Parinaud's syndrome in posterior stroke treated with intravenous thrombolysis: A case report

Parinaud's syndrome, or dorsal midbrain syndrome, is characterized by vertical gaze palsy, light-near dissociation, convergence-retraction nystagmus, and bilateral eyelid retraction. The majority of cases are caused by pineal region tumors, whereas vascular etiologies are less frequent. Early recognition of this neuro-ophthalmological syndrome can be crucial for diagnosing brainstem strokes, particularly when initial neuroimaging findings are normal.

A 66-year-old man presented to the Emergency Department with sudden-onset vertical diplopia, dysarthria, and gait instability, consistent with an acute neurological event. Neuro-ophthalmological examination revealed the complete classical triad of Parinaud's syndrome. Brain magnetic resonance imaging (MRI) and computed tomography angiography (CTA) showed no acute ischemic lesions or vascular abnormalities. Given the disabling oculomotor findings and the strong suspicion of posterior circulation ischemia, intravenous thrombolysis with recombinant tissue plasminogen activator (rtPA) was administered within 3.5 h of symptom onset. The patient achieved complete neurological and oculomotor recovery within 24 h, and follow-up brain MRI confirmed the absence of structural damage.

The present case illustrates Parinaud's syndrome, a rare neuro-ophthalmological manifestation of acute posterior circulation ischemia, treated with intravenous thrombolysis. Although its global prevalence remains unknown, published series show that the syndrome is exceptionally uncommon, with vascular etiologies representing approximately 25% of cases-making stroke the second most common cause after pineal region tumors.In contrast to pineal region tumors, which typically produce a slowly progressive clinical course, vascular etiologies are characterized by abrupt symptom onset.

This case underscores the importance of recognizing Parinaud's syndrome as a possible manifestation of posterior circulation ischemia, particularly when early neuroimaging findings appear normal. Its rarity and atypical presentation can make therapeutic decision-making challenging in the acute setting, highlighting the diagnostic value of a meticulous ocular examination.