meat packers. Increased risk for the syndrome has been found in meat packers, garment workers, butchers, grocery checkers, electronic assembly workers, musicians, dental hygienists, and housekeepers. CTS appears to occur in work settings that include repetitive forceful grasping or pinching, awkward positions of the hand and wrist, direct pressure over the carpal tunnel, and the use of handheld vibrating tools. Symptoms consistent with hand and wrist arthritis in a variety of occupational settings are now recognized as being much more common than CTS ( Dillon et al., 2002). Although a proportion of these cases have bona fide CTS, longitudinal natural history data suggest that the majority of industrial workers do not develop symptoms of CTS ( Nathan et al., 1998). Work-related wrist and hand symptoms (repetitive motion injury) from cumulative trauma in the workplace have received increasing attention by the general public in recent years ( Thomsen et al., 2002).
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A positive Tinel sign, in which percussion of the nerve at the carpal tunnel causes paresthesias in the distribution of the distal distribution of the median nerve, is present in approximately 60% of affected patients but is not as specific for CTS and may be false positive. Phalen maneuver (flexing the patient’s hand at the wrist for 1 minute) or reversed Phalen maneuver (hyperextension of the wrist for 1 minute) often reproduces the symptoms it is present in about 80% of patients, and is rarely false positive ( Padua et al., 2016). Thenar (abductor pollicis brevis muscle) weakness and atrophy may be present in advanced cases of CTS ( Fig.
CARPAL TUNNEL SKIN
Objective sensory changes may be found in the distribution of the median nerve, most often impaired two-point discrimination, pinprick and light touch sensation, or occasionally hyperesthesia, in the thumb, index, and middle fingers, most evident in finger tips, with sparing of the skin over the thenar eminence. Symptoms are often provoked after excessive use of the hand or wrist or during ordinary activities such as driving or holding a phone, book, or newspaper, in which the wrist is assumed in either a flexed or extended posture. Referred pain may radiate to the forearm and even as high as the shoulder ( Stevens et al., 1999). Patients complain of tingling numbness, and burning sensations, which often awaken them from sleep. Symptoms consist of nocturnal pain and paresthesias, most often confined to the thumb, index, and middle fingers, but may be reported to involve the entire hand. The syndrome is frequently bilateral and usually of greater intensity in the dominant hand. Because the transverse carpal ligament is an unyielding fibrous structure forming the roof of the tunnel, tenosynovitis or arthritis in this area often produces pressure on the median nerve.
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This entrapment occurs in the tunnel through which the median nerve and long finger flexor tendons pass. Both the incidence and prevalence of CTS seem to be increasing. CTS prevalence in a primary care population is about 36 per 10,000 people, with an annual incidence of 19 per 10,000 for men and 36 per 10,000 for women ( Burton et al., 2018). Joseph Jankovic MD, in Bradley and Daroff's Neurology in Clinical Practice, 2022 Median nerve entrapment at the wrist (carpal tunnel syndrome)ĬTS is by far the most common entrapment neuropathy seen in clinical practice.