Brainstem infarct from cervical vertebral artery dissection presenting as a transient Parinaud syndrome.

Purpose: To report a case of transient diplopia and upgaze paresis in the setting of acute dorsal midbrain infarcts from a cervical vertebral artery dissection in an otherwise healthy man. Observations: A 33-year old man presented to the ophthalmology urgent clinic with a 1 h history of blurred and double vision, asthenopia, and a mild focal left posterior headache. Ocular motility examination revealed a profound upgaze palsy and convergence-retraction horizontal jerk nystagmus in attempted upgaze that gradually improved over the course of 1 h. Emergent neuroimaging revealed focal dorsal midbrain and left cerebellar microinfarcts along with a high-cervical left vertebral artery dissection. He was discharged on a 3-month course of therapeutic anticoagulation with close vascular neurology follow-up. Conclusions and Importance: Prompt recognition of clinical signs suggestive of dorsal midbrain syndrome can facilitate timely diagnosis and workup, especially in the presented case where findings were very short-lived. The acute microinfarcts to the dorsal midbrain as evidenced on neuroimaging are compatible with the transient nature of the patient's symptoms, and the recognition of vertebral dissection as the source critically important to his management.