Abstract
We herein report the case of a pediatric patient with an equilibrium disturbance and upbeat nystagmus. She was taken to a pediatric clinic for a fever that had lasted for five days and because she was unable to stand. She was diagnosed to have acute cerebellitis by a head MRI scan. Cerebellitis commonly manifests with downbeat nystagmus, because the pathway from the flocculus to the anterior semicircular canal and to the superior rectus muscle is disinhibited, increasing the tone of the superior rectus muscle, resulting in upward eye rolling. In response,the brainstem tries to correct this imbalance of the extraocular muscle tone by pulling the eyeball downward. In this case, we thought that the cerebellitis did not disinhibit the pathway, but rather over-inhibited it by exciting the Purkinje cells due to the extensive inflammation, thus resulting in the eye rolling downward, and upbeat nystagmus thereafter occurred.
