A 68-year-old man comes to the physician because of double vision and unilateral right eye pain that began this morning. He has hypertension, and type 2 diabetes mellitus. The patient has smoked two packs of cigarettes daily for 40 years. His current medications include lisinopril, metformin, and insulin with meals. Physical examination shows right-sided ptosis and abducted. He can only minimally adduct the right eye. An MRI of the head shows no abnormalities. His fingerstick blood glucose concentration is 325 mg/dL. This patient's condition is most likely due to which of the following etiologies?

Question

Quizplus · Accepted Answer

Eductional Objective: Diabetic mononeuropathy often involves cranial nerve III.  It is caused by predominantly central ischemia, which affects the somatic nerve fibers but spares peripheral parasympathetic fibers.  Symptoms include ptosis, a "down and out" gaze, and normal light and accommodation reflexes.

A 68-Year-Old Man Comes to the Physician Because of Double