A 60-year-old man with diabetes acutely develops double vision and discomfort in his left eye. On examination, there is ptosis of the left eyelid, the eye is rotated down and out, and the pupil is 3 mm and reactive to light. The right eye is normal. Which of the following is the most likely diagnosis?
Third nerve palsy can result in ptosis of the eyelid. There is also loss of the ability to open the eye, and the eyeball is deviated outward and slightly downward. With complete lesions, the pupil is dilated, does not react to light, and loses the power of accommodation. In diabetes, the pupil is often spared. The sixth cranial nerve can also be affected by diabetes, but this is much less common.
fourth nerve palsy
diabetic autonomic neuropathy
third nerve palsy
sixth nerve palsy
C.N.S.