|
Year |
2002 |
|---|---|
|
Question Number |
227. |
|
Category |
Hand |
Question
A 42-year-old factory worker who has worked as a finish grinder on metal castings for the past 11 years reports persistent numbness of his fingers. Examination and diagnostic work-up will most likely reveal which of the following findings?
1- Cold intolerance
2- Diminished ulnar artery flow noted on Allen’s test
3- Abnormal motor and sensory latencies
4- Increased vibration and temperature thresholds
5- Hyperhidrosis (increased palmar sweating)
Figures
Answer (click for answer)
Preferred Response: 4
They are describing symptoms of carpal tunnel syndrome. Other symptoms include night pain, tingling in median nerve distribution, weakness, and clumsiness – though he is only complaining of numbness. The first electrodiagnostic abnormality seen in carpal tunnel syndrome is an increase in the distal palmar median sensory latency. Sensory axons are larger than motor axons and exhibit a greater constriction of the axon at each node, therefore alterations in the node secondary to pressure changes are noted here first. Vibration and temperature, the quickly adapting fibers are affected initially. Motor latencies would be seen in advanced disease.
Cold intolerance is typically due to vasospastic (or vaso-occlusive disease) or a glomus tumor. This would likely be the complaint if you noted diminished ulnar artery flow noted on an Allen’s test. Hyperhidrosis may be due to increased sympathetic nerve tone.
Reference: Stromberg T, Dahlin LB, Lundborg G: Hand problems in 100 vibration-exposed symptomatic male workers. J Hand Surg Br 1996;21:315-319.
Rosen I, Stromberg T, Lundborg G: Neurophysiological investigation of hands damaged by vibration: Comparison with idiopathic carpal tunnel syndrome. Scand J Plast Reconstr Surg Hand Surg 1993;27:209-216.