Isolated oculomotor palsy due to acute ischemic midbrain stroke

Excerpt

A 44-year-old woman presented with acute diplopia in the emergency department. On initial neurological exam, she had an isolated, left-sided oculomotor palsy with ptosis and mydriasis (Fig. 1). Urgent brain CT and CT angiography were normal. A successive brain MRI showed a subacute ischemic stroke in the left paramedian midbrain (Fig. 2a–c). Thrombolysis was not performed because of the elapsed time interval of 4.5 h since diplopia onset. Over the following 18 h, the patient developed a right-sided, mild ataxic hemiparesis and dysarthria. Repeat brain MRI demonstrated an expansion of the ischemia in the left midbrain now reaching further laterally and rostrally into the crus cerebri and tegmentum (Fig. 2d, e).

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