Carpal tunnel syndrome and hyperthyroidism. A prospective study.

We carried out a prospective study to determine the frequency and evolution of carpal tunnel syndrome (CTS) in patients with hyperthyroidism. An initial survey revealed CTS in 5% of these patients when hyperthyroidism was diagnosed. During the clinical and neurophysiologic follow-up for a two-year period, four more patients developed CTS; of these, two had uncontrolled hyperthyroidism, and the other two had iatrogenic hypothyroidism. The clinical and neurophysiologic evolution suggests a relationship between both diseases. The symptoms of CTS remitted if endocrinopathy is controlled. Surgery is, in general, not necessary. CTS can be considered another peripheral neurological manifestation associated with hyperthyroidism.