Dorsal Midbrain Syndrome (Parinaud's)

Parinaud's Syndrome, also known as dorsal midbrain syndrome is a group of abnormalities of eye movement and pupil dysfunction. It is caused by lesions of the upperbrain stem and is named for Henri Parinaud^[1][2] (1844–1905), considered to be the father of French ophthalmology.

Parinaud's Syndrome is a cluster of abnormalities of eye movement and pupil dysfunction, characterized by:

1. Paralysis of upgaze: Downward gaze is usually preserved. This vertical palsy issupranuclear, so doll's head maneuver should elevate the eyes, but eventually all upward gaze mechanisms fail.^[3]
2. Pseudo-Argyll Robertson pupils: Accommodative paresis ensues, and pupils become mid-dilated and show light-near dissociation.
3. Convergence-Retraction nystagmus: Attempts at upward gaze often produce this phenomenon. On fast up-gaze, the eyes pull in and the globes retract. The easiest way to bring out this reaction is to ask the patient to follow down-going stripes on an optokinetic drum.
4. Eyelid retraction (Collier's sign)
5. Conjugate down gaze in the primary position: "setting-sun sign". Neurosurgeons will often see this sign most commonly in patients with failed ventriculoperitoneal shunts.(Fonts: Wikipedia)