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What is Parinauds syndrome?
Parinauds syndrome is also known as the dorsal midbrain or collicular syndrome.
The lesion is in the rostral dorsal midbrain, damaging the superior colliculi and pretectal structures.
Parinaud syndrome is caused by masses of the pineal region compressing the midbrain tectum.
It is characterized by difficulty with ocular convergence, upgaze palsy, light-near dissociation, eyelid retraction, and convergence nystagmus.
Patients report difficulty in looking up and blurring of distant vision. The common tetrad of findings is:
• Paralysis of upgaze and accommodation, but sparing of other eye movements
• Normal to large pupils with light-near dissociation (loss of pupillary reflex to light with preservation of pupilloconstriction in response to convergence)
• Eyelid retraction
• Convergence-retraction nystagmus (eyes make convergent and retracting oscillations following an upward saccade)
Causes include tumors of the pineal gland, stroke, hemorrhage, trauma, hydrocephalus, or multiple sclerosis.
The upgaze palsy can be mimicked by progressive supranuclear palsy, thyroid ophthalmopathy, myasthenia gravis, Guillain–Barré syndrome, or congenital upgaze limitation.
Sources
Caplan LR: “Top of the basilar” syndrome. Neurology 30:72-79, 1980. Bauby J-D: The diving bell and the butterfly . New York: Alfred A. Knopf, 1997.
