A successful 48-year old attorney was told he was hypertensive, but did not take his blood pressure medications. He was apparently well until 4 days after his birthday, when he developed several episodes of blurred vision, "like a shade coming down," involving his left eye. These attacks each lasted less than an hour. He was referred for neurologic evaluation but because of a busy schedule, canceled the appointment. Several weeks later, he complained to his wife of a left-sided headache. She found him 1/2 hour later, slumped in a chair apparently confused and paralyzed on the right side.
Neurologic examination in the hospital revealed total paralysis of the right arm and severe weakness of the right face. The leg was only mildly affected. Deep tendon reflexes were initially depressed on the right side, but within several days, became hyperactive; there was Babinsky response on the right. The patient was globally aphasic; he was unable to produce any intelligible speech and appeared to understand only very simple phrases. A CT scan revealed an infarct in the territory of the middle cerebral artery of the left side. Angiography revealed occlusion of the internal carotid artery. The patient recovered only minimally.
What was the cause of the several episodes of blurred vision
The CT scan showed that the infarct included the territory of the middle cerebral artery but the occlusion involved the internal carotid artery. Why was the territory of the anterior cerebral artery not infarcted?
I chose an easy case this time , just to make sure that everyone knows the basics