A 35-year-old right-handed construction worker presents with complaints of nocturnal numbness and pain involving the right hand. Symptoms wake him and are then relieved by shaking his hand. There is some atrophy of the thenar eminence. Tinel sign is positive. Which of the following is the most likely diagnosis?A. Carpal tunnel syndrome
Carpal tunnel syndrome results from median nerve entrapment and is frequently associated with excessive use of the wrist. The process has also been associated with thickening of connective tissue, as in acromegaly, or with deposition of amyloid. It also occurs in hypothyroidism, rheumatoid arthritis, and diabetes mellitus. As in this patient, numbness is frequently worse at night and is relieved by shaking the hand. Atrophy of the abductor pollicis brevis as evidenced by thenar wasting is a sign of advanced disease and an indication for surgery. Tinel sign (paresthesia induced in the median nerve distribution by tapping on the volar aspect of the wrist) is characteristic but not specific. De Quervain tenosynovitis causes focal wrist pain on the radial aspect of the hand and results from inflammation of the tendon sheath of the abductor pollicis longus. It should not produce a positive Tinel sign or evidence of median nerve dysfunction. Amyotrophic lateral sclerosis may present with distal muscle weakness but does not cause pain. Diffuse atrophy and muscle fasciculation would be prominent. Rheumatoid arthritis would not produce these symptoms unless inflammation of the wrist was causing median nerve entrapment in the carpal tunnel. Guillain-Barré syndrome is a rapidly progressive polyneuropathy that typically presents with an ascending paralysis.