Charcot-Marie-Tooth disease: CMT2, CMT4, and others
Sep. 10, 2023
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This article includes discussion of carpal tunnel syndrome and median nerve entrapment at the wrist. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.
Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy with a prevalence of about 270 per 100,000. The etiology is compression of the median nerve in the carpal tunnel. Clinical manifestations consist of intermittent pain, numbness, and tingling in the fingers that is dependent on the position of the hand and wrist and commonly associated with subjective weakness of grip. Diagnosis is made on the basis of clinical complaints and electrodiagnostic studies. Treatment is conservative or surgical depending on the severity of the symptoms. Data on carpal tunnel syndrome in pregnancy reveal that about half of the patients remain symptomatic at 6 months after delivery. Ultrasound has emerged as a useful and less invasive technique for evaluation of carpal tunnel syndrome. Endoscopic carpal tunnel release supposedly produces less scarring than open release, but is more expensive and precludes visualization of the median nerve proper. Controversy continues about which surgical procedure is the best. Some studies showed increased prevalence of carpal tunnel syndrome in patients with cardiac amyloidosis. In this article, the author discusses updates on diagnosis and management.
• Carpal tunnel syndrome is the most common entrapment neuropathy.
• Peripheral nerve ultrasound imaging is proposed as a painless rapid screening test for carpal tunnel syndrome.
• Electrodiagnostic studies have a sensitivity of up to 95% for the diagnosis when detailed studies are performed.
• In most patients, including elderly patients and patients with diabetes, surgical carpal tunnel release should be considered if conservative measures fail.
The first description of a chronic median nerve entrapment at the wrist was by Paget (42) concerning a patient with a previous distal radius fracture (49). This was a severe entrapment accompanied by ulceration in the first 3 fingers. Paget noted recovery of the ulcerations with rest and an increase of symptoms with use of the hand secondary to nerve compression. Putnam first described the classical clinical symptoms of intermittent nocturnal hand paresthesias with subjective hand swelling and an improvement with shaking of the hand (46). A careful autopsy study by Marie and Foix documents the thinning of the median nerve under the flexor retinaculum in a patient with bilateral isolated thenar atrophy (33). They made the suggestion that transection of this ligament may have been therapeutic. The first surgery for carpal tunnel syndrome was done in 1933 at the Mayo Clinic. Carpal tunnel syndrome received increasing attention in the 1940s and 1950s from both neurologists and surgeons. The development of clinical electrodiagnostic testing with EMG and nerve conduction studies in the 1960s added a valuable diagnostic tool. The use of high resolution ultrasound imaging to study the median nerve in carpal tunnel syndrome was first published in 1992 (06); however, most studies have appeared since early 2000.
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