Acute cerebellitis is an uncommon clinical entity . It is usually manifested in children. It produces imaging features of cerebllar hemispheric or vermian or both oedema with apparently normal supratentorial compartment. Obstructive hydrocephalus due to aqueductal nannrowing due to oedema is possible The usual agents are viral and amongst them herpes as well as epstein barr virus predominate. In our country it should not be mistaken for Tuberculosis as findings could mimic with leptomeningeal and tentorial enhancement. On admnistration of acyclovir pt may deteriorate if steroid is withheld. Post contrast imaging shows intravascular enhancement (i.e. seeing vessels better in the ROI) which is typical for acute stroke and vasculitis. The etiology of the MRI signal changes and enhancement in cerebellitis remains speculative. The cerebellar swelling and parenchymal signal changes most likely reflect encephalitis with edema and inflammation. The hyperintensities on T2-WI involved the cerebellum diffusely and symmetrically, including the vermis and cerebellar hemispheres; the grey matter appeared more abnormal than the white matter.
Case by Dr MGK Murthy
Sr Consutlant Radiologist