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Year |
2001 |
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Question Number |
273) |
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Category |
Select |
Question
An 18 y/o man with recurrent bilateral ankle instability reports that his symptoms have been slowly progressing . He denies problems with coordination, but he notes easy fatigability when he types. History reveals that his grandmother had disfigured feet. Examination reveals bilateral cavo varus feet and peroneal weakness. He has intrinsic muscular weakness in his hands. To confirm the diagnosis which of the following studies should be obtained?
1) radiographs of the spine
2) electrocardiography
3) electromyography
4) MRI of the feet
5) CBC
Figures
Answer (click for answer)
Preferred answer # 3
The patient described has Charcot-Marie- Tooth disease. This is a hereditary neurological disorder characterized by a motor-sensory demyelinating neuropathy. There are two forms of the disease. The first CMT-1 the hypertrophic form has an onset in the second decade of life and CMT-2 the neuronal form has an onset during the third to fourth decade of life. CMT-2 has more involvement of the feet. The orthopaedic manifestations of CMT include pes cavus, hammertoes, peroneal weakness, as well as intrinsic hand muscle weakness and wasting. This is a peripheral nervous system disease so an EMG is the test of choice to establish the diagnosis. Low conduction velocity with prolonged distal latency is noted in the peroneal, ulnar, and median distributions. Only the MRI of the feet would be applicable to this patient but it would not provide any information regarding the etiology of the condition.
Reference: Beay, J.H.: Orthopaedic Knowledge Update 6. Rosemont, IL, Amercian Academy of Orthopaedic Surgeons, 1999, pp235-245.
Mizel, M.S., Miller, R.A., Scioli, M.W.: OKU: Foot and Ankle 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp79-100.
Miller, Mark, D. Review of Orthopaedics third edition, Philadelphia, PA, W.B. Saunders Company, 2000, p 163.