Prominent eyelid nystagmus with upbeat nystagmus

Lid nystagmus is commonly seen with vertical nystagmus, especially in upbeat nystagmus (UBN) since there is simultaneous excitation of the superior rectus and levator palpebrae (LP) muscles via the central caudal nucleus (part of the 3rd nucleus). This is necessary so that the lid stays out of the visual axis in upgaze. When the eyes move downward, the LP descends with the globe (to protect the cornea) mainly by relaxing. This patient presented with dizziness and imbalance and had very subtle spontaneous UBN (which was not initially appreciated), but with much more prominent lid nystagmus which can be seen with each upward quick phase of the nystagmus. Given this central pattern of vestibular nystagmus, MRI was performed which showed cerebellar and diffuse brainstem (medulla to midbrain although only one representative pontine image is included here) "salt and pepper" contrast enhancement, suggestive of CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids). She improved after administration of steroids.