68歲男性，左眼瞼下垂，無其它症狀。左眼使用冰敷，可以改善症狀。
臨床診斷是？
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重症肌無力
Myasthenia gravis
Image Challenge! A 68-year-old man presented with unilateral ptosis with no other symptoms. Application of an ice pack to the left eye improved his symptoms. What’s the diagnosis? http://nej.md/206y4a1
